Suburban Service Manual
Contents
1. 22 Sequence of Operation Time Delay Relay Equipped Furnaces 23 Sequence of Operation Fan Control Module Board 520820 Equipped Furnaces 24 Sequence of Operation 24 VAC Fan Control Module Board 520947 25 Sequence of Operation SHD 2542 Furance 26 Trouble Shooting Flow Chart Furnaces Equipped with Time Delay Relay 27 Trouble Shooting Flow Chart Furnaces Equipped with Fan Control Module Board 28 Service Hints Diagnosis and Corrective Measures for Suburban 24 Volt AC Electronic Ignition Furnaces 29 30 Wiring Diagrams s s ise oe Pade Oe lea Mea tite u es AAU m 30 34 Furnace Removal REIR we a ay AE CREE Rie E 35 36 SF SH SHD 2542 Electrode Gap Specifications amp Positioning 37 NT and Park Model Electrode Gap Specifications amp Positioning 38 sue uu Z bsp 39 Cautions 4 Safety Information Back Cover NOTE Our service technicians are available to assist you in making repairs or parts replacements from 8 00 a m to 5 00 p m Eastern Standard Time Monday through Friday except holidays by calling 423 775 21312. TIE OOWN SCREW FURNACE TO CABINET OUTSIDE SION BACK OF CABINET MUST BUTT AGAINST THIS EDGE OF FRAME DOOR FRAME SECURE FRAME TO OUTER PANEL WITH SCREWS 16 PLACES SEE NOTCH DETAIL FURNACE ACCESS DOOR 4 SCREWS DOOR MOUNTING CAULK BEHINO VENT CAP AS SHOWN TO SEAL BETWEEN EXHAUST TO FLOOR USING AND INTAKE AND TO PREVENT MOISTURE INSIDE FURNACE COMPARTMENT APPLY CAULKING GENEROUSLY AROUND PERIMETER 2 810 X OF VENT AND ACROSS CENTER AS SHOWN CENTER PUTTY STRIP SCRENS PRONE 4 4 C 13 ESSENTIAL NOTCH DETAIL FLOOR AND OUTER SKIN MUST BE NOTCHED AS SHOWN BELOW CAULK ALONG THE EDGE OF THE CUTOUT ALL THE WAY AROUND AIR INTAKE TUBE WITH GASKET VENT amp EXHAUST TUBE ANCHOR BRACKET N TO FLOOR USING 2 10 X 34 SCREWS PROVIDED CABINET SUPPORT BRACKET WELDED TO CABINET Figure 5 MOUNTING USE IF POSSIBLE gt NEVER INSTALL THE EXHAUST TUBE WITH LESS THAN 1 1 4 OVERLAP OR THE INTAKE TUBE TRAILER SKIN WITH LESS THAN 1 2 OVERLAP el T KX bag amp INTAKE o o 77 74 GASKET BOTTOM DUCT MOUNTING SURFACE BRACKET CABINET MOUNTING X DIMENSION EXTENSION TUBES KIT NO ONE PER SIDE 520767 112 3 K USE SUPPLIED wm FURNACE 3 TO 4 1 2 520768 41 2 TO 7 1 2 STANDARD VENT ASSEMBLY FURNISHED WITH FURNACE SPECIAL EXTENSION TUBES IF NEEDED MUST
3. a Check for proper voltage at module board after the blower motor reaches full r p m If no voltage check continuity through micro switch and limit switch Also check wiring and wire connections Voltage is present but no spark at electrode after 12 18 second delay check electrode wire connections Wire connections OK but electrode wire does not show continuity through it replace electrode wire Electrode wire does show continuity through it check electrode gap to be sure it is 1 8 maximum between electrode and ground NOTE Gap between sensor and ground must be twice electrode gap Electrode gap OK check electrode assembly for possible cracks or carbon on tip of electrode f Electrode OK replace module board Electrode sparking but gas not coming through burner a Check to see if voltage is coming out of module board to gas valve after the 12 18 second delay Check the wires in the molex connector to be sure they are intact and making contact with the module board Check wire from the module board to valve for continuity Wire and connections check OK replace module board Voltage is coming out of module board to gas valve but gas valve does not open replace gas valve Electrode sparking and gas valve opening but burner will not light a Check to see if gas is coming through to the burner This can be accomplished by using a flow meter in the gas supply line If no gas is coming through the burner
