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SA - Buderus 500-24S/24C/28C

1. Disconnect the 230V AC plug item 1 from the fan Set multimeter to measure resistance Check the power supply cable of the fan for breaks The electrical resistance measured at each individual wire must be approximately 0 Q Check the power supply cable of the fan for internal short circuits The level of electrical resistance measured between two wires chosen at random must be infinitely high See also box 287 Insert the fan connection plug Refit the DBA control panel following the above procedure in reverse order Refit the casing and place the boiler into operation see box 51 53 54 or 55 Buderus Ltd http www buderus domestic co uk 42 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 DANGER OF FATAL ACCIDENT A due to electric shock CAUTION L To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection Take the boiler out of service and tip the DBA control panel forwards see box 43 44 47 or 63 Loosen the six screws and remove the rear section see box 70 Pull out the tacho cable plug item 1 Set multimeter to measure resistance Attach the multimeter Check the tacho ca
2. you can read the current cI bu As soon as the DHW temperature in C appears on the display h DHW temperature or adjust it as required See also box 18 Adjust DHW temperature Yes No Lower lower the DHW temperature with the V button Higher increase the DHW temperature with the A button Press the button once Prt To in Configured heating mode As soon as F rx is displayed you can verify the current heating mode of adjust it as required See also box 18 Adjust configured heating mode Yes No Use single or multiple operation of the O and A buttons to activate and disable heating mode g Pr TI Heating mode on Pr f Heating mode off 7x Press the button once HH Configure CH flow temperature in C See also box 18 As soon as HH is displayed you can verify the current CH flow temperature or adjust it as required Adjust CH flow temperature Yes No Lower lower the CH flow temperature with the button Higher increase the CH flow temperature with the A button Has at least 10 seconds passed without a button being pressed and or was mains supply interrupted Yes No Press the button once Any adjustments that you have made will now be confirmed Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 step 11
3. A AI DY aap rail TY gt yy MDA Cai rc cl ia ll Cc ce ci lt i Pull the heat exchanger towards the arrow to remove Clean the heat exchanger with compressed air a high pressure hose or with water and a soft brush S _ MA A CAUTION N a K A L When cleaning the heat exchanger never use a steel R le brush gt CAUTION LA AA LS When using compressed air Use eye protection inhalation protection and hearing protection Cine CT S SS Qc a Di U hin Cconmy l 5 f CAUTION Check the seal on the heat exchanger casing item 1 for A Observe the position of the heat exchanger during signs of ageing and replace if required fitting Insert the upper section of the heat exchanger at Replace the four O rings item 2 two on each side the top Fit the new or cleaned heat exchanger and all other components by following the above procedure in reverse CAUTION A The released coil item 1 touches the underside CAUTION Insert a new heat exchanger gas air seal before fitting the gas air unit We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02
4. 1 This error code may deactivate again automatically after a specific time without reset Heating and hot water are now available once more 2 In the event of this malfunction the pump is started up and remains in continuous operation in order to minimise the possibility of the heating system freezing up We reserve the right to make technical modifications Buderus Ltd http Avww buderus domestic co uk PE 20 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 step 1 step 2 step 3 step 4 step 5 step 6 step 7 step 8 step 9 step 10 step 11 step 12 step 13 step 14 step 15 step 16 step 17 step 18 step 19 step 20 step 21 step 22 step 23 step 24 step 25 step 26 step 27 step 28 step 29 We reserve the right to make technical modifications No indication on DBA control panel display Check to ensure that the power supply cable to the mains switch box has been installed correctly Is the power supply cable to the mains switch box correctly installed Yes No Install the power supply cable correctly see box 54 Check to ensure that the operating switch on the boiler DBA control panel is set to position 1 as per box 55 Is the operating switch on the boiler DBA control panel set to I ON Yes No Turn the operating switch on the DBA control panel of the boiler to position 1 ON see box 55 Check to the
5. 2P JA fat E ANTIS N ATINS ay ANTIS AH ANTIS UE ANIS ANIS pup ANTIS eH ANTIS oF ANTIS H ANTIS g ANTIS raj 1 This error code may deactivate again automatically after a specific time without reset Heating and hot water are now available once more INTINS Display indication Key to display code Fault The flow sensor has detected a temperature increase in the heating system water of over 5 C sec Fault The tacho signal from the fan has failed during the operating phase Fault The tacho signal from the fan is not present during the pre operative or operating phase Fault No current of air after a certain time Fault The fan runs too slowly or too fast Fault The flow sensor and safety sensor have detected a CH flow temperature of over 105 C Fault The sensor test has failed Fault The contacts of the flow sensor and safety sensor are shorted to each other or there is a short circuit to earth ground or the flow or safety sensor has detected a CH flow temperature of above 130 C Fault The contacts of the flow sensor or safety sensor are broken Fault During the ignition phase the system has detected an insufficient ionisation current Fault After four startup attempts the system h
6. Check the mains cable of the glow ignitor for breaks The electrical resistance measured at each individual wire must be approximately 0 Q Check the mains cable of the glow ignitor for internal short circuits The level of electrical resistance measured between any two wires must be infinitely high Connect the plug of the glow ignitor Fit the DBA control panel and place the boiler into operation see box 51 54 or 55 DANGER OF FATAL ACCIDENT 4 f due to electric shock Take the boiler out of operation see box 43 44 or 47 Remove the plug of the glow ignitor see box 131 Wn TE DA D D Seth a It 677 Sf Loosen the fixing nut of the glow ignitor item A Remove the mounting plate item 2 Detach the glow ignitor item 3 We reserve the right to make technical modifications CAUTION The filament of the glow ignitor consists of sintered material and is highly breakable Fit a new glow ignitor Connect the plug of the glow ignitor Put the boiler into operation see box 51 54 or 55 Take the boiler out of operation see box 43 44 or 47 Use a multimeter that is specially designed to measure the ionisation current Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 53 Set the multimeter to m
7. Subsection box heck the actuation of the servomotor of the internal three way valve see box 186 step 29 Does the servomotor of the internal three way valve start up correctly step 30 step 31 step30 Replace the servomotor of the internal three way valve see box 191 gt box 43 step31 Check the power supply cable of the internal three way valve see box 192 step32 Is the power supply cable of the internal three way valve in good condition Yes gt box 42 No gt step 33 step 33 Replace the cable loom or the affected part thereof box 43 step 34 Check the movement of the servomotor of the Buderus 24V AC external three way valve see box 212 step 35 Does the servomotor of the Buderus 24V AC external three way valve operate correctly Yes step 36 No gt step 39 step 36 Check to ensure that the the Buderus 24V AC external three way valve has been fitted correctly see box 228 step 37 Has the Buderus 24V AC external three way valve been fitted correctly Yes gt step 45 No gt step 38 step 38 Install the Buderus 24V AC extemal three way valve correctly see box 228 gt box 43 step 39 Check to ensure that the Buderus 24V AC external three way valve is actuated correctly see box 213 and box 229 step 40 Does the Buderus 24V AC external three way valve actuate correctly Yes step 41 No gt step 42 step41 Replace the servomotor of the Buderus 24V AC external three
8. operating code OL or Somewhat later 20 24V DC must be detectable at both the centre and upper contacts item 1 and 2 Put the boiler into operation see box 51 54 or 55 Take the boiler out of operation and remove the DBA control panel see box 43 44 47 63 or 70 We reserve the right to make technical modifications COCOCODOOOSCOOO eO On Set multimeter to measure resistance Check the power supply cable of the gas valve for breaks The electrical resistance measured at each individual wire must be approximately 0 Q Check the power supply cable of the gas valve for internal short circuits The level of electrical resistance measured between two wires must be infinitely high Insert the gas valve plug Fit the DBA control panel and place the boiler into operation see box 51 54 or 55 Take the boiler out of operation see box 43 44 or 47 Remove the power supply plug of the gas valve see box 168 Buderus Ltd http www buderus domestic co uk 56 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 180 250 Q Set multimeter to measure resistance Take a reading at the coils to check the internal electrical resistance of the two gas valve coils The electrical resistance between the middle
9. step 19 step 18 box 42 step 21 step 20 box 42 step 22 box 41 step 23 step 34 step 25 step 28 box 42 step 27 box 42 step 30 step 31 Buderus Ltd http www buderus domestic co uk 25 step 30 step 31 step 32 step 33 step 34 step 35 step 36 step 37 step 38 step 39 step 40 step 41 step 42 step 43 step 44 step 45 step 46 step 47 step 48 Replace the servomotor of the internal 3 way valve see box 190 Check the power supply cable of the internal 3 way valve see box 191 Is the power supply cable of the internal 3 way valve in good condition Yes No Replace the cable loom or the affected part thereof Check the movement of the servomotor of the Buderus 24V AC external 3 way valve see box 211 Does the servomotor of the Buderus 24V AC external 3 way valve operate correctly Yes No Check to ensure that the the Buderus 24V AC external 3 way valve has been fitted correctly see box 227 Has the Buderus 24V AC external 3 way valve been fitted correctly Yes No Install the Buderus 24V AC external 3 way valve correctly see box 227 Check to ensure that the Buderus 24V AC external 3 way valve is actuated correctly see box 212 and box 228 Does the Buderus 24V AC external 3 way valve actuate correctly Yes No Replace the servomotor of the Buderus 24V AC external 3 way valve see box 217 Check
10. Set multimeter to measure resistance Take a reading at the ionisation electrode to check whether there is a possible break in the electrode cable The electrical resistance of the ionisation electrode cable must be approximately 0 Q We reserve the right to make technical modifications box 158 3 X Check the ionisation electrode for signs of wear item 2 damage item 3 or soiling item 4 box 159 Replace the ionisation electrode if required Fit the ionisation electrode Connect the plug of the ionisation electrode Put the boiler into operation see box 51 54 or 55 box 160 Check the ionisation circuit earth ground lead ionisation circuit item 1 has been correctly fitted Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 55 Take the boiler out of operation see box 43 44 or 47 Check to ensure that the power supply plug item 1 has been inserted correctly into the gas valve Put the boiler into operation see box 51 54 or 55 Take the boiler out of operation see box 43 44 or 47 Run the boiler at full load see box 54 55 and box 13 step 14 Set the multimeter to measure DC voltage Minimum measuring range 40V DC Check to see if the gas valve has been activated During
11. box 42 step 51 Check the gas air ratio see box 233 step 52 Is the gas air ratio correct Yes step 54 No step 53 step 53 Adjust the gas air ratio see box 233 box 42 step 54 Check the plate heat exchanger or the external hot water cylinder for furring step 55 Is the plate heat exchanger or hot water cylinder furred up Yes step 56 No box 41 step 56 Decalcify the plate heat exchanger and or hot water cylinder see from box 269 box 42 step 57 3 way valve Check the startup of the servomotor of the internal 3 way valve see box 181 and box 185 step 58 Does the servomotor of the internal 3 way valve start up correctly Yes step 59 No step 60 step 59 Replace the servomotor of the internal 3 way valve see box 190 box 42 step 60 Check the wiring of the internal 3 way valve see box 191 step 61 Is the cable correctly connected and free of damage Yes box 41 No step 62 step 62 Replace the cable loom or the affected part thereof box 42 step 63 Check to ensure that the Buderus 24V AC external 3 way valve has actuated correctly see box 212 and box 228 parts 1 and 2 step 64 Does the Buderus 24V AC external 3 way valve actuate correctly Yes step 65 No gt step 66 step 65 Replace the servomotor of the Buderus 24V AC external 3 way valve see box 217 box 42 step 66 Check the wiring of the Buderus 24V AC external 3 way valve see box
12. ing operation and no hot water ing operation and no hot water ing operation and no hot water ing operation and no hot water ing operation and no hot water Diagnosis box 27 box 29 box 29 box 30 box 31 box 32 box 33 box 34 box 35 box 36 box 36 box 37 box 38 box 39 box 41 box 40 box 41 box 40 box 41 2 In the event of this malfunction the pump is started up and remains in continuous operation in order to minimise the possibility of the heating system freezing up We reserve the right to make technical modifications Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Buderus Ltd http www buderus domestic co uk 19 Display indication Reset required Other symptoms Diagnosis Key to display code Fault Yes No heating operation and no hot water box 41 The DBA control panel is defective 2 Fault Yes box 41 Short circuit in the gas valve Fault No No heating operation and no hot water box 41 The contacts of the KIM EEPROM on the DBA control 1 panel circuit board may be loose or short circuited Fault No heating operation and no hot water The DBA control panel is defective Fault Applies only to a system blocking error flashing Reset is carried out display code This code appears after the reset button is pressed for 5 seconds
13. box 59 Initial startup Open the gas tap item 2 Put the boiler into operation see box 53 54 or 55 Buderus Ltd http Awww buderus domestic co uk 40 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Press the menu button item 1 on the DBA control panel of the boiler Gen 1 Configure the menu as required see box 14 DANGER OF FATAL ACCIDENT A due to electric shock Take the boiler out of operation see box 43 44 or 47 Remove the casing from the boiler see box 47 Loosen the cap screw on the DBA control panel item 1 Tip the DBA control panel forwards item 2 We reserve the right to make technical modifications Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 ooooooo p o 000000000000000 00000 000000 o e o Remove the rear section of the DBA control panel see box 70 Remove the fuse from the fuse holder Check the fuse with a multimeter If the fuse possesses infinitely high electrical resistance it is defective Replace the defective fuse with a new 2 5 AT slow blow reserve fuse Refit the DBA control panel following the above procedure in reverse order Refit the casing and place the boiler into operation see box 51 53 54 or 55
14. step 12 step 15 step 16 step 19 step 20 step 22 step 21 step 1 Buderus Ltd http www buderus domestic co uk 13 Start phase step 1 Turn the mains switch to ON step 2 Turn the operating switch on the DBA control panel of the boiler to position 1 ON see also box 11 step 3 Is a 3 way valve fitted Yes step 4 No step 6 step 4 Is the 3 way valve set to hot water mode Yes step5 No step 6 step 5 The Buderus 24V AC external 3 way valve is turned to heating mode in 7 5 seconds while an internal 3 way valve is turned to heating mode in 2 seconds step6 KOD The display on the DBA control panel of the boiler is checked maximum of one second step 7 24 Current CH flow temperature in C See also box 20 step 8 OL The boiler begins to warm up Start of pre purge phase The fan runs for 15 seconds at about 60 of maximum speed Checking phase step 9 Has the pre purge been completed correctly Yes step 11 No step 10 step10 Deal with fault The error code which is now displayed can be found in box 20 Deal with the fault Operating phase step11 OH Operating code See also box 20 The boiler is ready for operation No current heat requirement step12 Start of pump over run time via the heating system The pump over run time via the heating system factory adj
15. DANGER OF FATAL ACCIDENT Z S due to electric shock CAUTION Z N To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection Remove the casing and place the boiler out of operation see box 47 43 or 44 Buderus Ltd http www buderus domestic co uk 41 z DD R e oO o FN 0 S 9 o KO JE N Set the multimeter to VAC Minimum value 250 V AC Disconnect the 230V AC plug item 1 from the fan Attach the multimeter to the two outer contacts blue and brown of the fan connection plug Start system at full load see box 54 55 or 13 Check whether with operating code OL active there is a voltage of 230 V AC at the two outer contacts blue and brown of the plug Take the electrical system of the boiler out of operation see box 43 and 44 Insert the fan connection plug Refit the casing and place the boiler into operation see box 51 53 54 or 55 A DANGER OF FATAL ACCIDENT L amp L due to electric shock CAUTION L amp S To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection Take the boiler out of service and tip the DBA control panel forwards see box 43 44 47 or 63 We reserve the right to make technical modifications
16. 110 230 V AC is measured at the plug box 133 Take the boiler out of operation see box 43 Connect the plug of the glow ignitor Put the boiler into operation see box 54 55 or 51 We reserve the right to make technical modifications box 134 Check the glow ignitor resistance DANGER OF FATAL ACCIDENT due to electric shock Take the boiler out of operation see box 43 44 or 47 Remove the plug of the glow ignitor see box 131 box 135 A Set multimeter to measure resistance Check to see if the electrical resistance of the glow ignitor lies between 50 and 300 Q Connect the plug of the glow ignitor Fit the casing and place the boiler into operation see box 51 54 or 55 box 137 Check the glow ignitor power supply cable DANGER OF FATAL ACCIDENT due to electric shock CAUTION To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection Take the boiler out of serve and tip the DBA control panel forwards see box 43 44 47 or 63 Loosen the six screws and remove the rear section see box 70 Remove the plug of the glow ignitor see box 131 Buderus Ltd http Awww buderus domestic co uk 52 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Set multimeter to measure resistance
17. 250V AC Put the boiler into operation see box 54 and 55 Carry out a multimeter check to verify whether 230V AC is present at both outer contacts L and N of the power supply plug of the pump during locking fault code ol We reserve the right to make technical modifications Insert the power supply plug of the pump Fit casing see box 51 A DANGER OF FATAL ACCIDENT ZLN due to electric shock Take the boiler out of serve and tip the DBA control panel forwards see box 43 44 47 or 63 Loosen the six screws and remove the rear section see box 70 Remove the power supply plug of the pump see box 92 Check the power supply cable of the pump for breaks The electrical resistance measured at each individual wire must be approximately 0 Q Check the power supply cable of the pump for internal short circuits The level of electrical resistance measured between two wires chosen at random must be infinitely high Fit the power supply plug of the pump fit the DBA control panel and place the boiler into operation see box 53 54 or 55 Take the boiler out of operation and drain the heating system see box 43 44 47 45 49 or 50 Buderus Ltd http www buderus domestic co uk 46 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Loosen the four Allen screws on the pump Remove the top section of the
18. No Yes No step 62 step 23 step 18 step 25 step 28 step 26 step 46 step 27 step 62 step 24 step 32 step 72 step 39 step 34 step 35 step 32 step 29 step 38 step 46 step 19 Buderus Ltd http www buderus domestic co uk 15 step49 Does the ionisation current exceed 1 4 pA microamperes within 5 seconds Yes step 50 No step 72 step50 H The boiler is in heating mode The symbol 6 lights up The startup load on the boiler is 49 for the first 13 seconds for the purposes of flow monitoring It is then increased or decreased step51 Is there a heating requirement from the room temperature controller Yes step 52 No gt step 57 step52 Is the heat system flow temperature 6 C higher than the target setting Yes step 53 The target setting is entered at the DBA control panel if room temperature adjustment is required No gt step 50 step53 O4 The gas valve is closed and the burner is shut down step54 The symbol 6 goes out step55 The fan stops step56 Is the CH flow temperature 6 C lower than the target setting Yes step 47 No gt step 53 step57 The symbol lt 10 goes out step58 OH The gas valve is closed and the burner is shut down step59 The symbol 6 goes out step60 Start of pump over run time via the heat
19. Other manuals available for this boiler are user manual installation and maintenance instructions wall spacing frame instructions We reserve the right to make technical modifications These service instructions apply to Buderus wall mounted condensing gas boilers 500 24 S 500 24 C and 500 28 C Model C13 x gt 33 x C530 C736 Type GB IE Ilo43p 20 mbar 37 mbar Power rating 230 VAC 50 Hz IP X4D Fuse rating 1 25 Ampere slow blow The boiler unit consists of the following components 500 Gas condensing boiler 28 Maximum output is 28 kW C Combination boiler with integrated hot water supply S System boiler Important general instructions for use Only use the boiler in accordance with its designated use and the service instructions Installation maintenance and repair must be carried out by competent service engineers e g CORGI registered Only use the boiler in conjunction with the accessories and spare parts indicated in the installation maintenance and service instructions Other accessories and consumables may only be used if they are expressly provided for the designated use and if system performance and safety are not affected in any way The boiler is suitable for connection to fully pumped sealed water systems ONLY Adequate arrangements for completely draining the system by provision of draining valves must be provided in the installation pipework Pipework from t
20. of the country or region of final use CAUTION LS Use this boiler for its intended purpose only DANGER L amp S Notes relating to the heating system water Thoroughly flush the system before it is filled with water Use only untreated water or water treatment product such as Sentinel X100 to fill and top up the sys tem For more information about Sentinel call 0151 420 9563 When using water treatment only products suitable for use with Buderus heat exchangers are permitted e g Sentinel X100 Your warranty is at risk if an incorrect water treatment product is used in conjunction with this appliance For more information contact Buderus Technical Prod uct Support Department It is most important that the correct concentration of the water treatment product is maintained in accordance with the manufacturer s instructions If the boiler is used in an existing system any unsuita ble additives MUST be removed by thorough cleaning BS 7593 1992 details the steps necessary to clean a domestic central heating system In hard water areas treatment to prevent lime scale may be necessary however the use of artificially sof tened water is NOT permitted Under no circumstances should the boiler be fired before the system has been thoroughly flushed Do not use artificially softened water Only plastic pipework containing a polymeric barrier should be used It is allowed to use copper for the first 600 mm GJ 7 NO
21. v arrow and read off the display in Itrs m To increase the DHW flow rate turn the flow regulator in direction To reduce the DHW flow rate turn the flow regulator in direction on Adjust the flow rate of hot water at one of taps where the user is likely to require hot water at an ideal temperature Factory default setting see factory settings in the installation instruction This assumes a cold water input temperature of 10 C Take the boiler out of operation see box 43 44 or 47 We reserve the right to make technical modifications aN _ DANGER OF DAMAGE TO THE SYSTEM A Before removing the servomotor check to see if the 3 way valve is in its heating mode position and wait for the boiler display code OH to appear This prevents sudden pressure surges occurring in the heating circuit while the removal operation is taking place and the resultant accidental opening of the pressure relief valve Remove the stop spring item 1 Remove the servomotor Put the boiler into operation see box 54 and 55 Use the Settings menu on the boiler DBA control panel to adjust the temperature to 60 C see box 14 or 18 Open a hot water tap Check to see if the servomotor of the internal 3 way valve during operating code OL rotates through a full revolution Close the hot water tap Check to see if the servomot
22. way to stop the locking is by pushing the reset O button We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 17 lt 5 eS Q gt Z A gt 4 J gt gt Q gt m gt f J N N gt N gt Display code cI m cI E oF Display indication Reset Key to display code required Standby Standby Standby Operating phase The boiler is in heating mode Operating phase The boiler is in hot water mode The symbol 6 lights up Operating phase Pump over run time via the external cylinder hot water heater The symbol 6 is off Operating phase The switch optimisation program is activated This program is activated if there is more frequently than once every 10 minutes a heating water requirement from an RC or ON OFF control signal This means that the boiler cannot be restarted until at least 10 minutes have elapsed since initial startup of the burner Pre operative phase The boiler prepares for burner startup whenever a heating requirement or hot water requirement arises Ready for operation The boiler is
23. 220 step 67 Is the wiring of the Buderus 24V AC external 3 way valve in correct condition Yes step 71 No step 68 step 68 Replace the wiring of the Buderus 24V AC external 3 way valve box 42 step 69 Check the drive mechanism of the Buderus 24V AC external 3 way valve see box 221 step 70 Is the drive mechanism of the Buderus 24V AC external 3 way valve working correctly Yes step 42 No step 71 step 71 Replace the drive mechanism of the Buderus 24V AC external 3 way valve see box 221 step 72 Check the wiring of the Buderus 24V AC external 3 way valve between the connection box or moving plug and socket connection and the motor of the Buderus 24V AC external 3 way valve see box 287 step 73 Is the wiring in order Yes box 41 No step 74 step 74 Replace the cable loom or the affected part thereof box 42 On combi boilers hot water available but no heating operation On system boilers no heating operation Hot water may be available but no heating operation step 1 Check to ensure that the power supply cable to the mains switch box has been installed correctly see box 54 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 24 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C e Issued 02 2006 step 2 Check to ensure that the preset room temperature or heating configuration of the Buderus control
24. 51 54 or 55 box 256 Replace clean condensate trap and syphon Take the boiler out of operation see box 43 44 or 47 box 257 Check the heat exchanger gas air seal for signs of ageing Replace the heat exchanger gas air seal if required Refit all components following the above procedure in reverse order Open the gas cock and place the boiler into full load operation see box 59 54 55 and 13 Carry out a gas leak check Check the tightness of all components that were loosened in the course of removal i of the burner Use an authorised foam type leak detection product for this purpose Remedy the cause of the gas leak Open the gas cock and place the boiler into operation Remove the condensate trap item 1 and syphon see box 59 54 55 or 51 item 2 box 258 Clean the condensate trap and syphon Take the boiler out of operation see box 43 44 or 47 Fit the new or cleaned syphon Put the boiler into operation see box 51 54 or 55 box 254 box 253 Replace the sight glass Loosen both screws item 1 Remove the sight glass along with the seals We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 69 DANGER OF FATAL ACCIDENT LL due to electric shock DANGER OF FATAL ACCIDENT amp
25. 62 box 42 No or insufficient hot water radiators convectors etc may be heated without current heat requirement step 1 step 2 step 3 step 4 step 5 step 6 step 7 step 8 step 9 step 10 step 11 step 12 step 13 step 14 step 15 step 16 step 17 step 18 step 19 We reserve the right to make technical modifications 22 Set the operating switch on the boiler DBA control panel to position O OFF see box 43 and set the other DBA control panel operating switch to position 1 ON see box 55 Open a hot water tap Check that the hot water pipe directly beneath the external storage type water heater warms up Does the pipe warm up to approx 60 C Yes step5 No step 39 The cause of this fault does not lie with the boiler but with the mains water supply Check to see if the MCW inlet and DHW outlet have been incorrectly connected to the external storage type water heater Are the pipes connected correctly Yes step8 No step 7 Connect the pipeworks correctly box 42 Close the shut off valve in the MCW inlet and open a hot water tap at random to see if water is still flowing Is this the case Yes step 10 No step 11 The cause is a defective thermostat controlled mixer tap a thermostat controlled mixer valve or a short box 42 circuit between the hot and cold water circuits Check to see if any other external part of the drinkin
26. All work on gas supply pipes and gas fitting components must be carried out by a company registered and authorised for this purpose Take the boiler out of operation close the gas cock and drain the heating system see box 46 or 48 to 50 Remove the power supply plug of the glow ignitor see box 131 Remove the plug of the ionisation electrode see box 144 Remove the power supply plug of the gas valve union nut and air silencer tube see box 77 Pull out both fan plugs see box 78 item 1 Remove the gas air unit along with the burner see box 247 and 248 Remove the heat exchanger gas air seal see box 251 Remove the stop spring on the top left hand side of the heat exchanger by turning it towards the arrow Open the four clip fastenings item 1 Clean the heat exchanger with a brush and compressed air or with TAB2 In the event of serious restriction continue with box 261 IN a Remove the stop spring on the bottom right hand side of the heat exchanger by turning it towards the arrow We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 70 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 A Mg o oN
27. Buderus 24V AC external 3 way valve at the boiler Put the boiler into operation see box 54 or 55 Take the boiler out of operation see box 43 or 44 Remove the servomotor of the Buderus 24V AC external 3 way valve see box 218 Check to ensure that the drive mechanism of the Buderus 24V AC external 3 way valve is running smoothly This is done by gradually pushing the spring fully home by hand and allowing the spring to return gradually to its home position Refit the servomotor following the above procedure in reverse order Put the boiler into operation see box 54 or 55 We reserve the right to make technical modifications Take the boiler out of operation and drain the heating system see box 48 to 51 Remove the servomotor of the Buderus 24V AC external 3 way valve see box 213 or 218 Remove the drive mechanism of the Buderus 24V AC external 3 way valve using the wrench supplied with the drive mechanism CAUTION A Note that water will squirt out when the drive mechanism is removed Have a bucket and a supply of dry cloths to hand Fit the new drive mechanism to the Buderus 24V AC external 3 way valve Connect the servomotor of the Buderus 24V AC external 3 way valve by following the above procedure in reverse order Fill the heating system vent it of air and place the boiler into operation see box 52 to 58 Use the letters marked on the 3 way valve to check whet
28. Check the tightness of all components that were loosened during removal of the gas valve Use an authorised foam type leak detection product for this purpose Remedy the cause of the gas leak Put the boiler into operation see box 51 54 or 55 Take the boiler out of service and tip the DBA control panel forwards see box 43 44 47 or 63 Loosen the six screws and remove the rear section see box 70 Room Controller Room Controller Hot water tank sensor Bridge the two contacts terminal 1 and 2 Buderus Ltd http Awww buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 57 Put the boiler into full load operation see box 54 55 or 61 If the boiler goes into heating mode within approx 3 minutes H the cause of the fault lies outside the boiler Take the boiler out of operation see box 43 or 44 Remove the bridge connection Connect the ON OFF or modulating control element to the boiler Put the boiler into operation see box 51 54 or 55 _ CAUTION A As the water pressure and pipework resistance in the plumbing system can vary widely with each situation it is important to adjust correctly the DHW flow rate at the boiler Take a DHW flow rate reading see box 12 Adjust the DHW flow rate at the flow regulator for hot water To check the DHW flow rate press and hold the down
29. Codes of Practise Detailed recommendations are contained in the following British Standard Codes of Practice BS 5440 1 Flues for gas appliances of rated input not exceeding 70 kW BS 5440 2 Ventilation for gas appliances of rated input not exceeding 70 kW BS 5449 Forced circulation hot water systems BS 5546 Installation of gas hot water supplies for domestic purposes 2nd family Gases BS 6798 Installation of gas fired hot water boilers of rated input not exceeding 60 kW BS 6891 Low pressure installation pipes BS 7593 1992 Code of practice for treatment of water in domestic hot water central heating systems IGE UP 1b Tightness testing and purging domestic sized gas installations Health and amp Safety Document No 635 The Electricity at Work Regulations 1989 The manufacturer s notes must not be taken in any way as overriding statutory obligations The design and construction of the Buderus wall mounted condensing gas boiler conforms to the basic specifications listed in the European directive governing gas fired appli ances 90 396 EEC and with respect to EN 625 EN 483 and EN 677 GJ NOTE UJ Observe the corresponding technical rules and the building supervisory and statutory regulations when installing and operating the system A WARNING LL Keep the burner control unit housing CLOSED when working on water bearing components GJ NOTE UJ Itis mandatory to clean and s