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5. No gt NOTE On some models sail switch is before limit switch TROUBLE SHOOTING GUIDE SUBURBAN RV FURNACE with FAN CONTROL MODULE BOARDS Thermostat Closes No gt Yes No gt Blower is operating at call for heat v Motor is operating No gt Yes After 15 seconds the module gt creates spark and opens valve No Yes Spark occurs for approximately 7 seconds and main burner flame establishes No gt Yes Thermostat opens and the module board No gt operates the fan for the cool down cycle Yes System 12 VDC HEATING SECTION Check thermostat wire connections contact points and the heat anticipator Yes gt No Check 1206 at blue wire check the amp draw to thermostat No v Check for shorts Check components amperage Yes Check for 12vdc at furnace Yes Y Check fuse or circuit breaker Yes Y Yes gt Yes gt No gt No gt Check for 12vdc at power terminal on No gt module board and for 12vdc to red wire leading to the motor Yes v Check ground wire on terminal block Reset thermostat Motor operating Check for 12 vdc at blue wire on molex edge connector No gt Yes gt Check for 12vdc between red and yellow wires at the module board Yes gt Check for 12vdc at limit switch both sides Yes gt No Check for 12406 at sail
6. check for obstruction in gas line in main burner orifice or in main burner Gas is coming through burner but spark will still not ignite burner check gas pressure Line Pressure Min 11 W C Max 14 W C To properly check pressure first determine the line pressure cycle furnace and check pressure drop on demand The drop in pressure should not be more than 72 W C A drop of more than 1 2 would indicate a faulty regulator a restriction in the gas line or a pinched gas line Excessive pressure drop could also be due to moisture contamination c Gas pressure OK check for obstruction in main burner check to be sure electrode is positioned approximately 1 4 above and directly over slots on the main burner adjust electrode if necessary e b d 4 Be sure the electrode assembly screws are snug at all times especially after the electrode has been removed and reinstalled 5 If the module board is found to be defective it must be replaced it is not field repairable Any attempts to repair the board may alter the board and cause it to operate in an unsatisfactory manner 6 Insure that the gap between electrode and ground is always 1 8 The gap between the flame sensor should be approximately twice the gap between electrode and ground to insure no sparking to sensor Sparking to sensor will damage the module board 3 The module board also performs the lockout function in cases where the spark fails to l
7. D X 5 STANDARD NEVER INSTALL VENT TUBES STANDARD TUBE FURNISHED WITH FURNACE WITH LESS THAN 1 2 OVERLAP THE SPECIAL TUBES IF NEEDED MUST ON INTAKE amp 1 1 4 ON EXHAUST BE ORDERED Figure 8 NT 12 16 20SE IMPORTANT VENT CAP AND TUBE ASSY MUST BE INSTALLED FROM OUTSIDE OF COACH TRAILER SKIN HOLE DIA IN OUTER SKIN MAY BE 2 1 4 OUTLINE OF FURNACE IN COMI A CLE SLED INFINE a CAULK BEHIND VENT CAP AS SHOWN TO SEAL OR 4 HOLE DIA MUST BE 2 3 4 IF THE BETWEEN EXHAUST AND INTAKE AND TO PREVENT 4X7 1 2 OPENING AS SHOWN IN FIGURE MOISTURE INSIDE FURNACE COMPARTMENT 41S NOT CUT THROUGH COMBUSTIBLE APPLY CAULKING GENEROUSLY AROUND WALL 4 PERIMETER OF VENT AND ACROSS CENTER 2 AS SHOWN CENTER PUTTY STRIP IS ESSENTIAL VENT CAP amp EXHAUST TUBE ASSEMBLY INTAKE TUBE INSTALLING VENT CAP Figure 9 NT 12 16 20S and SE VENT TUBE INSTALLATION NT 16S LN TRAILOR SKIN VENT TUBE EXHAUST 8 X 2 OD VEN CAD VENT TUBE ASSY INTAKE SEE CHART P 11 4 MIN OVERLAP 1 2 MIN OVERLAP INTAKE TUBE LENGTH ONLY 2 O D X 5 SPECIAL 2 O D X 7 1 4 SPECIAL NEVER INSTALL THE EXHAUST TUBE WITH LESS STANDARD TUBE FURNISHED WITH FURNACE THE THAN 1 1 4 OVERLAP OR THE INTAKE TUBE WITH SPECIAL TUBES IF NEEDED ARE TO BE ORDERED LESS THAN 1 2 OVERLAP Figure 10 NT 12 16S 12 VENT ASSEMBLY INSTALLATION NT SERIES VENT TUBE INSTALLATION NT 20S x TR