30. and lower contact must be approx 70 110 Q item 1 The electrical resistance between the middle and upper contact must be approx 180 250 Q item 2 Fit the power supply plug to the gas valve Put the boiler into operation see box 51 54 or 55 DANGER OF FATAL ACCIDENT A All work on gas pipework and gas fitting components must be carried out by a company registered and authorised for this purpose Take the boiler out of operation and close the gas tap see box 43 44 46 or 47 Remove the fan see box 77 78 79 or 80 1 Pull the gas injector item 1 out of the gas valve We reserve the right to make technical modifications Fit the gas injector to the new gas valve Fit the new gas valve to the fan Fit the fan to the boiler insert the air silencer tube into the fan fit the gas supply pipe to the gas valve and insert the plugs into the fan and gas valve Fit the air silencer tube to the fan CAUTION LS When attaching the gas supply pipe to the gas valve ensure that the flat rubber seal is fitted correctly between the gas supply pipe and gas valve Fit the gas supply pipe to the gas valve Insert the power supply plug into the gas valve then insert the power supply plug and tacho cable plug into the fan Open the gas cock and place the boiler into full load operation see box 59 54 55 or 13 Carry out a gas leak check
31. at A Hy 100 max heating capacity Wait for 1 minute until the boiler starts at full load Measure the working gas pressure at the appliance Measure the difference between the static and working gas input pressure The working pressure may be for natural gas minimum 17 mbar and for propane minimum 30 mbar Take the boiler out of operation and close the gas tap see box 43 44 or 46 Remove the pressure gauge Tighten the screw on the gas connection pressure measurement nipple Open the gas tap see box 59 Use a detection product to check the gas connection pressure measurement nipple for leaks Use an authorised foam type leak detection product for this purpose Fit the casing and place the boiler into operation see box 51 54 or 55 DANGER OF FATAL ACCIDENT A All work on gas pipework and gas fitting components must be carried out by a company registered and authorised for this purpose Take the boiler out of operation and close the gas tap see box 43 44 46 or 47 Open some of the radiator valves We reserve the right to make technical modifications Reset the digital pressure gauge to zero CAUTION LS Throughout the measuring operation keep the pressure gauge in the same position horizontal or vertical in which it was reset to zero Loosen by two turns the screw on the burner pressure measurement nipp
32. boilers with hot water supply hot water available no heating operation Applies to boilers without hot water supply no heating operation Applies to boilers with hot water supply hot water available no heating operation The heating circuit is warmed up without a heat requirement Pump over run time Heating system factory default setting 5 minutes for details of hot water and service mode see box 5 The target room temperature may not be reached Heat request but no respons of the boiler Recycling phase The fan runs for 15 seconds at about 60 of maximum speed Extraction of residual fumes in boiler The target room temperature may not be reached The target room temperature may not be reached No heating operation and no hot water 1 This error code may deactivate again automatically after a specific time without reset Heating and hot water are now available once more 2 In the event of this malfunction the pump is started up and remains in continuous operation in order to minimise the possibility of the heating system freezing up We reserve the right to make technical modifications 18 Diagnosis box 21 box 21 box 22 box 23 box 24 box 22 box 25 box 285 box 26 box 27 box 28 box 27 Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 b J in Display code
33. detected an insufficient ionisation current after four startup attempts Locking boiler fault code Is the heating system propane gas fired step 3 Ensure that no nitrogen remains in the gas tank or gas flow pipes step 63 You should also consult your gas utility company Check whether the gas tap is open see box 59 Is the gas tap open step6 step 5 Open the gas tap see box 59 step 63 Check the static and working gas pressure see box 230 Are the static and working gas pressures correct step 14 step 8 Check to see if there is a restriction in the pipework between the gas tap and gas valve Is there a restriction step 10 step 11 Deal with restriction step 63 Check for restrictions in the remaining section of the gas flow pipe Is there a restriction gt step 13 step 38 Deal with restriction step 63 Has the gas flow pipe been bled of air step 16 step 15 Vent the gas flow pipe of air see box 239 step 62 Check to see if the glow ignitor activates with the operating code see box 130 Does the glow ignitor activate with the operating code OL step 21 step 18 We reserve the right to make technical modifications Buderus Ltd http Awww buderus domestic co uk 32 Servicing manual Gas condensing boiler
34. in ready mode There is a current heat requirement but too much energy has been supplied Standby for operation The boiler is in ready mode There is no current heat requirement Ignition phase The gas valve is activated Startup phase The boiler starts up after activation of the mains power supply or completion of a system reset This code is displayed for a maximum of 4 minutes Operating phase The flow sensor has detected that the current CH flow temperature is higher than the temperature entered at the control unit or that it is higher than the CH flow tempera ture calculated according to heating requirements or that itis higher than the CH flow temperature calculated for the purposes of hot water supply Fault No The flow sensor or safety sensor has detected that the 1 current CH flow temperature is higher than 95 C Fault Yes The flue gas STL fume monitoring device has detected 2 a temperature higher than 105 C The flue gas STL is opened Fault No The flow sensor and safety sensor have after burner 1 startup not detected any temperature increase in the heating water or they have determined that the temperature difference between The flow sensor and safety sensor is too high Other symptoms No indication on DBA control panel display Hot water mode to warm start No or insufficient hot water radiators convectors etc may be heated without current heat requirement Applies to
35. mode to warm start ol Hot water mode warm start setting or hot water requirement Heating mode or heating requirement TH Summer operation no heating mode hot water only Display readings Factory Key to display reading default setting Display readings cy Current CH flow temperature Control panel settings Key to display setting Service mode Service mode partial load Service mode full load End service mode or wait for 30 minutes Hotwatermod r Hot water supply to ECO Only applies to combi boilers 1 rol Hot water mode to warm start DHW temperature 40 60 q Heating mode ON Heating mode 7 TIT Heating mode OFF CH flow temperature flashing 1 When it appears on the display at a system boiler please connect a link between terminal 3 and 4 on the back side of the DBA control panel hot water cylinder sensor or make sure that the hot water cylinder sensor is fitted securely box 19 Displaycodes Normaly you see the current CH flow temperature By pushing the A button you will see the current operation code Blocking The boiler stops heating and will wait until the blocking is solved Locking Displaycode is blinking and also a blinking wrench F appears The boiler stops heating and the pump is still running The only
36. pump Clean the pump impeller wheel box 100 Refit the top section of the pump Fill and vent the heating system see box 52 to 58 Fit casing see box 51 box 101 Replace the pump DANGER OF FATAL ACCIDENT due to electric shock Take the boiler out of operation and drain the heating system see box 43 44 47 45 49 or 50 Remove the power supply plug of the pump see box 92 We reserve the right to make technical modifications Loosen the union nuts item 1 at the top and side of the pump Remove the pump CAUTION Fit new flat sealing rings when installing the new pump Install the new pump Insert the power supply plug of the pump fill and vent the heating system of air and put the boiler into operation see box 57 to 60 Fit casing see box 51 box 104 Check the flow safety and DHW temp sensors applies to external cylinder only Put the boiler into operation see box 54 or 55 Open the hot water tap and wait for the boiler to start up then gradually close the hot water tap to bring the CH flow temperature to over 80 C Take the boiler out of operation and remove the casing see box 43 44 or 47 Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 47 Pull out the plug of the flow NTC sensor Pull out the plug of the safety senso
37. 0v between the two Replace RTH converter Junction box Continuity reconnect the cables to terminals 1 amp 2 and check the connections between the terminals and the DBA Is the volt free connection to the RTH converter Junction box fitted correctly Yes No Check to ensure that the connections of the external control unit are attached to terminal 1 and 2 of the connection block indicated by a clock inside a rectangle see box 286 and box 285 item 3 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C e Issued 02 2006 box 42 gt box 41 step 33 gt box 42 gt step 36 step 39 step 45 step 38 box 42 step 41 step 42 box 42 step 47 step 44 box 42 box 41 step 47 box 42 step 4 step 3 box 42 step 6 step 8 Buderus Ltd http www buderus domestic co uk step 7 step 8 step 9 step 10 step 1 step 2 step 3 step 4 step 5 step 6 step 7 step 8 step 9 step 10 step 11 step 1 step 2 step 3 step 4 step 5 step 6 step 7 We reserve the right to make technical modifications Is there a permanent link between terminal 1 and 2 on the volt free connecter Check the cable connection between the RTH converter Junction box and terminal 1 and 2 on the DBA Check the external cable connections and control devices Has the malfunction been repaired The swi
38. 2006 71 Fill the heating system vent it of air open the gas tap and place the boiler into operation see box 59 or 52 to 58 Take the boiler out of operation see box 43 44 or 47 Close the cold water tap Drain the heating system see box 48 to 51 Open hot water tap a Uo Remove condensate trap Remove the plate heat exchanger Remove syphon We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 72 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 box 274 Fit new plate heat exchanger Renew the four O rings if necessary Refit the plate heat exchanger and secure with the two screws Open the cold water service valve Open the hot water tap in order to clean the new plate heat exchanger inside Close the hot water tap Fill the heating system see box 52 Fit the casing and place the boiler into operation see box 51 54 or 55 box 275 Replace the pressure relief valve Take the boiler out of operation and drain the heating system see box 48 to 50 Remove the stop spring item 2 of the pressure relief valve Remove the pressure relief valve item 1 in the direction of the arrow box 277 Release the pressure relief valve from the sectio
39. 29 490 5 23 462 55 3 271 10 18 787 60 2 760 15 15 136 65 2 339 20 12 268 70 1 990 25 10 000 75 1 700 30 8 197 80 1 458 35 6 754 85 1 255 40 5 594 90 1 084 45 4 656 95 940 50 3 893 100 817 DANGER OF FATAL ACCIDENT A due to electric shock CAUTION L amp S To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection Take the boiler out of service and tip the DBA control panel forwards see box 43 44 47 or 63 Loosen the six screws and remove the rear section see box 70 Pull out the plugs of the flow NTC sensor and safety sensor see box 105 We reserve the right to make technical modifications 0000 88 000000000 10 at a JP3 Key to terms 1 Flow NTC sensor 2 Safety sensor Set multimeter to measure resistance Check the cables of the flow NTC sensor and safety sensor for breaks The electrical resistance measured at each individual wire must be approximately 0 Q Check the cables of the flow NTC sensor and safety sensor for internal short circuits The level of electrical resistance measured between two wires must be infinitely high Measure the electrical resistance of the flow NTC sensor and check the earth ground connection of the safety sensor This must be infinitely high Buderus Ltd http www buderus d
40. 62 step 58 Check the ionisation electrode and replace as required see box 155 step 62 step 59 Temporarily disconnect the flue gas pipework from the top of the boiler Run the boiler at low mode see box 13 Check to see if the fault has been rectified step 60 Has the malfunction been repaired Yes step 61 No step 62 step 61 The cause of the fault lies in the flue gas system Take the boiler out of operation box 42 step 62 Switch the boiler off and then on again at the operating switch step 63 Is the error code still displayed Yes step 64 No box 42 step 64 Has an error BH reoccurred Yes step 66 No step 65 step 65 Interpret the display code with box 20 and deal with the fault step 66 Has the entire table box 36 been covered Yes box 41 No step 1 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 34 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 step 1 step 2 step 3 step 4 step 5 step 6 step 7 step 8 step 9 step 10 step 11 step 12 step 13 step 14 step 15 step 16 step 17 step 1 step 2 step 3 step 4 step 5 step 6 We reserve the right to make technical modifications The system has detected an ionisation current before burner startup H r Locking boiler fault code EN ZININ Is the ionisation cu
41. 7214 8900 02 2006 GB EN For the installer Servicing manual Gas wall hung Boiler condensing Buderus 500 24 S Buderus 500 24 C Buderus 500 28 C enchmark budaerus Please read thoroughly before attempting fault diagnosis C The boiler meets the basic requirements of the appropriate standards and directives Conformity has been substantiated by the proper documents which together with the declaration of conformity are filed with the manufacturer Subject to technical modifications Constant development efforts may result in minor deviations in illustrations functional steps and technical data Updating the documentation If you have suggestions for improvement or have found discrepancies please do not hesitate to contact us We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 2 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 qT G n ral spesecen ce ss ie ee eee eed eke 4 2 Servicing manual user guide 10 3 Operation recitere tas inea eaa ieS 11 4 FUNCUON T E eee ee 14 5 Symptoms se ccc eee ee eee eee 17 6 Diagnosis 266 sa bei eee vee eat 21 T SACHONS 2 Pete eee dis oot ee ees 38 8 Appendix 20 eee eee eee eee 76 OD INGO X sees ciate eee ree ie an 7 G C Aplliance No Buderus 500 24 S 41 110 24 Buderus 500 24 C 41 110 04 Buderus 500 28 C 41 110 03
42. 90 M Measure and adjust the gas air ratio 04 box 233 Measure the gas input pressure static and dynamic box 230 Measure the ionisation current 0 0 000004 box 143 We reserve the right to make technical modifications Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 R Removal of casing 0 0 cece eee eee eee eee box 47 Replace plate heat exchanger 0 00e0eee box 269 Replace the automatic air vent 00000 box 242 Replace the Buderus 24V AC external 3 way valve drive mechanism 00 00 esse box 224 Replace the Buderus 24V AC external 3 way valve servomotor 0 0 c cee eee eee box 217 Replace the burner 0 cee cece cence tenes box 245 Replace the DBA control panel 000 box 281 Replace the flow NTC sensor and or safety sensor box 116 Replace the flue gas STL eee eee eee eee box 129 Replace the gas valve 0 ce cee box 174 Replace the glow ignitor 0 00 e esses box 140 Replace the internal 3 way valve 0000 box 203 Replace the internal 3 way valve drive mechanism box 198 Replace the pressure relief valve 0000 box 275 Replace the pump 0 c cece eee eee box 101 Replace the sight glass 0 0 c cece cece box 253 Replace clea
43. Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 step 18 step 19 step 20 step 21 step 22 step 23 step 24 step 25 step 26 step 27 step 28 step 29 step 30 step 31 step 32 step 33 step 34 step 35 step 36 step 37 step 38 step 39 step 40 step 41 step 42 step 43 step 44 step 45 step 46 We reserve the right to make technical modifications Check the power supply cable of the glow ignitor see box 137 Is the power supply cable in full working order Replace the cable loom or the affected part thereof Check the electrical resistance of the glow ignitor see box 134 Is the electrical resistance of the glow ignitor in order Replace the glow ignitor see box 140 Place the boiler in full load operation see box 13 and check whether the glow ignitor activates with the operating code OL Does the glow ignitor activate with the operating code OE Connect a digital pressure gauge see box 233 and 234 Open the gas cock and place the boiler into operation see box 59 or box 13 Check whether the gas valve opens with the operating code OL Does the gas valve open with the operating code OL Check the plug and socket connection on the gas valve see box 161 Is the plug and socket connection in full working order Reconnect the plug and socket connection at the gas valve Check whether the gas valve receives power wi
44. Detach the stop spring of the flow NTC sensor by pulling in the direction of the arrow Remove the flow NTC sensor Fit the corresponding new sensor Fill the heating system vent it of air and place the boiler into operation see box 52 to 58 Buderus Ltd http www buderus domestic co uk 50 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Take the boiler out of operation see box 43 44 or 47 pS a K Remove both plugs of the flue gas STL Set multimeter to measure resistance Check the electrical resistance of the flue gas STL Check the temperature of the flue gas at the test point on the flue pipe Compare the flue gas temperature reading with the measured electrical resistance see box 124 Flue gas STL Temperature Status Resistance in Q lt 105 C closed 0 gt 105 C open infinitely high Insert both plugs at the flue gas STL and fit the cover on the test point of the flue pipe Put the boiler into operation see box 51 54 or 55 We reserve the right to make technical modifications DANGER OF FATAL ACCIDENT A due to electric shock Take the boiler out of service and tip the DBA control panel forwards see box 43 44 47 or 63 Loosen the six screws and remove the rear section see box 70 Remove both plugs of the flue gas STL see box 121 eo0o00000000 Set multime
45. If there has been a power cut The startup load on the boiler is 49 for the first 13 seconds for the purposes of flow monitoring It is then increased or decreased accordingly The symbol 6 lights up Is the temperature in the plate heat exchanger higher than the temperature entered via the DBA control panel Is the CH flow temperature 46 C higher than the preset DHW temperature and or higher than 93 C O4 The gas valve is closed and the burner is shut down The symbol 6 goes out The fan stops after 30 seconds Is the CH flow temperature lower than the preset DHW temperature plus 35 C The gas valve is closed and the burner is shut down The symbol 6 goes out Start of pump over run time via the cylinder Start of pre purge phase 10 seconds The fan stops OH The pump stops The 3 way valve turns to the heating mode setting for two seconds The symbol l or el goes out Is there a current heat requirement from the room temperature controller The symbol TI lights up OL The fan runs at 49 of capacity The pump is started up The glow ignitor is activated for seven seconds OL Ignition phase The gas valve is opened Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes
46. Locking boiler fault code Check the plug and socket connection of the gas valve see box 161 Is the plug and socket connection in full working order Reconnect the plug and socket connection see box 161 Measure the cable between the gas valve and DBA control panel see box 164 Is the cable correctly connected and free of damage Replace the cable loom or the affected part thereof Measure the resistance of the gas valve coils see box 171 Is the resistance correct box 41 step 9 Replace the gas valve see box 174 box 42 Bad electrical contacts circuit board or EEPROM KIM of DBA control panel defective Check the contacts on the circuit board of the DBA control panel by pushing fully home the plug and socket connections on the board check and deal with any other contact problems with plug and socket connections Switch the boiler off and then on again at the operating switch Is same fault warning message still displayed step 4 step 8 Check the plug and socket connection on the EEPROM KIM see box 284 Has the DBA control panel been replaced step7 step 6 Replace the DBA control panel see box 281 step 2 Contact Buderus see on the back of this manual Has a new fault occurred z step9 gt box 42 Interpret the fault code now displayed in box 20 and deal w
47. TE CIJ Notes relating to domestic hot water The domestic hot water service must be in accordance with BS 5546 and BS 6700 The boilers are suitable for connection to most types of washing machine and dishwasher appliances When connecting to suitable showers ensure that a The shower is capable of accepting mains pressures and temperatures up to 65 C b The shower is ideally thermostatic or pressure balancing Where temporary hardness exceeds 150 mgl litre it is recommended that a proprietary scale reducing device is fitted into the boiler cold supply with the requirements of the local water company CAUTION A Provision must be made to accommodate the expan sion of DHW contained within the appliance where a back flow prevention device is fitted BS 67989 5 4 3 Safe handling of substances No asbestos mercury or CFCs are included in any part of the boiler and its manufacture We reserve the right to make technical modifications Hazard definitions A DANGER A Indicates the presence of hazards that will cause severe personal injury death or substantial property damage WARNING A Indicates the presence of hazards that can cause severe personal injury death or substantial property damage N CAUTION amp Indicates presence of hazards that will or cause minor personal injury or property damage G NOTICE UJ Indicates special instructions on installation operation or maintenance th
48. al storage type water that might be fitted Replace the turbine flow meter or DHW temperature sensor of any external storage type water heater that might be fitted Check the cable of the turbine flow meter see box 112 or cable of the DHW temperature sensor of any external storage type water heater that might be fitted Is the cable correctly connected and free of damage Replace the cable loom or the affected part thereof Check to ensure that the boiler starts up to supply hot water see box 15 Does the boiler start up Interpret current display codes box 20 and deal with fault Check to ensure that the tap flow rate is correctly adjusted see box 180 Is the tap flow rate correctly adjusted Correctly adjust the tap flow rate see box 180 Is an internal 3 way valve fitted Check the movement of the servomotor of the Buderus 24V AC external 3 way valve see box 211 Does the servomotor of the Buderus 24V AC external 3 way valve move correctly Check the movement of the servomotor of the internal 3 way valve see box 181 Does the servomotor of the internal 3 way valve move correctly Check to ensure that the the Buderus 24V AC external 3 way valve has been fitted correctly see box 227 Has the Buderus 24V AC external 3 way valve been fitted correctly Fit the Buderus 24V AC external 3 way valve in the correct way see box 227 Check the drive mechanism of the internal 3 way valve see box 195 Is the drive
49. and socket connection see box 78 item 2 box 42 Check tacho cable of fan see box 73 Is the tacho cable in full working order step 7 step 6 Replace the tacho cable box 42 Check to ensure that the mains voltage at the earthed grounded plug is between 195V and 253V AC Is the mains voltage sufficient gt gt step 10 step 9 The cause of the fault lies in the electrical system box 42 Check to see if there is a restriction in the fan burner heat exchanger or flue gas system Is there a restriction gt step 12 step 13 Deal with restriction box 42 Check to see if there is a second fan in the flue gas pipe or air inlet system Is a second fan fitted gt step 15 step 16 Take second fan out of service box 42 Check to see if the fan impeller has come loose at the motor spindle see box 76 Has the fan come loose gt step 18 step 19 Replace fan see box 76 Has the malfunction been repaired gt gt box 42 gt box 41 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk e a u 30 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 C D The flow NTC sensor has detected a temperature of over 105 C Locking boiler fault code Check the fl
50. ank sensor 2 only for Buderus 500 24 C and 500 28 C safety sensor 24Vac flow sensor tT E30Vac Buderus controller RTH converter or ON OFF controller o OMONONONOAORO hot water tank sensor o OUOHOHO o sensor 24VAC 5 earth 6 o Turbine 2 hot water o oUoUo 3 way valve 7 24 VAC 0 VAC switch contact 00000000000000000 3 way valve QO Buderus 24V AC external gas valve od D g Q 5 o 8 s x 8 faa o 3 Q flue gas thermostat er to S ionisation electrode High voltage 6 OOF Ne Mains 230 VAC 50 Hz glow ignitor m oo0oo0oo0oo0oo0o a A N a 230 VAC 50 Hz We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 76 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 A Adjust the output flow rate applies to combination BOES ONY 46 2 6 32 sake Petar a cates ut Shee whee hi et box 180 C Check and replace the ionisation e
51. anual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 39 1 Turn the operating switch on the boiler to position 1 ON item 1 Fill the heating system to a pressure of approximately 1 5 bar then close the filling loop Vent all the air vent points in the heating system working from bottom to top in order to allow all air in the heating system to escape Loosen by two turns the vent screw item 1 on the front of the pump CAUTION Water will also squirt out We reserve the right to make technical modifications Vent the pump CAUTION Correct venting of the pump will help ensure that it runs for its specified service life The sliding bearing which is located behind the vent screw is lubricated with heating system water Once the heating system has been completely purged of air check the pressure at the analogue pressure gauge If the pressure is lower than 1 0 bar the boiler should be topped up as described above Close the water tap In the case of system boilers Close the filling loop of the boiler see box 50 item 2 Remove the hose Fit the sealing cap to the filling and draining cock In the case of combination boilers Close the filling loop Remove the hose Fit casing see box 51 Configure target adjustments using the Settings menu on the DBA control panel of the boiler see box 61
52. as detected an insufficient ionisation current Fault The system has detected an ionisation current before burner startup Fault An ionisation current has been measured as soon as the burner shuts down Fault The flame goes out during the operating phase Fault The power supply was shut off during a crucial breakdown Operating phase Display test during startup phase The code is displayed for a maximum of 1 second Fault The DBA control panel is defective Fault The contacts of the gas valve have been broken Fault The DBA control panel is defective Fault The contacts of the gas valve have been broken Fault The DBA control panel is defective Reset required No 1 No 1 Yes 2 Yes 2 Yes 2 Yes 2 Yes 2 Yes 2 Yes 2 No 1 Yes 2 Yes 2 Yes 2 No 1 Yes 2 Yes 2 Yes 2 Yes 2 Yes 2 Yes 2 Other symptoms No hea No hea No hea No hea No hea No hea ing operation and no hot water ing operation and no hot water ing operation and no hot water ing operation and no hot water ing operation and no hot water ing operation and no hot water No heating operation and no hot water No heating operation and no hot water No heating operation and no hot water No heating operation and no hot water No heating operation and no hot water No hea No hea No hea No hea No hea
53. at are important but not related to personal injury or property damage Abbreviations AV Air Vent BCT Buderus cylinder thermostat BDV Buderus diverter valve CB Connection Block CH Central Heating CHF Central Heating Flow CHR Central Heating Return CT Cylinder Thermostat CWDO Condensate water drainage outlet DHW Domestic Hot Water DV Diverter Valve E Earth L Live LSV Lock Shield Valve MCW Mains Cold Water N Neutal JB Junction Box RTH Relay PL Permanent Live Prog Programmer PRV Pressure relief valve safety valve RT Room Thermostat RV ModuLink 250 RF Receiver T Timer TRV Thermostatic Radiator Valve WC Wiring Centre ZV Two Port Zone Valve Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 5 Buderus Unit 500 24 S 500 24 C 500 28 C Hot water capacity combination boilers kW 5 7 28 5 6 0 24 0 5 7 28 5 with external tank Rated thermal load for CH kW 5 7 23 0 5 7 23 0 5 7 23 0 Rated thermal load for preparing DHW kW 5 7 28 5 5 7 23 0 5 7 28 5 Rated heating capacity for system temperature modulating from 30 to 100 Heating curve 75 60 C kW 5 3 22 0 5 3 22 0 5 3 22 0 Heating curve 40 30 C kW 6 0 24 0 6 0 24 0 6 0 24 0 Seasonal efficiency SEDBUK for natural gas 90 3 90 3 90 3 for pro
54. ature is correctly adjusted see box 14 step 17 Is the CH flow temperature adjusted to a high enough setting step 18 Adjust the CH flow temperature to a higher setting see box 14 step 19 Is the CH flow temperature of the boiler sufficient to heat the building step 20 Install a larger boiler step 21 Is there a hot water supply step 22 Is an internal 3 way valve fitted step 23 Check the movement of the servomotor of the internal 3 way valve see box 181 step 24 Does the servomotor of the internal 3 way valve move correctly step 25 Check the drive mechanism of the internal 3 way valve see box 195 step 26 Is the drive mechanism working correctly step 27 Replace the drive mechanism of the internal 3 way valve see box 198 step 28 Check the actuation of the servomotor of the internal 3 way valve see box 185 step 29 Does the servomotor of the internal 3 way valve start up correctly We reserve the right to make technical modifications Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No step 5 step 4 box 42 step 11 step 7 step 9 step 10 box 42 box 42 step 13 step 15 step 16 step 14 box 42 box 42
55. ble of the fan for breaks The electrical resistance measured at each individual wire must be approximately 0 Q Check the tacho cable of the fan for internal short circuits The level of electrical resistance measured between two wires chosen at random must be infinitely high Connect the tacho cable plug Refit the DBA control panel following the above procedure in reverse order Refit the casing and place the boiler into operation see box 51 53 54 or 55 We reserve the right to make technical modifications DANGER OF FATAL ACCIDENT A due to electric shock DANGER OF FATAL ACCIDENT amp All work on gas pipework and gas fitting components must be carried out by a company registered and authorised for this purpose A NOTE _ _J Please observe the fitting instructions supplied with the fan Take the boiler out of operation and close the gas tap see box 43 44 46 or 47 Pull out the power supply plug of the gas valve item 1 Loosen the union nut item 2 Detach the air silencer tube item 3 Pull out both fan plugs item 2 Pull out the glow ignitor plug item 3 Pull out the ionisation electrode plug item 1 Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 43 a ass i A Twist drawing 1 the fan in the direction of
56. box 104 Are the flow NTC sensor and safety sensor functioning correctly step 10 step 9 Replace the flow NTC sensor or safety sensor see box 116 Check the cables of the flow NTC sensor and safety sensor see box 112 Are the cables in order gt step 13 step 12 Replace the cable loom or the affected part thereof gt box 42 Check the pump see box 89 to 100 Is the pump working correctly gt box 41 step 15 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 31 re Peares box 34 step15 Replace the pump see box 101 box 42 box 35 The contacts of the flow NTC sensor or safety sensor are broken Locking boiler fault code Check the flow NTC sensor and safety sensor see box 104 Are the flow NTC sensor and safety sensor functioning correctly Replace the flow NTC sensor and safety sensor see box 116 Check the cable of the flow NTC sensor and safety sensor see box 112 Are the cables in order gt box 41 step 6 Replace the cable loom or the affected part thereof gt box 42 The system has detected an insufficient ionisation current during the ignition phase Blocking boiler fault code The system has
57. cal modifications Buderus Ltd http www buderus domestic co uk 8 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Item 1 lonisation electrode N WARNING Glow ignitor 2 DANGER OF FATAL ACCIDENT Item 2 FROM EXPLOSIVE FUMES Item 3 Automatic air vent If you smell gas Item 4 Safety sensor There is a danger of explosion Item 5 Clamp for heat exchanger cover No naked lights No smoking DO NOT use a naked Item 6 Plate heat exchanger light to detect possible leaks o DO NOT operate any device that is likely to produce ltem 7 Condensate trap sparks Item 8 Flow NTC sensor DO NOT operate electrical switches of any kind Item 9 DHW flow regulator including telephones plug in devices and j 10 P doorbells fei 07 Eressure gauge Shut off the gas supply at the main valve Item 11 Concentric flue gas adaptor Open doors and windows Item 12 Fan Warn other occupants of the building but DO NOT use the house intercom or doorbells Contact the gas supplier from a telephone located outside the building f you detect an audible gas leak evacuate the building immediately prevent other persons from entering and notify the police and fire service immediately from a telephone OUTSIDE the building Item 13 Frame Item 14 Gas Air unit ltem 15 Sight glass ltem 16 Gas valve Item 17 Heat exchanger Item 18 Gas supply pipe Item 19 Identification plate