8. Models except SF Vent Assemblies are included with all units except DD INSTALLATION There are several important aspects of the installation which will pertain to all Suburban forced draft furnaces regardless of the model or the method in which they are installed They are 1 Selecting a Location 2 Venting 3 Return Air 4 Ducting Refer to the furnace installation manual for all installation requirements Location and Installation Locate the furnace near lengthwise center of the coach Choose a location for installation out of the way of wires pipes etc which might interfere with the installation Adhere to the minimum clearances from cabinet to combustible construction as listed in the installation manual for your specific furnace model Secure furnace cabinet to the floor of the coach using the holes provided in the furnace cabinet RETURN AIR OPENING IN R ETURN AIR OPENING IN LIVING AREA DF Z TRAILER P Figure 1 VENTING Venting By definition of a Direct Vent Sealed Combustion Furnace it must be vented to the outside atmosphere and also draw combustion air from outdoors Therefore it is imperative that the vent be unobstructed and there must be a seal between the exhaust and intake caulking Refer to the vent assembly installation in the manual The vent must be straight There can be no offsets or turns in the vent All vent tubes which connect to the furnace exhaust and intake must overlap a minimu
9. THE CHAMBER AS SHOWN BY ARROWS TO REMOVE SOOT OR LOUSE DEBRIS Figure 34 TO CLEAN THE CHAMBER THE FURNACE MUST BE REMOVED FROM THE CABINET AND ALL PARTS REMOVED LEAVING THE CHAMBER ONLY AS SHOWN USING COMPRESSED AIR BLOW THROUGH OPENINGS AS SHOWN BY ARROWS Figure 36 TO CLEAN THE CHAMBER THE FURNACE MUST BE REMOVED FROM THE CABINET AND THE MANIFOLD BLOWER ASSEMBLY AND CONTROLS REMOVED LEAVING THE CHAMBER ONLY AS SHOWN USING COMPRESSED AIR BLOW THROUGH THE CHAMBER AS SHOWN BY ARROWS TO REMOVE SOOT OR LOOSE DEBRIS Figure 35 TO CLEAN THE CHAMBER THE FURNACE MUST BE REMOVED FROM THE CABINET AND THE MANIFOLD BLOWER ASSEMBLY AND CONTROLS REMOVED LEAVING THE CHAMBER ONLY AS SHOWN USING COMPRESSED AIR BLOW THROUGH THE CHAMBER AS SHOWN BY ARROWS TO REMOVE SOOT OR LOOSE DEBRIS Figure 37 gt o 10 11 12 13 CAUTIONS amp SAFETY INFORMATION Never use a battery charger to power or test an electronic ignition furnace as they sometimes provide more than 14 5 DC Volts that could damage the module board Never operate the furnace with the electrode wire disconnected nor with the electrode assembly removed from the furnace Never use a screwdriver on any part of the electrode assembly while the furnace is in operation Be certain that the spark from the electrode never reaches the flame sensor portion of the electrode assembly on remote sense units Install the furnace so electr
10. TO SEAL BETWEEN EXHAUST AND INTAKE AND TO PREVENT MOISTURE INSIDE FURNACE COMPARTMENT APPLY CAULKING GENEROUSLY AROUND PERIMETER OF VENT CAP AND ACROSS CENTER AS SHOWN CENTER PUTTY STRIP IS ESSENTIAL CINTAKETUBE 7 ANCHOR VENT ASSEMBLY WITH THE SCREW PROVIDED BE SURE SCREW ENGAGES FURNACE EXHAUST TUBE AND IS PULLED SECURE 2 3 4 DIA TWO HOLES Figure 13 NT 24 30 34SP P 30 EXTENSION TUBE MIN MAX LENGTH KIT NUMBER Extension Tube Range 520498 2 1 4 to 3 1 8 _____ 1 4 to 3 1 8 520499 ee 1 8 to 4 7 8 520500 4817 to 7 520501 Figure 14 NT 24 30 34SP P 30S EXTENSION TUBE MIN MAX LENGTH KIT NUMBER Extension Tube Range 520594 3 1 8 to 4 7 8 Figure 15 NT 40 P 40 VENT ASSEMBLY INSTALLATION NT 40 and P 40 HEAT SHIELD COLLAR 3 50 FROM CENTER LINE OF INTAKE TO EXHAUST CENTER LINE OF EXHAUST 7 50 FROM CENTER LINE OF INTAKE TO FLOOR 2 3 00 DIA HOLES INSIDE WALL OUTSIDE SKIN AIR INTAKE FURNACE POWER SUPPLY WIRES MAXIMUM WALL THICKNESS 2 25 NOTE 0 CLEARANCE PERMISSIBLE AT REAR OF FURNACE FOR A WIDTH OF 2 25 MAXIMUM GAS FITTING ANCHOR TO FLOOR Figure 16 NT 40 VENT CAP 8 50 FROM CENTER LINE OF INTAKE TO EXHAUST CENTER LINE OF EXHAUST 7 50 FROM CENTER LINE OF INTAKE TO FLOOR 2 3 00 DIA HOLES INSIDE WALL OUTSIDE SKIN FURNACE POWER SUPPLY VIRES MAXIMUM WALL THICKNESS 2 25 THERMOSTAT WIRES NOTE 0 CLEARANCE PERM