58. cing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 step22 step23 step24 step25 step26 step27 step28 step29 step30 step31 step32 step33 step34 step35 step36 step37 step38 step39 step40 step41 step42 step43 step 44 step45 step46 step47 step48 We reserve the right to make technical modifications Is the current CH flow temperature lower than 7 C frost protection The pump is run for 10 seconds in order to prevent it from seizing up Have 10 seconds elapsed Is the plate heat exchanger triggered and or is the temperature in the external storage type water heater at least 5 C below the temperature set at the DBA control panel Is there a current heat requirement from the room temperature controller Is the current CH flow temperature lower than 7 C frost protection The symbol l or T for hot water mode on the DBA control panel display lights up OL The fan runs at 49 of capacity The 3 way valve turns to the hot water setting for two seconds The glow ignitor is activated for two seconds OL Ignition phase The gas valve is opened The glow ignitor is activated for one second followed by alternating half second periods of inactivity and activity until five seconds have elapsed Does the ionisation current exceed 1 4 pA microamperes within 5 seconds H The boiler is in hot water mode
59. d step 15 Is the by pass valve working correctly Yes No We reserve the right to make technical modifications 28 The flow NTC sensor or safety sensor has detected that the current CH flow temperature is higher than 95 C Blocking boiler fault code The flow NTC sensor and safety sensor have not after burner startup detected any temperature increase in the heating system water or the temperature difference between the flow NTC sensor and safety sensor is excessive Blocking boiler fault code The flow NTC sensor has detected a temperature increase in the heating system water of more than 5 C sec Blocking boiler fault code The flow NTC sensor and safety sensor have detected a CH flow temperature of over step 9 box 15 box 42 box 41 step 12 step 3 step 2 step 5 step 4 step 7 step 6 box 42 step 10 step 9 box 42 step 14 step 13 box 41 step 14 Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 SC box 27 step 16 Replace the by pass valve box 42 box 28 The flue gas STL fume monitoring device has detected a temperature higher than 105 C The flue gas STL is open Locking boiler fault code Check to ensure that the restrictor baffle has been installed as per box 261 item 1 Has the res
60. e gas valve internal electrical resistance box 171 Check the gas valve power supply plug box 161 Check the glow ignitor activation 0 box 130 Check the glow ignitor power supply cable box 137 Check the glow ignitor resistance 00 box 134 Check the internal 3 way valve activation box 185 Check the internal 3 way valve drive mechanism box 195 Check the internal 3 way valve movement of the servomotor box 181 Check the internal 3 way valve power supply cable box 191 Check the ionisation circuit earth ground lead box 160 Check the ionisation electrode cable box 151 Check the ionisation electrode short circuits box 148 Check the pressure control valve 0 0s eee ee eee box 85 Check the pump activation 0 0 0 cee e eee eee box 91 Check the pump mechanical restrictions box 89 Check the pump power supply cable box 95 Check the pump soiling 0 0 0 0 c eee eee box 97 Check replace fuses 1 cece eee eens box 62 D Draining the system 0 c cee box 48 F Filling the system and venting it of air 0 box 52 l Initialst rtuUp u i ite a a A da i eed pad box 59 Internal 3 way valve replace the servomotor box 1
61. e internal 3 way valve see box 200 CAUTION 4 i Note that water will squirt out when the internal 3 way valve is removed Have a bucket and a supply of dry cloths to hand We reserve the right to make technical modifications Replace the housing of the 3 way valve Refit all components following the above procedure in reverse order Fill the heating system vent it of air and place the boiler into operation see box 52 to 58 Put the boiler into operation see box 54 and 55 Adjust the hot water in the Settings menu on the DBA control panel of the boiler to 60 C see box 61 Open a hot water tap Check to see if the servomotor of the Buderus 24V AC external 3 way valve during the operating code UL rotates from the setting for heating mode position 1 to the position for hot water mode position 2 Close the hot water tap Check to see if the servomotor runs back again Adjust the hot water in the Settings menu on the DBA control panel of the boiler see box 61 Buderus Ltd http www buderus domestic co uk 62 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 CAUTION A To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection Take the boiler out of operation see box 43 44 or 47 Remove the power supp
62. easure direct current Measuring range Microamperes pA Connect the multimeter in series the ionisation circuit Put the boiler into service mode see box 54 55 or 13 Check to see if the ionisation current during service mode operating code LLa gt 5 pA micro amperes and with operating code H gt 25 pA The value is O zero or between 1 3 and 50 pA Take the boiler out of operation see box 43 or 44 Detach the multimeter Connect the plug of the ionisation electrode Turn the operating switch on the boiler to position 0 see box 55 Put the boiler into operation see box 51 54 or 55 Take the boiler out of operation see box 43 44 or 47 Loosen the plug in connection of the ionisation electrode see box 144 Ss Set multimeter to measure resistance Take a reading at the electrode to check whether there is a possible short circuit between the ionisation electrode and earth ground The electrical resistance between the ionisation electrode and earth ground must be infinitely high We reserve the right to make technical modifications Connect the plug of the ionisation electrode Put the boiler into operation see box 51 54 or 55 DANGER OF FATAL ACCIDENT ZLN due to electric shock Take the boiler out of service and tip the DBA control panel forwards see box 43 44 47 or 63 Loosen the six screws and remo
63. ected part thereof Replace fuse again see box 62 Turn the operating switch on the DBA control panel of the boiler to position 0 OFF see box 43 Connect the power supply plug of the pump in reverse Turn the operating switch on the DBA control panel of the boiler to position 1 ON see box 55 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 step 4 step 3 box 42 step 7 step 6 box 42 step 10 step 9 box 42 step 22 step 21 box 42 box 41 step 15 box 42 step 17 step 22 step 21 step 27 step 24 step 27 step 26 box 42 Buderus Ltd http www buderus domestic co uk 21 step 30 step 31 step 32 step 33 step 34 step 35 step 36 step 37 step 38 Is there any indication on the DBA control panel display Yes step 33 No step 31 Replace the pump see box 101 step 32 Replace fuse again see box 62 step 33 Turn the operating switch on the DBA control panel of the boiler to position 0 OFF see box 43 Connect the power supply plug of the fan in reverse Turn the operating switch on the DBA control panel of the boiler to position 1 ON see box 55 Is there any indication on the DBA control panel display Yes box 42 No step 37 Replace fan see box 76 step 38 Replace fuse again see box
64. ed Check the working gas input pressure or analyse the exhaust gas accordingly box 230 Exit full load service mode gt step 12 step 10 Press the button once or wait for service mode to expire after 30 minutes Service mode is deactivated step 1 box 14 Settings menu 24 Current CH flow temperature in C See also box 17 Open Settings menu step 3 step 1 Press the button once gt step 4 Is boiler a combination boiler with warm start step5 step 9 F r r l el Configured hot water mode As soon as F rit is displayed you can verify the current hot water mode or adjust it as required See also box 18 Adjust configured hot water mode step 7 step 8 We reserve the right to make technical modifications Buderus Ltd http Awww buderus domestic co uk 12 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 step 7 step 8 step 9 step10 step11 step12 step13 step14 step15 step16 step17 step18 step19 step20 step21 step22 We reserve the right to make technical modifications Use single or multiple operation of the and A buttons to activate and disable hot water mode Prt r l Hot water mode to ECO F rA ol Hot water mode to warm start Press the button once
65. ensure that there is a 230V AC power supply at the mains switch Is there a 230V AC supply at the mains switch Yes No Deal with any problem in the electrical system Measure the resistance of the 230V AC power supply cable Is the resistance of the 230V AC power supply cable within the specified limits Yes No Replace the cable loom or the affected part thereof Use a multimeter to check the fuse on the inside of the DBA control panel see box 62 to 65 Is the fuse working correctly Yes No Replace fuse see box 62 Is there any indication on the DBA control panel display Yes No Turn the operating switch on the DBA control panel of the boiler to position 0 OFF see box 43 Disconnect the following boiler components from the electrical power supply pump see box 92 fan see box 71 item 1 Check the fuse again for correct functioning Use a multimeter to check the fuse on the inside of the DBA control panel see box 62 Is the fuse working correctly Yes No Replace fuse again see box 62 Turn the operating switch on the DBA control panel of the boiler to position 1 ON see box 55 Is there any indication on the DBA control panel display Yes No Use a multimeter to check the power supply cables of the pump box 95 the fan box 69 and the glow ignitor box 137 for signs of short circuiting Are the cables in order Yes No Replace the cable harness or the aff
66. ep 47 step 46 step 62 Buderus Ltd http www buderus domestic co uk 33 step 47 The following components must be checked for soiling damage and or correct installation condensate trap and syphon see box 256 combustion air inlet pipework air silencer pipework seal between the Venturi and fan Venturi see box 86 gas injector see box 83 item 1 fan connection between the fan and burner burner heat exchanger system of flue gas pipe and air inlet pipeworks pressure control valve see box 85 earth ground lead of ionisation circuit see box 160 step 48 Are the above mentioned components clean free of damage and or correctly intalled Yes step 50 No gt step 49 step 49 Clean replace and or correctly install the components concerned step 62 step 50 Measure the ionisation current see box 143 step 51 Is the ionisation current in order Yes step 62 No step 52 step 52 Check the plug and socket connection between the ionisation electrode and cable loom see box 144 step 53 Is the plug and socket connection in full working order Yes step 55 No step 54 step 54 Correctly insert the plug into its socket step 62 step 55 Check the cable of the ionisation electrode see box 151 step 56 Is the wiring in order Yes step 58 No step 57 step 57 Replace the cable loom or the affected part thereof step
67. ervice the system once a year This includes an inspection of the entire system to see if it is in full working order Defects and faults must be eliminated immediately GJ NOTE CJ When instructions aren t followed warranty expires GJ NOTE UJ Condensing boilers work more efficient if the CH flow return temperature is as low as possible We reserve the right to make technical modifications Timber Framed Buildings If the boiler is to be fitted in a timber framed building it should be fitted in accordance with the Institute of Gas Engineering document IGE UP 7 1998 and BS 5440 1 Bathroom Installations This appliance is rated IP X4D The boiler may be installed in any room or internal space although particular attention is drawn to the requirements of the current IEE BS 7671 Wiring Regulations and in Scot land the electrical provisions of the building regulations applicable in Scotland with respect to the installation of the boiler in a room or internal space containing a bath or shower If the appliance is to be installed or serviced in a room containing a bath or shower then providing water jets are not going to be used for cleaning purposes as in communal baths showers the appliance can be installed or serviced in Zone 3 as detailed in BS 7671 Compartment Installations A compartment used to enclose the boiler should be designed and constructed especially for this purpose An existing cupboard o
68. g water system is a possible cause Are such items detected Yes step 13 No box 42 Place the affected components out of service box 42 Check SMa to ensure that the pre adjusted setting corresponds to the hot water bu box 14 supply to ensure that the DHW temperature is adjusted to a high enough setting see box 61 to see if the hot water supply has been shut off by the control system ModuLink 250 RF Are the adjustment settings in order Yes step 17 No step 16 Adjust the settings box 42 Check to see if the hot water mode indicator g or 1 lights up on the display see box 11 Does the hot water mode indicator e or e1 light up Yes step 25 No step 19 Check the turbine flow meter see box 104 or DWH temperature sensor of any external storage type water heater that might be fitted Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 step 20 step 21 step 22 step 23 step 24 step 25 step 26 step 27 step 28 step 29 step 30 step 31 step 32 step 33 step 34 step 35 step 36 step 37 step 38 step 39 step 40 step 41 step 42 step 43 step 44 step 45 step 46 step 47 We reserve the right to make technical modifications Is the turbine flow meter working correctly along with DHW temperature sensor of any extern
69. he boiler is routed downwards as standard but may be routed upwards behind the boiler using the wall spacing frame Subject to technical modifications As a result of our policy of constant development there may be small differences between illustrations functional steps and technical data MT D chmar BENCHMARK Log Book All Buderus gas fired boilers now include an installation commissioning and service record log book The details of the log book will be required in the event of any warranty work being requested Please complete the appropriate sections on completion of the installation and commissioning REMEMBER Please hand the log book back to the user Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 3 It is a requirement that all gas appliances are installed and serviced by a CORGI registered installer in accordance with the regulations Failure to service appliances correctly could lead to prosecution It is in your own interest and that of safety to ensure the law is complied with It is a requirement and in your own interest and that of safety that this boiler must be serviced by a CORGI registered installer in accordance with the relevant requirements of the current Gas Safety Installation and Use Regulations The Building Regulations current E E Wiring Regulations and the relevant British Standard
70. her the Buderus 24V AC external 3 way valve is correctly fitted A flow of storage type water heater B CH flow AB boiler flow Buderus Ltd http www buderus domestic co uk 64 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 DANGER OF FATAL ACCIDENT A All work on gas supply pipes and gas fitting components must be carried out by a company registered and authorised for this purpose Take the boiler out of operation and close the gas tap see box 43 44 46 or 47 Open some of the radiator valves LO Room Controller t Hot water tank sensor 24 VAC 3 way valve i e Plug in contacts Purpose Plug in contacts on DBA control of Buderus 24V 2 panel AC external 3 way valve 5 24V AC 2 6 OV AC 3 7 _ 6 Take the boiler out of operation and remove the DBA CAUTION control panel see box 43 44 47 63 or 70 The pressure gauge should be accurate to 2 decimal Put the boiler into operation see box 54 and 55 places X 00 Open hot water tap Reset the digital pressure gauge to zero Adjust the hot water in the Settings menu on the DBA CAUTION control panel of the boiler to 60 C see box 61 and box 14 Throughout the measuring operation keep the Set the multimeter to measure AC voltage pressure gauge in the same position horizontal or Minimum measuring range 40V AC vertica
71. ing see box 59 54 55 or 51 Buderus Ltd http www buderus domestic co uk 44 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Remove the fan see box 76 to box 79 Check to see if the non return valve item 5 and 6 if fitted is soiled or defective Loosen the upper nut item 2 Loosen the two lower nuts item 1 Turn the securing plate 180 counterclockwise item 3 Remove the fan part item 7 Bend the silicon seal item 4 Remove the plastic valvehousing item 5 Check the silicon valve item 6 and replace when necessary After checking refit all components in reverse order Make sure that the cam item A of the silicon valve is mounted in the correct manner A First tighten the upper nut item 2 then tighten the lower two nuts item 1 Refit all other components in reverse order then put the boiler into service see box 51 54 or 55 Take the boiler out of operation see box 43 44 or 47 Remove the air intake duct see box 77 Remove the Venturi see box 81 item 1 We reserve the right to make technical modifications i Check the article number of the Venturi against those listed in the table in box 5 Check to ensure that the correct Venturi has been fitted This is done by comparing the article numbers listed against the number on the Venturi item 1 see box 5 Check the Venturi for s
72. ing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 67 i Twist t remove Fit the new automatic air vent by following the above procedure in reverse order Fill the heating system vent it of air and place the boiler into operation see box 52 to 58 DANGER OF FATAL ACCIDENT LL due to electric shock DANGER OF FATAL ACCIDENT C2 All work on gas supply pipes and gas fitting components must be carried out by a company registered and authorised for this purpose Take the boiler out of operation and close the gas tap see box 43 44 46 or 47 Remove the power supply plug of the glow ignitor see box 131 Remove the plug of the ionisation electrode see box 144 Remove the power supply plug of the gas valve union nut and air silencer tube see box 77 Pull out both fan plugs item 1 We reserve the right to make technical modifications t Ae Remove the gas air unit along with the burner Remove the burner Buderus Ltd http www buderus domestic co uk 68 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 box 250 box 255 Fit the new burner to the gas air unit Note that a new seal Install the new sight glass Use a new seal when doing so must be fitted between the burner and gas air unit Put the boiler into operation see box