11. burner 3 16 from back of lance and parallel with lance Make an additional mark indication center line of the lance See illustration Both marks will be used later as reference marks therefore keep lines thin Reassemble the burner into the chamber Be sure the air baffles plates are positioned as removed Mount center clip in place Adjust electrode so the electrode probe is positioned along the marked center line of the burner lance and the tip of the electrode terminates 3 16 from the back of the lance at the line marked in Step 3C See illustration IMPORTANT Be sure electrode probe maintains a 1 8 spark gap over the burner as illustrated Reinstall burner access door and reconnect manifold Manifold must be checked for leaks with unit operating before installing in cabinet Reinstall furnace into the cabinet following the instructions in the installation manual Check all gas connections for leaks using proper leak test solution ELECTRODE X MARKED CENTERLINE DF LANCE 92292929 0002000 TOP DF BURNER FRONT END OF BURNER FLASHLIGHT ieee BURNER 308 FROM BACK OF LANCE 125 SPARK GAP OVER TOP OF BURNER VENTURI TUBE Figure 31 37 NT ELECTRODE GAP SPECIFICATIONS AND POSITIONING To assure consistent ignition of the burner it is important for the electrode to be positioned properly over the top of the burner When replacing the electrode or should you be experiencing ig
12. for the minimum return air area for your specific furnace model Insufficient return air will cause the furnace to overheat and cycle on limit Another symptom of a return air problem is 1 Furnace seems to run continuously in an effort to satisfy the thermostat OPENING FOR RETURN AIR SPACER BUMPS lt s RETURN AIR 24 TD SPACER FURNACE MAINTAIN 1 4 INCH CLEARANCE WHERE DUCTS PASS THROUGH CABINET WALL UL LISTED DUCT 0 TO SPACER MATERIALS CAN BE 0 CLEARANCE THE TOTAL FREE UNOBSTRUCTED RETURN AIR OPENING TO THE FURNACE MUST NOT LESS THAN THE MINIMUM Figure 19 16 DUCTING Ducting Suburban furnaces require that a minimum duct area be maintained throughout entire duct system including through the register It is very important to adhere to the minimum duct area in order to keep the furnace from cycling on high limit and to assure proper operation of the sail switch sometimes referred to as a microswitch NOTE Refer to the installation manual for the minimum ducted square inches area for each model NOTE Ducts terminating in a dead air space like holding tank compartments or cargo areas Toy Boxes with no means for return air recirculation should not be counted in the required duct area Also ducts 2 in diameter or smaller should not be counted in the required duct area When installing a duct system avoid making a lot of turns The straighter the duct system the less the resistance to ai
13. seconds a second 15 second purge cycle will begin followed by a second Trial For Ignition sequence After three 3 Trial For Ignition attempts with no ignition of the main burner the module board will de energize the gas valve immediately and blower will run for 90 seconds and then shutdown in lockout If during the heating cycle the limit switch circuit opens and remains open the gas valve will close and the blower motor will continue to run When the thermostat has reached its set point and the demand for heat ends the gas valve will be de energized and the flame will go out The post purge period of 90 seconds begins When it times out the blower motor output is removed and the blower stops 25 Sequence of Operations for SHD 2542 1st Stage Call for Heat The wall thermostat controls the operation of the dual stage furnace by reacting to room temperature This allows current to flow through the On Off switch to the Blower Speed Control Board then to the Module Board The module board constantly checks for a minimum 9 5 volts If there is not 9 5 volts the module board will go into a standby mode until adequate power is supplied It will then resume normal operation Upon a call from the thermostatthe first stage will be activated The module board thermostat circuit will go active and the sail switch is verified as being open The blower output is energized The blower motor starts 15 Second Purge Cycle The module board will