73. ing system The pump over run time via the heating system is 5 minutes Start of the post purge phase of fan 10 seconds step61 The fan stops step 13 step62 The symbol lights up step63 OL The fan starts up The pump is started up The glow ignitor is activated for seven seconds step64 OL _ Ignition phase The gas valve is opened step65 Does the ionisation current exceed 1 4 pA microamperes within 5 seconds Yes step 66 No box 36 step66 H _ The symbol 6 lights up The boiler is in heating mode step67 Is the current CH flow temperature higher than 15 C Yes step 68 No step 67 step68 The symbol lt 10 goes out step69 OH The gas valve is closed The burner is shut down The symbol 6 goes out step70 Start of pump over run time via the heating system The pump over run time via the heating system is 5 minutes Start of the post purge phase of fan 10 seconds step71 The fan stops step 13 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 16 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 sirens 5 box 16 Display icons Display indication Key to display indication Va Service mode lonisation signal flame monitoring Hot water mode ECO setting or hot water requirement Standby hot water
74. ith the malfunction We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 36 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 C C2 Fit the casing to the boiler Turn the mains switch on the DBA control panel of the boiler to position 0 OFF see box 43 Turn the mains switch on the DBA control panel of the boiler to position 1 ON see box 55 The fault is now rectified Your Buderus 500 should be working now We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 37 1 Turn the mains switch on the boiler to position 0 OFF item 1 Use a radiator key to turn the casing lock to open then remove casing box 48 Draining the system Take the boiler out of operation see box 43 44 45 46 or 47 Key to terms see box 4 CH flow DHW outlet combination boilers only Gas connection MCW inlet combination boilers only 1 2 3 4 5 CH return Close the servicing valves item 6 if fitted We reserve the right to make technical modifications Buderus Ltd http Awww buderus domestic co uk 38 Servicing manual Gas c
75. l in which it was reset to zero Plug and socket connection DBA control panel conn Loosen by two turns the screw on the gas connection 6 7 pressure measuring nipple item 1 3 6 Fit the pressure gauge to the gas connection pressure 2 5 measurement nipple item 2 Check whether with operating code UL active there is a voltage of 24 V AC atthe plug in contacts item 6 and item 7 Close the hot water tap Check whether with operating code OH active there is a voltage of 24 V AC at the plug in contacts item 5 and item 6 Fit the DBA control panel and place the boiler into operation see box 51 54 or 55 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 65 Open the gas tap see box 59 Put all other gas fired devices e g gas ovens and stoves etc out of use Check to see if static gas input pressure does not rise slowly for 2 minutes Run all other gas fired appliances e g gas ovens and stoves etc at full capacity but do not operate the boiler The static gas input pressure must be for natural gas minimum 20 mbar and for propane minimum 37 mbar Open the gas cock and place the boiler into service mode see box 59 54 55 or 13 Press the service button twice Capacity during service mode is
76. l working order Yes box 41 No step 8 Replace the cable loom or the affected part thereof gt box 42 Check tacho cable of fan see box 73 Is the tacho cable in full working order Yes step 12 No step 11 Replace the cable loom or the affected part thereof gt box 42 Check to ensure that the mains voltage at the earthed grounded plug is between 195V and 253V AC We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 29 re Peares Is the mains voltage sufficient z gt step 15 step 14 The cause of the fault lies in the electrical system gt box 42 Replace fan see box 76 Has the malfunction been repaired gt gt box 42 gt box 41 No current of air after a certain time Locking boiler fault code Attempt to rectify the fault by temporarily replacing the fan see box 76 Has the malfunction been repaired gt gt box 42 gt box 41 The fan runs too slowly or too fast Locking boiler fault code Check the plug and socket connection of the fan tacho cable This is the narrow plug see box 78 item 2 Is the plug and socket connection in full working order gt step 4 gt step 3 Reconnect the plug
77. le item 1 Connect the pressure gauge to the burner pressure measurement nipple item 2 Open the gas cock and place the boiler into service mode see box 59 54 55 or 13 Press the service button once Capacity during service mode is at Lo 25 max heating circuit capacity Wait a short time for the boiler to be adjusted downwards B A B 15 10 5 0 5 Pa 0 15 0 10 0 05 0 00 0 05 mbar C l D Key to terms A correct B false C turn anticlockwise D turn clockwise Check the gas air ratio during service mode operation The differential pressure Pgas Pair must be 5 Pa 5 Pa as indicated by the measuring device 10 to 0 Pa Buderus Ltd http www buderus domestic co uk 66 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Loosen by two turns the screw on the gas connection pressure measuring nipple item 1 Connect a long hose item 2 to the gas connection pressure measurement nipple and then run this hose out of the building Use the adjustment screw to readjust the gas air ratio if necessary item 1 e NOTE GJ The adjustment screw 4mm Allen screw is located Leave the gas cock open until no further air escapes from behind the screw on cover the hose see box 59 Close the gas cock see b
78. lectrode box 155 Check fan activation 230V AC 1 eee eee box 66 Check fan power supply cable 230 VAC box 69 Check fan tacho cable 0 cece cece box 73 Check fan and or replace 0 0 c cece eee eee eee box 76 Check gas valve electrical resistance of power SUPDIV Cabless foto ote hited aie Ae ort Al ae te RNA box 167 Check the Buderus 24V AC external 3 way valve activation 1 0 ee eee eee box 212 Check the Buderus 24V AC external 3 way valve activation 2 0 0 eee eee eee box 228 Check the Buderus 24V AC external 3 way valve drive mechanism 0 00 see eee box 221 Check the Buderus 24V AC external 3 way valve installation 0 cece eee box 227 Check the Buderus 24V AC external 3 way valve movement of the servomotor box 211 Check the Buderus 24V AC external 3 way valve power supply cable 0 000 box 220 Check the by pass valve 0 eee cece eee eee box 14 Check the flow safety and DHW temperature sensors Cables rin Shade ete ee pee Hench box 112 Check the flow safety and DHW temperature sensors applies to external cylinder only box 104 Check the flue gas STL 1 2 eee box 120 Check the flue gas STL cable 2 4 box 126 Check the gas valve activation 0c eee ee ee box 164 Check th
79. lug of the servomotor see box 186 Remove the servomotor see box 182 Fit the new servomotor by following the above procedure in reverse order Put the boiler into operation see box 51 54 or 55 due to electric shock CAUTION To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection A DANGER OF FATAL ACCIDENT L Take the boiler out of operation and remove the DBA control panel see box 43 44 47 63 or 70 Remove the power supply plug of the servomotor of the 3 way valve see box 186 ae d E JP4 r Ale wat Pog Set multimeter to measure resistance Check the power supply cable of the 3 way valve for breaks The electrical resistance measured at each individual wire must be approximately 0 Q Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 59 Check the power supply cable of the 3 way valve for internal short circuits The level of electrical resistance measured between two wires chosen at random must be infinitely high Insert the power supply plug of the 3 way valve fit the DBA control panel and place the boiler into operation see box 51 54 or 55 Take the boiler out of operation see box 43 44 or 47 Remove the ser
80. ly plug of the servomotor of the Buderus 24V AC external 3 way valve Put the boiler into operation see box 51 54 or 55 Plug in contacts Purpose Plug in contacts of Buderus 24V on DBA control AC external 3 panel way valve 2 24V AC 5 3 OV AC 6 Set the multimeter to measure AC voltage Minimum measuring range 40V AC Open a hot water tap Adjust the hot water in the Settings menu on the DBA control panel of the boiler to 60 C see box 61 Check to see if during operating code OL 24VAC is detected at plug in contacts 2 and 6 Close the hot water tap Check to see if during operating code DH 24VAC is detected at plug in contacts 2 and 3 We reserve the right to make technical modifications Insert the power supply plug of the Buderus 24V AC external 3 way valve Put the boiler into operation see box 51 54 or 55 Take the boiler out of operation see box 43 44 or 47 Remove the power supply plug of the servomotor of the Buderus 24V AC external 3 way valve see box 213 Remove the servomotor of the Buderus 24V AC external 3 way valve To release the servomotor press the release catch item 1 and twist the servomotor DANGER OF DAMAGE TO THE SYSTEM A Before removing the servomotor check to see if the Buderus 24V AC external 3 way valve is in its heating mode position and wait for the boiler display code OH
81. mechanism of the internal 3 way valve working correctly Replace the drive mechanism of the internal 3 way valve see box 198 Check the circulation for debris see box 97 Is there any debris in the pump Clean the pump see box 97 The following components must be checked for soiling and or damage combustion air inlet pipework heat exchanger flue gas pipework Are the above mentioned components clean and free of damage Clean and or replace the corresponding components Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No step 22 step 21 box 42 box 41 step 24 box 42 step 28 step 27 box 42 step 31 step 30 step 34 step 32 step 36 step 63 step 39 step 57 step 69 step 38 box 42 step 42 step 41 box 42 step 44 step 45 box 42 step 48 step 47 box 42 Buderus Ltd http www buderus domestic co uk 23 step 48 Check the standing and working gas pressures see box 230 step 49 Are the standing and working pressures correct Yes step 51 No step 50 step 50 If the standing and working gas input pressures are not detected consult your gas utility company
82. n condensate trap and syphon box 256 Replace clean the heat exchanger 0000 box 259 S Shutting down o oeaan ai a a e a e a ee ae box 43 T Technical specifications 0 eee eee box 5 V Vent the gas flow pipe 0 eee eee box 239 WwW Wiring diagram s 35 30 4 seid Caen Sees Pde Helens box 287 Buderus Ltd http www buderus domestic co uk 77 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk LEE ee a a a a Y 78 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 79 Buderus Buderus Cotswold Way Warndon Worcester WR4 9SW Telephone 01905 752 936 Fax 01905 753 130 Customer Services Tel 0870 421 5933 Technical Product Support Tel 0870 421 5944 Sales Tel 01905 752 640 Fax 01905 456 445 455 394 Returns Tel 01905 752 531 Fax 01905 455 392 Spares Tel 01905 752 576 Fax 01905 754 620 www buderus domestic co uk 721 489A 4612 02 2006
83. n of condendsate outlet pipework by pulling in the direction of the arrow We reserve the right to make technical modifications Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 box 278 Fit the new pressure relief valve and all other components by following the above procedure in reverse Fill the heating system vent it of air and place the boiler into operation see box 52 to 58 box 279 Replace the turbine flowmeter Remove the stop spring box 280 Use a screwdriver to lever out the turbine flowmeter box 281 Replace the DBA control panel DANGER OF FATAL ACCIDENT due to electric shock Take the boiler out of operation and remove the DBA control panel see box 43 44 47 63 or 70 Buderus Ltd http www buderus domestic co uk 73 a N N EN MN h Disconnect the five plugs harness item 1 JP1 JP2 JP4 and JP3 from the DBA control panel Remove the DBA control panel Fit the new DBA control panel following the above procedure in reverse order CAUTION L amp S Please ensure that the new DBA control panel is fitted with the correct KIM see box 284 The coloured stripe on the new KIM should match that of the old KIM Otherwise refit the old KIM to the new DBA control panel Fit the casing and place the boiler into operation see box 51 54
84. of boiler Item 20 Air silencer tube A WARNING L DANGER OF FATAL ACCIDENT due to electric shock Item 21 Flue gas pipe Item 22 Flue gas safety temperature limiter STL Item 23 Pump 15 50 Item 24 Pressure relief valve discharge pipe A CAUTION ltem 25 Syphon LS General information on maintenance work ltem 26 Identification plate showing gas category Item 27 Connection block GJ USER INSTRUCTIONS J Instructions for optimum usage correct adjustment of the boiler and other useful information S Item 28 DBA control panel Item 29 RTH converter junction box N CAUTION amp Use eye protection inhalation protection hearing gloves shoes etc on the right time We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 9 This document consists of various sections These in turn contain subsections boxes in the form of text or tables Subsections boxes inside text and tables are identified by a small grey box Each subsection box is assigned its own identification number These subsections boxes are divided into operating steps If an operating step involves the taking of a yes no decision the right hand side of the table indicates which subsection operating step you should proceed cross reference Section Cross reference to subsection or operating step
85. oiling Refit the Venturi and fan by following the above procedure in reverse order Refit the air silencer tube Refit the casing and place the boiler into operation see box 51 53 54 or 55 Remove casing see box 47 Remove the vent screw on the front of the pump see box 57 CAUTION A Note that water will squirt out when the vent screw is removed Have a bucket and a supply of dry cloths to hand Put the electrical system of the boiler into operation see box 54 and 55 Check to see if the pump is running The pump may become mechanically blocked if the heating system has been out of use for an extended period Insert a screwdriver and attempt to make the pump turn Use the screwdriver to turn the fan wheel in the direction of rotation shown on the identification plate of the pump Refit the vent screw to the pump Fit casing see box 51 Buderus Ltd http Awww buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 45 A DANGER OF FATAL ACCIDENT C N due to electric shock CAUTION L amp S To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection N CAUTION N Close gas valve during pump test Take the boiler out of operation see box 43 44 or 47 Set the multimeter to measure AC voltage Minimum measuring range
86. omestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 49 Hot water tank sensor Hot water tank sensor 24 VAC 3 way valve s Set multimeter to measure resistance Detach the cables of the DHW temperature sensor item 3 and 4 from the DBA control panel Measure the resistance of the cable of the DHW temperature sensor and check it for short circuits and breaks See box 112 Fit the cables of the DHW temperature sensor to the DBA control panel item 3 and 4 Insert the cables of the corresponding DHW temperature or outside air temperature sensor Fit the DBA control panel and place the boiler into operation see box 54 55 or 51 Take the boiler out of operation drain the heating system and pull out the plug of the corresponding sensor see box 43 44 47 45 47 49 or 50 We reserve the right to make technical modifications N CAUTION L Note that water will squirt out when the sensor is removed Have a bucket and a supply of dry cloths to hand Pull out the plug of the safety sensor item 1 Detach the stop spring of the safety sensor by pulling in the direction of the arrow item 2 Remove the safety sensor item 3 N CAUTION LS Note that water will squirt out when the sensor is removed Have a bucket and a supply of dry cloths to hand
87. ondensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 box 52 Filling the system and venting it of air Turn the operating switch on the boiler to position 0 OFF see box 43 Remove casing see box 47 double check s valve filling loop DHW Loosen by one turn the sealing cap on the automatic air cold return vent located on the top left hand part of the boiler Connect filling loop accessory see box 50 item 6 Open both stop valves Fill the system to a pressure of approx 1 5 bar Shut both stop valves Disconnect the filling loop Vent all radiators from air starting with the lowest radiator and working your way up to the highest point Check the pressure after venting If the pressure has dropped under 1 0 bar then top up the system as described previously Disconnect the filling loop and cap off 1 Key to terms 1 CH flow 2 DHW outlet combination boilers only 3 Gas connection 4 MCW inlet combination boilers only 5 CH return Connect the hose item 6 to the drain cock of the boiler Open the filling and draining cock and drain the heating system see box 53 Turn the mains switch to ON Fit the casing and use the radiator key to turn the casing lock to closed We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing m
88. onnection Type of flue gas connection model C1309 Cag C530 C7309 Flue gas pipe combustion air inlet mm 60 100 accessory We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 6 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Buderus Flue gas readings Condensate water quantity natural gas 40 30 C Exhaust fume mass flow rate Full load Part load Exhaust fume temperature full load Heating curve 75 60 C Heating curve 40 30 C Exhaust fume temperature partial load Heating curve 75 60 C Heating curve 40 30 C CO full load natural gas standard test gas G20 CO full load natural gas standard test gas G31 propane Standard emission factor NO Standard emission factor CO Flow pressure available for use Electrical specifications Mains connection voltage Electrical protection rating Electrical power consumption standby Electrical power consumption partial load Electrical power consumption full load Dimensions and weight of boiler height x width x depth Weight without casing Weight with casing Gas Category of gas as per EN 437 for GB Gas injector natural gas H G20 Gas injector propane P G31 Venturi article number Natural gas H Propane P Other items Pump Pump over run time Heating system default adjustments External cylinder Plate heat exchanger ECO Plate heat exchange
89. or 55 We reserve the right to make technical modifications Check the plug and socket connection on the EEPROM KIM To Boiler 0008 Q o 24Vac RTh SOSS aeAve Remove the casing lock and lower the DBA Remove the cover from the RTH converter Junction box item 1 Run the 230V power supply cable through the cable pipework Connect the 230V cable to item 1 The switch live should be connected to terminal 1 and the Neutral to terminal 2 of the 230V connection item 2 Buderus Ltd http www buderus domestic co uk 74 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 box 286 Check the junction box 0 Volt room temperature connection Remove the casing lock and lower the DBA see box 285 Remove the cover from the RTH converter junction box see box 285 item 1 Run the volt free power supply cable through the cable pipework Connect the volt free cable at position 1 and 2 of the volt free connection see box 285 item 3 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 75 box 287 Wiring diagram 1 only for Buderus 500 24 S remove the link at the connection of the hot water t
90. or runs back again Buderus Ltd http www buderus domestic co uk 58 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Fit the servomotor to the 3 way valve Insert the stop spring Adjust the DBA control panel see box 61 Fit casing see box 51 CAUTION A To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection Take the boiler out of operation see box 43 44 or 47 Pull out the power supply plug of the servomotor Put the boiler into operation see box 54 and 55 e Set the multimeter to measure AC voltage a Minimum measuring range 40V AC Use the Settings menu on the boiler DBA control panel to adjust the temperature to 60 C see box 14 or 18 Open a hot water tap Check to see if during operating code OL at plug in contacts 1 and 3 24 V AC is detected between plug in contacts 1 and 2 Close the hot water tap Check to see if during operating code DH 24 V AC is detected at plug in contacts 1 and 2 We reserve the right to make technical modifications Insert the power supply plug of the 3 way valve Put the boiler into operation see box 51 or 61 Take the boiler out of operation see box 43 44 or 47 Remove the power supply p
91. ow rate in the heating circuit Are all servicing valves and thermostat valves closed Check all servicing valves and thermostat valves for correct functioning Open all servicing valves and thermostat valves Has the malfunction been repaired z gt box 42 gt box 41 The sensor test has failed Locking boiler fault code Check the flow NTC sensor and safety sensor and their wiring for short circuits see box 104 to 115 and box 287 Are the flow NTC sensor and safety sensor along with their wiring in correct working order gt gt box 41 step 3 Replace the flow NTC sensor safety sensor cable loom or corresponding component of the cable loom box 42 see box 116 The contacts of the flow NTC sensor and safety sensor are shorted to each other or there is a short circuit to earth ground or the flow or safety sensor has detected a CH flow temperature of above 130 C Locking boiler fault code Are the servicing valves open Open the servicing valves see box 53 Is the pressure of the heating system water at least 1 bar step 5 step 4 Fill and vent the heating system see box 52 Are enough thermostatic valves open on the radiators convectors etc step 7 step 6 Open more thermostatic valves on the radiators convectors etc box 42 Check the flow NTC sensor and safety sensor see
92. ow temperature calculated for the purposes of hot water supply Operating code Check to ensure that the CH flow temperature at the DBA control panel is higher than that entered at the controller see box 61 Is the CH flow temperature at the DBA control panel adjusted correctly Adjust the CH flow temperature at the DBA control panel to a higher setting see box 61 Check to ensure that enough thermostatic valves are open on the radiators convectors etc Are enough thermostatic valves open on the radiators convectors etc Open more thermostatic valves on the radiators convectors etc Check to see if a hot tap or taps have been opened on brief consecutive occasions Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No step 8 step 9 box 42 box 42 box 41 step 4 step 3 box 42 step 7 step 6 box 42 step 10 step 9 box 42 box 42 box 41 step 4 step 3 box 42 step 7 step 6 box 42 Buderus Ltd http www buderus domestic co uk 27 step 8 step 9 step 10 step 11 step 12 Have a hot water tap or taps been opened briefly and consectutively on several occasions Yes No Inform the user that the fault has been caused by opening hot tap
93. ox 46 Take the boiler out of operation and close the gas tap Remove the hose from the gas connection pressure see box 43 44 or 46 measurement nipple Tighten the screw on the gas connection pressure Remove the pressure gauge d measurement nipple Tighten the screw on the burner pressure measurement nipple Open the gas cock and place the boiler into full load operation see box 59 54 55 and 13 Wait for the boiler to start purpose Use a detection product to check the burner pressure Fit the casing and place the boiler into operation measurement nipple for leaks Use an authorised foam see box 51 54 or 55 type leak detection product for this purpose Open the gas tap see box 59 Use a detection product to check the gas connection pressure measurement nipple for leaks Use an authorised foam type leak detection product for this Take the boiler out of operation see box 43 or 44 Fit the casing and place the boiler into operation see box 51 54 or 55 Take the boiler out of operation and drain the heating system see box 48 to 50 DANGER OF FATAL ACCIDENT A All work on gas supply pipes and gas fitting components must be carried out by a company registered and authorised for this purpose Take the boiler out of operation and close the gas tap see box 43 44 46 or 47 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servic
94. pane 92 3 92 3 92 3 Maximum gas consumption hot water tank m h 3 02 2 43 3 02 Maximum gas consumption heating m h 2 43 2 43 2 43 Boiler efficiency 40 30 C lower value upper value full load 104 104 104 104 104 104 Boiler efficiency 40 30 C lower value partial load 107 107 107 Boiler efficiency 40 30 C upper value partial load 96 3 96 3 96 3 Boiler efficiency 75 60 C lower value upper value full load 95 7 86 2 95 7 86 2 95 7 86 2 Boiler efficiency 75 60 C lower value upper value partial load 94 6 85 2 94 6 85 2 94 6 85 2 Chimney loss with burner shut down standby heat loss at nominal 1 2 1 2 1 2 thermal load Hot water circuit AT at residual head of 200 mbar C lt 20 lt 20 lt 20 Maximum flow temperature C 80 80 80 Permitted system pressure bar 1 0 3 0 1 0 3 0 1 0 3 0 Expansion vessel Capacity of expansion vessel 7 5 7 5 7 5 Admission pressure of expansion vessel bar 1 0 1 0 1 0 Plate heat exchanger DHW flow rate at 35 C rise l min 9 4 11 7 Supply pressure of hot water bar 0 8 10 0 0 9 10 0 Adjustable DHW temperature C 40 60 40 60 Pipe connections Condensate outlet mm 21 5 21 5 21 5 CH flow return compression fitting mm 22 0 22 0 22 0 MCW inlet DHW outlet compression fitting mm 15 0 15 0 15 0 Gas on installation frame compression fitting mm 22 0 22 0 22 0 Pressure relief valve mm 15 mm adapter supplied with boiler Flue gas c
95. r Set multimeter to measure resistance Measure the resistance of the flow NTC sensor Measure the electrical resistance of the flow NTC sensor and safety sensor i a l M Measure the electrical resistance of the flow NTC sensor Set multimeter to measure resistance and check the earth ground connection of the safety sensor This must be infinitely high The measured resistance of the flow NTC sensor is virtually identical to that of the safety sensor Measure the resistance of the safety sensor We reserve the right to make technical modifications 48 Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Use a digital contact type thermometer to measure the temperature in the vicinity of the corresponding sensor Compare the resistance readings with the values listed in box 111 Replace the corresponding sensor if the reading fluctuates by more than 10 with respect to the reference value e g infinitely high resistance in the event of a line break or resistance of 0 Q in the case of a short circuit Reinsert the plug Refit the casing and place the boiler into operation see box 51 53 54 or 55 Resistance readings approximate values for the sensor Temperature Resistancein Temperature Resistancein in C Q in C Q 0
96. r warm start After service mode We reserve the right to make technical modifications Unit via g s g s C C C C ppm mg kWh ppm mg kWh Pa Vac mm kg kg mm mm 500 24 S 500 24 C 500 28 C 1 6 10 6 4 3 77 55 60 35 9 2 10 3 lt 30 lt 22 75 230 50 Hz IP X4D 4 88 110 780 x 460 x 330 780 x 460 x 330 780 x 460 x 330 30 31 31 33 34 34 IloH3p 20 mbar 37 mbar natural gas H and propane P 4 45 4 45 4 45 3 45 3 45 3 45 423 072A 423 072A 423 072A Delivered ready for operation adjusted to Wobbe index 14 1 kWh m with reference to 15 C 1013 mbar applicable to Wobbe index range 11 3 to 15 2 kWh m Markings on gas classification plate Configured category G 20 2E 20 mbar Deemed suitable for use with propane after inspection by a registered Corgi heating engineer Markings on gas classification plate Configured category 3P G 31_30 50 mbar UP 15 50 5 minutes 5 minutes 5 minutes 30 40 seconds 30 40 seconds 30 40 seconds 30 seconds 30 seconds 1 minute 1 minute 1 minute Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 7 box 6 Overview Buderus 500 z ML i a j n N We reserve the right to make techni
97. r compartment may be used provided that it is modified for the purpose In both cases details of essential features of cupboard compartment design including airing cupboard installation are to conform to the following BS 6798 No cupboard ventilation is required see Air Supply for details It is not necessary to have a purpose provided air vent in the room or internal space in which the boiler is installed Neither is it necessary to ventilate a cupboard or compartment in which the boiler is installed due to the low surface tempera tures of the boiler casing during operation therefore the requirements of BS 6798 Clause 12 and BS 5440 2 may be disregarded The permanent clearances required are in front 8mm below 21mm right side 8mm left side 8mm above 21mm The position selected for installation MUST allow adequate space for servicing in front of the boiler See table below in front 350 mm below 180 mm right side 8 mm left side 8 mm above 200 mm In addition sufficient space may be required to allow lifting access to the wall mounting bracket Wall mounted condensing gas combi boilers must only be operated with Buderus purpose made gas systems which are certified for this type of boiler Buderus Ltd http www buderus domestic co uk 4 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Observe the relevant standards regulations and legislation
98. rrent displayed Disconnect the plug and socket connection see box 144 Is the ionisation current still displayed Check the plug and socket connection between the ionisation electrode and cable loom see box 144 Is the plug and socket connection in full working order Correctly insert the plug into its socket Check the cable of the ionisation electrode see box 151 Is the wiring in order Replace the cable loom or the affected part thereof Check the ionisation electrode see box 149 or box 155 Is the ionisation electrode working correctly Replace the ionisation electrode see box 155 Switch the boiler off and then on again at the operating switch The following components should be checked for soiling damage and or correct installation syphon see box 256 flue gas pipework Check the pressure control valve see box 85 Is the pressure control valve working correctly Replace or clean the pressure control valve see box 85 An ionisation current has been measured as soon as the burner shuts down E Locking boiler fault code om rt IWIN Connect a digital pressure gauge see box 233 and 234 Open the gas cock and place the boiler into full load operation see box 59 or box 13 Deactivate the heat requirement as per flue gas test box 13 and check to see if the burner remains under pressure after the heat requirement symbol on the DBA control panel goes out Is the burner still
99. rus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 11 C box 12 Normal Operation menu 2H Current CH flow temperature in C See also box 20 Keep the V button pressed O0 current DHW flow rate in litres per minute Continue with Normal Operation menu Release the V button Keep the A button pressed OH Operating code See also box 20 In this case The boiler is ready for operation No current heat requirement box 13 Service Mode menu no hot water is available during service mode operation 24 Current CH flow temperature in C See also box 20 Activate service mode step 3 step 1 Press the button once 24 As soon as the spanner symbol on the left hand side of the display and the flame appear the boiler will run for 30 minutes in service mode The maximum CH flow temperature as configured in the Settings menu applies in this case Briefly press the A button Partial load service mode L a is activated Check the gas air ratio and ionisation current Adjust the gas air ratio as required See box 233 and box 143 Exit partial load service mode Press the button once Briefly press the A button Full load service mode H _ is activat
100. s on many brief consecutive occasions Check the electrical resistance of the DHW temperature sensor see box 104 Is the electrical resistance of the DHW temperature sensor in order Yes No Replace the DHW temperature sensor EiS 105 C TANTIN Locking boiler fault code DAN Short circuit between flow NTC sensor or safety sensor L Locking boiler fault code TANVIN step 1 Are the servicing valves open Yes No step2 Open the servicing valves see box 53 step 3 Is the pressure in the heating system at least 1 bar Yes No step 4 Fill and vent the heating system see box 52 step 5 Are enough thermostatic valves open on the radiators convectors etc Yes No step 6 Open more thermostatic valves on the radiators convectors etc step 7 Check the flow NTC sensor and safety sensor see box 104 step 8 Are the flow NTC sensor and safety sensor in order Yes No step 9 Replace the flow NTC sensor or safety sensor see box 116 step 10 Check the cable between the flow NTC sensor or safety sensor for short circuits see box 112 step 11 Check the pump see box 89 to 100 step 12 Is the pump working correctly Yes No step 13 Replace the pump see box 101 step 14 Check to ensure that the internal by pass valve in the boiler or the external overflow valve in the heating system are working correctly Possible to adjust external overflow valve to max 25 kPa if fitte
101. s or ON OFF controller has been adjusted to a high enough setting see operating instructions step3 Is the preset room temperature or heating configuration of the Buderus controls or ON OFF controller adjusted to a high enough setting step 4 Adjust the preset room temperature controller or heating configuration of the Buderus controls or ON OFF controller to a higher setting see operating instructions step5 Check to see if the heating requirement TO indicator lights up on the display see box 11 step6 Does the heating requirement am indicator light up step7 Check the Buderus controls or ON OFF controller as per box 177 step8 Is the Buderus controls or ON OFF controller working correctly step9 Replace the thermostat cable step 10 Replace the Buderus controls or ON OFF controller step 11 Check to ensure that the CH flow temperature at the DBA control panel or on the Buderus controls or ON OFF controller is adjusted to a high enough setting as per box 14 and box 61 step 12 Is the CH flow temperature adjusted to a high enough setting step 13 Are enough thermostatic valves open on the radiators convectors etc step 14 Open more thermostatic valves on the radiators convectors etc step 15 Adjust the CH flow temperature as per box 14 and box 61 Ensure that the Buderus controls or ON OFF controller are calling for a heating demand step 16 Check to ensure that the CH flow temper