14. switch both sides Yes gt No gt No spark at the electrode Yes Check for 12vdc at gas solenoid valve Yes Did the gas valve open Yes Check for restriction in combustion air Intake wasps etc No Y Is flame established Replace the module board No gt No gt 28 Clean points secure loose connections replace thermostat if anticipator is shorted Replace thermostat Repair or replace connections or parts with higher than normal amp draw Check on off switch on furnace Replace fuse Reset breaker Replace the module board after confirming motor operation Replace the motor Verify voltage thru limit and sail switch to module board If circuit remains open for 30 seconds module board will go into lockout and shut down motor Reset thermostat Replace defective part Check plug connection to the module electrode and wire spark gap 1 8 inch between probe and ground Replace the sail switch Replace the limit switch Replace the module Replace the module Check gas pressure at the manifold or for restrictions in the burner orifice No Replace the gas valve Check flame contact to electrode Flame should be hard blue SERVICE HINTS DIAGNOSIS AND CORRECTIVE MEASURES FOR THE IGNITION SYSTEMS OF SUBURBAN 24 VOLT ELECTRONIC IGNITION GAS FURNACES WITH TIME DELAY CAUTIONS 1 Never operate the furnace wi
15. then verify that the sail switch circuit is closed and motor is up to speed If this circuit remains open for 30 seconds after the blower motor starts the module board will go into lockout and shut down the blower motor The module board checks that the gas valve relay contacts located on the module board are open before the igniting sequence starts The board has a pre purge timing circuit of approximately 15 seconds This allows the combustion chamber to purge 7 Second Ignition Cycle and Flame Sense The module board will energize the gas valve and enable the high voltage spark output to the electrode for a seven second ignition period The module board will then check for flame sense to verify successful lighting of the main burner flame Sparking of the igniter is then terminated The gas valve and blower outputs will remain energized If ignition is successful the module board will monitor the flame sense sail switch and the limit switch circuits The flame is sensed through the spark wire and electrode therefore it is essential that the electrode is properly positioned in the burner flame 3 try Ignition Board If the flame is NOT sensed after seven 7 seconds or if the unit fails to ignite a second fifteen 15 purge cycle will begin followed by second trial for ignition sequence After three 3 trial for ignition attempts with no ignition of the main burner the module board will de energize the gas valve immediately and the blo
16. tie down screw securing the chamber to the cabinet Remove the furnace from the cabinet by pulling chamber outward completely to gain access to all controls and applicable parts To re install reverse this procedure Rewire applicable wires and perform a leak test on all fittings Perform a drop pressure test 36 SF SH AND SHD 2542 ELECTRODE GAP SPECIFICATIONS AND POSITIONING To assure consistent ignition of the burner it is important for the electrode to be positioned properly over the top of the burner When replacing the electrode or should you be experiencing ignition type problems the electrode should be positioned as outlined in the drawing 1 2 Remove the furnace chamber assembly from the furnace cabinet following instructions listed in the installation manual Remove the burner access door Manifold assembly will have to be removed at the valve Remove the burner from the combustion chamber by removing six 6 screws which attach the burner to the chamber and air baffles plates Remove top air baffle and clip Locate the lance in relation to the burner ports for electrode positioning by a Shine a flashlight into the burner venturi as illustrated be sure the flashlight lens is against the end of the burner b Light will reflect off the lance in the venturi of the burner and shine through a position of the two 2 rows of burner ports in the top of the burner c Using a black felt tip pen mark a line along top of