102. tch optimisation program is activated This program is activated if there is Ti more frequently than once every 10 minutes a heating water requirement from an Li H Buderus controller or ON OFF controller signal This means that the boiler cannot be restarted until at least 10 minutes have elapsed since initial startup of the burner Operating code Check to ensure that the connections of the control device are correctly fitted at the boiler and control device Is the control device connected correctly Connect the control device correctly Carry out a visual examination where possible and use a multimeter to check the electrical resistance of the thermostat lead Check for breakages and loose contacts Is the thermostat cable in good condition Replace the thermostat cable Check to ensure that enough thermostatic valves are open on the radiators convectors etc Are enough thermostatic valves open on the radiators convectors etc Open more thermostatic valves on the radiators convectors etc Attempt to rectify the fault by temporarily replacing the room thermostat or external temperature dependent controller Has the malfunction been repaired The flow NTC sensor has detected that the current CH flow temperature is higher Ti than the temperature entered at the control unit or that it is higher than the CH flow Lu Y temperature calculated according to heating requirements or that it is higher than the CH fl
103. ter to measure resistance Check the cables of the flue gas STL for breaks The electrical resistance measured at each individual wire must be approximately 0 Q Check the cables of the flue gas STL for internal short circuits The level of electrical resistance measured between two wires chosen at random must be infinitely high insert both plugs at the flue gas STL fit the DBA control panel attach the casing and place the boiler into operation see box 51 54 or 55 Take the boiler out of operation see box 43 44 or 47 Remove both plugs of the flue gas STL see box 121 Twist the flue gas STL anticlockwise to remove Fit the new flue gas STL Use a new seal when doing so Insert both plugs at the flue gas STL and place the boiler into operation see box 51 54 or 55 Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 51 box 130 Check the glow ignitor activation DANGER OF FATAL ACCIDENT due to electric shock Take the boiler out of operation see box 43 44 or 47 Q Eo AS Pull out the plug of the glow ignitor item 1 box 132 1 Set the multimeter to measure AC voltage Minimum measuring range 230V AC Put the boiler into partial load or full load operation see box 13 Check to see whether with the operating code OC
104. th the operating code OL see box 164 Does the gas valve receive power Replace the gas valve see box 174 Check the power supply cable of the gas valve see box 167 Is the wiring in order Replace the cable loom or the affected part thereof Check whether the incoming gas supply is of sufficient capacity Is the incoming gas supply of sufficient capacity Upgrade internal pipe work Consult your gas utility company accordingly Measure the gas air ratio during the startup phase see box 233 Is the gas air ratio correctly adjusted Adjust the gas air ratio see box 233 Check to ensure that the correct gas injector see box 83 item 1 and the correct Venturi see box 87 item 1 are fitted as specified See also box 5 Is the correct gas injector and Venturi fitted Fit the correct gas injector and or Venturi see box 5 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No box 41 step 20 step 62 step 24 step 23 step 62 step 26 step 23 step 41 step 28 step 31 step 30 step 62 step 33 step 34 step 62 box 41 gt step 36 step 62 step 40 step 39 step 62 step 62 step 44 step 43 step 62 st
105. the DBA and test for continuity between Te gt box 43 leads No continuity check S L and N connections are made correctly and that there is 230v between the two Replace RTH converter Junction box Continuity reconnect the cables to terminals 1 amp 2 and check the connections between the terminals and the DBA drve the right to make technical modifications Buderus Ltd http www bud rus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C ssued 02 2005 Operating step number Explanation of this subject starts in this box The following boxes can be relevant as well We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 10 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Operation eh box 10 Operation General points PPO ry 1 Pee rrr Peer p nnns The central boiler can be run from the DBA control panel item 1 item 1 Mains switch 0 1 item 2 Reset button item 3 Service button item 4 Display item 5 Menu button item 6 Adjusting arrow UP item 7 Adjusting arrow DOWN You can navigate through the menu structure of the central boiler using the service button reset button button and button item 2 3 5 6 and 7 and the display item 4 box 12 to 14 We reserve the right to make technical modifications Bude
106. the arrow to remove drawing 2 Check to see if the fan is soiled or wet Check to see if the fan impeller has come loose at the motor spindle Loosen the three screws item 1 on the gas valve Remove the gas valve item 2 We reserve the right to make technical modifications ae 62 Remove the Venturi item 1 Fit the Venturi to the new fan Co Fit the gas valve to the new fan When doing so ensure that the gas injector item 1 is correctly fitted Fit the fan to the boiler Remember to fit the new flat rubber sealing ring supplied when doing so Fit the air silencer tube to the fan Fit the gas supply pipe to the gas valve Ensure when doing so that the flat rubber sealing ring is correctly fitted Insert the power supply plug into the gas valve then insert the power supply plug and tacho cable plug into the fan Open the gas cock and place the electrical system of the boiler into operation see box 59 54 or 55 Carry out a gas leak check Check the tightness of all components that were loosened in the course of component removal Use an authorised foam type leak detection product for this purpose If you detect a gas leak refer to box 46 43 or 44 Remedy the cause of the gas leak Open the gas cock place the electrical system of the boiler into operation and fit the cas
107. the internal 3 way valve e Take the boiler out of operation and drain the heating w BA system see box 48 to 51 A F a ae box 204 2 Pull the plug item 1 out of the pump Loosen the four screws item 3 on the pump Remove the return pipe with spring item 4 Remove the pipe to the expansion vessel with spring item 5 Pull out the pump item 2 Disconnect the cable from the main switch see box 54 Pull the spring off the flow NTC sensor lead item 1 Pull out the flow NTC sensor plug item 2 Pull the main switch cable out of the nut item 3 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 61 Remove all pipes beneath the boiler CAUTION LS Note that water will squirt out when the internal 3 way valve is removed Have a bucket and a supply of dry cloths to hand Loosen the gas pipe at the gas valve Remove the two screws item 1 Remove the complete hydraulic assembly Remove the four M8 nuts item 2 Remove the five screws item 3 Remove the plastic block H3 Ah d Loosen the screw in the plastic block item 2 Remove the pressure relief valve item 1 see box 276 or 277 Remove the drive mechanism on th
108. the wiring of the Buderus 24V AC external 3 way valve see box 220 Is the wiring of the Buderus 24V AC external 3 way valve in correct condition Yes No Replace the wiring of the Buderus 24V AC external 3 way valve Check the drive mechanism of the Buderus 24V AC external 3 way valve see box 221 Is the drive mechanism of the Buderus 24V AC external 3 way valve working correctly Yes No Replace the internal components of the Buderus 24V AC external 3 way valve see box 224 Check the wiring of the Buderus 24V AC external 3 way valve between the connection box or moving plug and socket connection and the DBA control panel as per box 287 On combi boiler supply hot water available but no heating operation On system boiler supply no heating operation Hot water may be available but no heating operation step 1 step 2 step 3 step 4 step 5 step 6 We reserve the right to make technical modifications 26 Check to ensure that the power supply cable to the RTH converter Junction box has been installed correctly see box 285 Is the 230V connection to the RTH converter Junction box fitted correctly Yes No Correctly attach the switch live to terminal 1 and Neutral to terminal 2 on the 230V connector see box 285 Disconnect black leads from terminals 1 amp 2 on the back of the DBA and test for continuity between the two leads No continuity check S L and N connections are made correctly and that there is 23
109. to appear This prevents sudden pressure surges occurring in the heating circuit while the removal operation is taking place and the resultant accidental opening of the pressure relief valve Fit the new servomotor by following the above procedure in reverse order Put the boiler into operation see box 51 54 or 55 Buderus Ltd http www buderus domestic co uk Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 63 N CAUTION N To prevent damage do not insert the measuring electrodes of the multimeter too far into the holes of the plug and socket connection Take the boiler out of operation see box 43 or 44 Remove the power supply plug of the servomotor of the Buderus 24V AC external 3 way valve see box 213 Remove the connection of the power supply cable of the Buderus 24V AC external 3 way valve at the boiler Set multimeter to measure resistance Check the power supply cable of the Buderus 24V AC external 3 way valve for breaks The electrical resistance measured at each individual wire must be approximately 0 Q Check the power supply cable of the Buderus 24V AC external 3 way valve for internal short circuits The level of electrical resistance measured between two wires chosen at random must be infinitely high Insert the power supply plug of the Buderus 24V AC external 3 way valve Connect the power supply cable of the
110. trictor baffle been fitted Yes gt step 4 No step 3 Fit the restrictor baffle see box 261 item 1 box 42 Check the entire system of flue gas pipe for restrictions Is the entire system of flue gas pipe in full working order Yes step7 No step 6 Deal with restriction box 42 Check the flue gas STL see box 120 Is the flue gas STL working correctly Yes step 10 No step 9 Replace the flue gas STL see box 129 Check the wiring of the flue gas STL see box 126 Is the wiring of the flue gas STL in full working order Yes box 41 No step 12 Replace the cable loom or the affected part thereof The tacho signal from the fan has failed during the operating phase Blocking boiler fault code The tacho signal from the fan is not present during the pre operative or operating phase Locking boiler fault code Check to ensure that both plug and socket connections of the fan are correctly fitted see box 246 item 1 Are the plug and socket connections fitted correctly Yes step4 No step 3 Reconnect the plug and socket connection of the fan box 42 Check fan 230V AC supply see box 66 or box 287 Does activation take place correctly Yes step9 No step 6 Check the power supply cable of the fan 230V AC see box 69 Is the power supply cable of the fan in ful
111. under pressure Check the ionisation electrode see box 37 Close the gas cock see box 46 Remove the digital pressure gauge and close the burner pressure connection nipple Open the gas cock see box 59 and run the boiler at full load once more see box 59 or box 13 Deactivate heat requirement see box 13 and check to see if the gas valve is still powered after the heat requirement indicator goes out see box 165 item 1 and 2 Is the gas valve still powered Replace the gas valve see box 174 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No step 2 step 1 step 12 box 41 step 7 step 6 step 11 step 10 step 9 step 13 box 42 step 14 step 12 box 42 box 41 step 17 box 42 step 4 step 3 box 41 step 6 Buderus Ltd http www buderus domestic co uk 35 re Peares The power supply was shut off during operation Locking boiler fault code Reset the boiler with button or by turning the operating switch to OFF and then ON again Is the error code still displayed gt step3 box 42 Interpret the fault code now displayed in box 20 and deal with the malfunction The contacts of the gas valve have been broken
112. usted to 5 minutes via the external reservoir set to 30 40 seconds via the plate heat exchanger ECO set to 30 40 seconds via the plate heat exchanger warm start set to 30 seconds after service mode 1 minute step13 Has the pump over run time expired Yes step 18 No step 14 step14 Is the boiler set to warm start for hot water and or is an external storage type water heater connected Yes step15 No step 16 step15 Is the plate heat exchanger triggered and or is the temperature in the external storage type water heater atleast Yes step 28 5 C below the temperature set at the DBA control panel No gt step 16 step16 Is there a current heat requirement from the room temperature controller Yes step 46 No step 19 step17 Is the current CH flow temperature lower than 7 C frost protection Yes step 62 No step 18 step18 The pump stops step19 Has the pump been out of use for more than 24 hours Yes step 23 No step 20 step20 Is the plate heat exchanger triggered and or is the temperature in the external storage type water heater atleast Yes step 28 5 C below the temperature set at the DBA control panel No gt step 21 step21 Is there a current heat requirement from the room temperature controller Yes step 46 No step 22 We reserve the right to make technical modifications Buderus Ltd http www buderus domestic co uk 14 Servi
113. ve the rear section see box 70 Remove the plug of the ionisation electrode see box 144 0e 00000000000000 U lu a ZE S JP4 S Set the multimeter to measure resistance Take a reading at the ionisation electrode to check whether there is a possible break in the cable of the electrode The electrical resistance of the cable must be approximately 0 Q r IER Sn li N Take an earth ground reading check whether there is a possible short circuit between the cable of the ionisation electrode and earth ground The electrical resistance between the ionisation electrode cable and earth ground must be infinitely high Buderus Ltd http www buderus domestic co uk 54 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 box 154 Connect the plug of the ionisation electrode Refit the DBA control panel by following the above procedure in reverse order and place the boiler into operation see box 51 54 or 55 box 155 Check and replace the ionisation electrode Take the boiler out of operation see box 43 44 or 47 Remove the plug of the ionisation electrode see box 144 box 156 Loosen the fixing nut on the ionisation electrode item 1 Remove the mounting plate item 2 Detach the ionisation electrode item 3 box 157
114. vomotor of the 3 way valve see box 182 WI L O ar SE Ne By ZL Y Z X Check to ensure that the drive mechanism of the 3 way valve is running smoothly This is done by gradually pushing the spring fully home by hand and allowing the spring to return gradually to its home position Refit the servomotor following the above procedure in reverse order Put the boiler into operation see box 51 54 or 55 We reserve the right to make technical modifications Take the boiler out of operation and drain the heating system see box 48 to 51 Remove the servomotor of the 3 way valve see box 182 Remove the stop spring item 1 by pulling it in the direction of the arrow Remove the drive mechanism item 1 of the 3 way valve CAUTION Note that water will squirt out when the drive mechanism is removed Have a bucket and a supply of dry cloths to hand Buderus Ltd http www buderus domestic co uk 60 Servicing manual Gas condensing boiler Buderus 500 24 S 500 24 C and 500 28 C Issued 02 2006 box 201 box 205 Fit the new drive mechanism on the internal 3 way valve Ensure that the flat side faces upwards box 202 Connect the servomotor of the 3 way valve by following the above procedure in reverse order Fill the heating system vent it of air and place the boiler into operation see box 52 to 58 Q box 203 Replace
115. way valve see box 218 box 43 step 42 Check the wiring of the Buderus 24V AC external three way valve see box 221 step 43 Is the wiring of the Buderus 24V AC external three way valve in correct condition Yes gt step 47 No gt step 44 step 44 Replace the wiring of the Buderus 24V AC external three way valve box 43 step 45 Check the drive mechanism of the Buderus 24V AC external three way valve see box 222 step 46 Is the drive mechanism of the Buderus 24V AC external three way valve working correctly Yes gt box 42 No gt step 47 step 47 Replace the internal components of the Buderus 24V AC external three way valve see box 225 box 43 step 48 Check the wiring of the Buderus 24V AC external three way valve between the connection box or moving plug and socket connection and the control panel as per box 288 On combi boiler supply hot water available but no heating operation On system boiler supply no heating operation Hot water may be available but no heating operation step1 Check to ensure that the power supply cable to the RTH converter Junction box has been installed correctly see box 286 step 2 Is the 230V connection to the RTH converter Junction box fitted correctly Yes gt step 4 No gt step3 Correctly attach the switch live to terminal 1 and Neutral to terminal 2 on the 230V connector se box 2 Disconnect black leads from terminals 1 amp 2 on the back of

SA - Buderus 500-24S/24C/28C

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