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18. 3 8 5 2 5 in 2 wc 375 Motor 9 423 Motor SF4242F Ducted 40 000 PROPANE 12 0 SFV 20 20F Ducted 20 000 PROPANE 12 VDC 3 8 5 2 wc 3 SFV 25 25F Ducted 25 000 PROPANE 12 VDC SFV 30 30F Ducted 30 000 PROPANE 12 VDC 3 8 5 2 wc 300 SFV 42 42F Ducted 40 000 PROPANE 12 VDC 11 5 25 wc 430 5 3 SHD 2542 Ducted 25 000 PROPANE 12 VDC 3 8 8 Low 25 wc 430 42 000 12 High 00 00 i 22 SEQUENCE OF OPERATION For Furnaces Equipped With Time Delay The thermostat controls the operating circuit to the furnace by reacting to room temperature to open and close a set of contact points which allows current to flow to the ON and OFF switch then to the relay The relay receives the power and allows power to pass through to the switch within the relay This is done by a heater coil within the relay which actuates a bi metal disc closing the relay circuit The power then flows to the motor and allows the blower to operate One end of the motor shaft drives the room air wheel The other end of the motor shaft drives the combustion air wheel that delivers the required air to the burner for combustion The limit switch is an in line device which protects the furnace from over heating conditions The contacts in the limit switch open ata given temperature setting shutting off power to the ignition system which controls the gas valve As the room air wheel comes up to speed air flow closes the sai
19. 5F 25 000 71 2 17 20 Electronic 35 SF 30F 30 000 71 2 17 20 Electronic 35 SF 35F 35 000 71 2 17 20 Electronic 35 SF 42F 40 000 71 2 17 20 Electronic 35 SH 35F 35 000 9 1 4 17 20 Electronic 40 SH 42F 40 000 91 4 17 20 Electronic 42 SF 20 20 000 71 2 17 20 Electronic 35 SF 25 25 000 71 2 17 20 Electronic 35 SF 30 30 000 7 1 2 17 20 Electronic 35 SF 35 35 000 7 1 2 17 20 Electronic 35 SF 42 40 000 71 2 17 20 Electronic 35 SH 35 35 000 91 4 17 20 Electronic 40 SH 42 40 000 91 4 17 20 Electronic 42 SHD 2542 25 40 000 9 1 4 17 20 Electronic 44 Accessories Description 6258ACW Door Optional Access Colonial White Standard SF Models 6258APW Door Optional Access Polar White Standard SF Models 6267ACW Door Optional Access Colonial White Standard SH Models 120 VAC BTU h Shipping Model Furnaces Input Height Width Depth Ignition Weight 40 000 12 1 2 12 23 Accessories Description 050733 Duct Cover 050715 Duct Collar 4 051240 Duct Collar 2 280552 Rain Shield 062164 Bottom Duct Gasket NT 24 30 34SP NT 40 P40 Electronic 070853 Bottom Duct Gasket SF Models Except SF 42 F 520009 Bottom Duct Kit W Gasket NT 24 30 34SP NT 40 P40 520576 Bottom Duct Kit W Gasket SF Models Except SF 42 F SH35 F 520753 Bottom Duct Kit W Gasket and Door SF 42 F 520864 Bottom Duct Kit W Gasket SH 42 F SHD 2542 Wall Thermostats are included with All
20. 7w2 Tos 5201 ORDERED SEPARATELY EXTENSION KITS COME WITH COMPLETE INSTALLATION INSTRUCTIONS Figure 5A up L rH 1 5 0 o 1 294 DIA TYP CAULK BEHIND VENT CAP AS SHOWN TO SEAL BETWEEN EXHAUST AND INTAKE AND TO PREVENT MOISTURE INSIDE FURNACE COMPARTMENT APPLY CAULKING GENEROUSLY AROUND PERIMETER OF VENT CAP AND ACROSS CENTER AS SHOWN CENTER PUTTY STRIP IS ESSENTIAL APPLY CAULKING BETWEEN RV SKIN AND BACK OF RAIN SHIELD POSITION RAIN SHIELD AS ILLUSTRATED APPLY A SECOND LAYER OF CAULKING OVER RAIN SHIELD AND BEHIND VENT CAP AS ILLUSTRATED FOLLOW INSTRUCTIONS FOR CAULKING VENT OUTSIDE SKIN PANEL TUBE INTAKE AIR WITH GASKET REMOVABLE PANEL OF COACH WALL MUST SEAL WATER TIGHT VENT CAP amp EXHAUST TUBE 8 VENT amp EXHAUST TUBE SEE DETAIL SECURE WITH 6 SCREWS GAS CONNECTION REAR SFV 35 ELECTRICAL CONNECTION FURNACE CABINET TUBE AIR INTAKE WITH GASKET GAS CONNECTION FRONT SFV 35F 2 060 le qCUTOUT RFURNACE INSIDE WALL Tm REMOVABLE PANEL RIGHT SIDE 2 2 250 DIA HOLES OF CUTOUT 2 000 MAX WALL THICKNESS ANCHOR FURNACE TO FLOOR USING THE 4 10 X 3 4 SCREWS PROVIDED CUT OUT AS VIEWED FROM INSIDE R V SECURE CABINET MOUNTING BRKTS TO CABINET WITH 2 8 X 1 2 SCREWS Figure 6 BRACKET REAR VERTICAL MDUNTING USE IF POSSIBLE 9 NEVER INSTALL THE EXHAUST TUBE WITH LESS THAN 1 1 4 OVERLAP OR TRAILER S
21. AILOR SKIN VENT TUBE EXHAUST 8 X 2 O D VENT TUBE ASSY INTAKE SEE CHART 1 1 4 MIN OVERLAP k lt a MOUNTING SURFACE 1 2 MIN OVERLAP k PART NO INTAKE TUBE LENGTH ONLY X DIMENSION 2 0 0 3 STANDARD kc 23 3 8 25 5 8 050712 20 0 X5 SPECIAL 25 5 8 TO 27 7 8 2 O D X7 1 4 SPECIAL 27 7 8 TO 30 1 8 NEVER INSTALL THE EXHAUST STANDARD TUBE FURNISHED WITH FURNACE TUBE WITH LESS THAN 1 1 4 THE SPECIAL TUBES IF NEEDED ARE TO OVERLAP OR THE INTAKE BE ORDERED TUBE WITH LESS THAN 1 2 OVERLAP Figure 11 NT 20S 3 1 2 FROM CENTER LINE VENT CAP MUST BE USED ON ALL OF INTAKE TO CENTER LINE INSTALLATIONS OF EXHAUST 9 7 1 2 FROM CENTER LINE OF INTAKE TO FLOOR TWO 21 4 DIA HOLES A S y D 52 INSIDE WALL EXHAUST OUTSIDE SKIN AIR INTAKE FURNANCE b 4 NIME MAXIMUM WALL THICKNESS 3 WASHER NOTE 0 CLEARANCE PERMISSIBLE we AT REAR OF FURNACE FOR A WIDTH 76 GAS FITTING OF 3 MAXIMUM O Spy NU GASKET PEEL OFF PROTECTIVE PAPER TO EXPOSE THE ADHESIVE SURFACE ATTACH GASKET TO WASHER PLACE ANCHOR TO FLOOR WASHER OVER GAS FITTING THE GASKET SHOULD SEAL AGAINST CABINET WHEN GAS FITTING IS THREADED INTO POSITION Figure 12 NT 24 30 34SP P 30S 13 VENT ASSEMBLY INSTALLATION NT SERIES MAXIMUM WALL THICKNESS FOR THIS UNIT IS 2 1 4 SEE FIGURE 4 IF MORE THAN 2 1 4 WALL THICKNESS CAULK BEHIND VENT CAP AS SHOWN
22. CED YELLOW WITH WIRING MATERIAL HAVING TEMPERATURE RATING OF AT LEAST 105 C P 40 340535 Figure 30 Fan Control Board P 40 34 FURNACE REMOVAL To replace parts or service the SUBURBAN family of RV furnaces it is necessary to follow these steps DD 17DSI 1 Turn off gas and power then disconnect gas and power supply at the furnace Label wires as necessary 2 Remove the vent cap assembly by removing applicable screws 3 Remove the cabinet front two 2 screws 4 Remove the applicable screws securing the furnace to the coach floor 5 Remove duct from side of furnace if equipped 6 Remove the furnace from the cabinet area to gain access to combustion chamber and applicable parts 7 Some parts can be accessed without removal of the complete furnace 8 Tore install reverse this procedure 9 applicable wires and perform a leak test on all fittings Perform a drop pressure test NT 12 16 20S Q N Turn off gas and power then disconnect gas and power supply at the furnace Label wires as necessary Remove the vent cap assembly by removing applicable screws Remove the cabinet front two 2 screws Remove the 1 one tie down screw securing the chamber to the cabinet Remove the furnace from the cabinet by pulling chamber outward completely to gain access to all controls and applicable parts To re install reverse this procedure Rewire applicable wires and perform a leak test o
23. F THE ORIGINAL BK BLACK WIRE AS SUPPLIED WITH THE BR BROWN APPLIANCE MUST BE REPLACED 2 RED IT MUST BE REPLACED WITH THE Y YELLOW TYPE 105 C OR ITS EQUIVALENT YX16 30 TGS 200 C 18 AWG WIRE WHITE ELECTRODE CODE COLOR G GREEN BL BLUE lt gt 320 F HYPOLON 7MM WIRE 6660147 6 Sense NT Models With Time Delay TEST THIS UNIT AFTER INSTALLATION TO DO SO MAY CAUSE COMPONENT DAMAGE AND VOIDS WARRANTY OF FURNACE UNIT 100 FIRE CHECKED Frayufeongrol Board SF 20 25 30 35 42F 31 DIELECTRIC HIGH VOLTAGE TEST gt THIS UNIT AFTER INSTALLATION TO DO SO MAY CAUSE COMPONENT DAMAGE AND VOIDS WARRANTY OF FURNACE UNIT 100 FIRE CHECKED DIELECTRIC HIGH VOLTAGE TEST THIS UNIT AFTER INSTALLATION TO DO SD MAY CAUSE COMPONENT DAMAGE AND R RED VOIDS WARRANTY OF FURNACE e und 14 AWG 105 C THERMOPLASTIC FUR 57 42 ONLY 100 FIRE CHECKED Figure 26 Local Flame Sense SF Models With Time Delay 5 24 ALL WIRES ARE 18 AWG UNLESS OTHERWISE SPECIFIED DO HI POT NOTE IF ANY OF THE ORIGINAL WIRES AS SUPPLIED ORANGE WITH THE APPLIANCE MUST BE REPLACED IT MUST ee tag BLACK BE REPLACED WITH WIRING MATERIAL HAVING A BR BROWN TEMPERATURE RATING OF AT LEAST 105 INSTALLATION TO DO SO MAY gt 26 2 CAUSE COMPONENT DAMAGE AND RED VOIDS WARRANTY OF FU
24. ISSIBLE AT REAR OF FURNACE FOR A WIDTH OF 2 25 MAXIMUM GAS LINE SHUT OFF VALVE GAS LINE ELBOW ANCHOR TO FLOOR Figure 17 P 40 15 CAULK BEHIND VENT CAP AS SHOWN TO SEAL BETWEEN EXHAUST AND INTAKE AND TO PREVENT MOISTURE INSIDE FURNACE COMPARTMENT APPLY CAULKING GENEROUSLY AROUND PERIMETER OF VENT 3 1 2 7 CUTDUT CAP AND ACROSS CENTER AS SHOWN CENTER PUTTY THRU COMBUSTIBLE STRIP IS ESSENTIAL CONSTRUCTION MAXIMUM WALL THICKNESS FOR THIS TYPE INSTALLATION IS e 1 4 HEAT SHIELD COLLAR WARNING COLLAR MUST BE ATTACHED TO ASSURE SAFE OPERATION DO NOT REMOVE COLLAR EXHAUST TUBE INTAKE TUBE 3 DIA HOLES CENTERLINE OF FURNACE OUTER SKIN INSTALLATION Figure 18 NT 40 P 40 RETURN AIR Return Air The cabinet that the furnace may be installed in will have louvers or openings for the return air back to the furnace When the furnace is installed it is imperative that the return air louvers on the furnace cabinet opening are not obstructed Usually these furnaces are installed under a counter sofa or bed in order to be out of the way A grille or opening must be built into the cabinetry or into the base area of the sofa or bed Return air from the living area of the trailer is drawn in through the grille and into the return air openings in the furnace cabinet Figure 19 illustrates the return air circulation of the furnace Note Refer to the installation manual
25. KIN THE INTAKE TUBE WITH LESS THAN 1 8 OVERLAP T E 9 E k 3 lt gt X lt 4 4 4 4 UU Z 4 GASKET BOTTOM DUCT MOUNTING BRACKET CABINET MOUNTING PER SIDE _ VENT CAP lor 1 1 2 vent suppLien with Furnace IL 2 520768 4 1 2 7 1 2 520769 STANDARD VENT ASSEMBLY FURNISHED WITH FURNACE SPECIAL EXTENSION TUBES IF 175 7 1 2 9 5205 NEEDED MUST BE ORDERED SEPARATELY EXTENSION KITS COME WITH COMPLETE INSTALLATION INSTRUCTIONS Figure 6A 10 VENT ASSEMBLY INSTALLATION DD SERIES Note Vent cap must be installed on DD furnace when bench testing EXHAUST TUBE CHAMBER 750 15 110 X VENT ASSY x 9 750 TRAILER SKIN MOUNTING SURFACE PART VENT LENGTH X DIMENSIONS 260197 22 24 3 8 260198 8 3 16 24 3 8 26 5 8 260199 10 1 2 26 5 8 29 x NOTE NEVER INSTALL VENT WITH LESS THAN 1 250 OVERLAP BETWEEN CHAMBER EXHAUST TUBE amp VENT ASSY EXHAUST TUBE Figure 7 11 VENT ASSEMBLY INSTALLATION NT SERIES VENT TUBE INSTALLATION TRAILOR SKIN VENT TUBE EXHAUST 8 X 2 OD VENT CAP VENT TUBE INTAKE SEE CHART 1 1 4 MIN OVERLAP ON EXHAUST MOUNTING SURFACE a 1 2 MIN OVERLAP Yc 24 OF INTAKE TUBE INTAKE TUBE LENGTH ONLY X050711 2 0 0 23 4 SPECIAL K 050712 2 O
26. NET OUTSIDE SKIN CAULK ALONG THE EDGE OF THE CUTOUT ALL THE WAY AROUND ANCHOR FURNACE CABINET TO COACH FLOOR 2 PLACES AS ILLUSTRATED BACK OF CABINET MUST BUTT AGAINST THIS EDGE OF THE FRAME DOOR FRAME CAULK BEHIND VENT CAP AS SHOWN TO SEAL BETWEEN EXHAUST AND INTAKE AND TO PREVENT MOISTURE INSIDE FURNACE COMPARTMENT APPLY CAULKING GENEROUSLY AROUND PERIMETER OF VENT CAP AND ACROSS CENTER AS SHOWN CENTER PUTTY STRIP IS ESSENTIAL ELECTRICAL 2 CONNECTION AIR INTAKE TUBE 1 1 WITH GASKET GAS CONNECTION 6 SCREWS SUPPLIED SECURE FRAME TO OUTER PANEL WITH SCREWS DOOR MOUNTING 16 PLACES FURNACE ACCESS DOOR VENT CAP amp EXHAUST TUBE Figure 3 SF TIE DOWN SCREW FURNACE TO CABINET OUTSIDE SKIN CAULK ALONG THE EDGE OF THE CUTOUT ALL THE WAY AROUND ANCHOR FURNACE CABINET TO COACH FLOOR 2 PLACES AS ILLUSTRATED BACK OF CABINET MUST BUTT AGAINST THIS EDGE OF THE FRAME DOOR FRAME CAULK BEHIND VENT CAP AS SHOWN TO SEAL BETWEEN EXHAUST AND INTAKE AND TO PREVENT MOISTURE INSIDE FURNACE COMPARTMENT APPLY CAULKING GENEROUSLY AROUND PERIMETER OF VENT CAP AND ACROSS CENTER AS SHOWN CENTER PUTTY STRIP IS ESSENTIAL ELECTRICAL CONNECTION lt P AIR INTAKE TUBE 7 WITH GASKET GAS CONNECTION 6 SCREWS SUPPLIED SECURE FRAME TO we 4 SCREWS OUTER PANEL WITH SCREWS DOOR MOUNTING 16 PLACES VENT CAP amp EXHAUST TUBE FURNACE ACCESS DOOR Figure 3A SH and SHD 2542 VEN
27. RNACE NU 18 250 C RADIX WIRE UL 3257 UNIT 1004 FIRE CHECKED 340513 Figure 27 Fan Control Board NT 12 16 20S and SE 32 Figure 28 Fan Control Board NT 24 30 34SP and NT 40 SPARK ELECTRODE r ELECTRODE T MODULE BOARD THERMOSTAT gt THERMOSTAT ND SWITCH Q REDUNDANT MODULE VALVE AR A 9 000 0 4 TRANSFORMER 2222 GROUNDING TERMINAL MODULE BD TRANSFORMER o O RELAY SWITCH DISCONNECT CODE COLOR BLOCK 17 K BLACK 115 G GREEN ALL WIRES ARE 18 AWG UNLESS OTHERWISE BROWN SPECIFIED NOTE IF ANY OF THE ORIGINAL Jr 16 30 TGS 150 C 18 AWG WIRE WHITE WIRES AS SUPPLIED WITH THE APPLIANCE gt lt 18 250 RADIX WIRE UL 3257 gt RED MUST BE REPLACED IT MUST BE REPLACED Y YELLUW WITH WIRING MATERIAL HAVING BLUE TEMPERATURE RATING OF AT LEAST 105 C P 30 340534 Figure 29 Fan Control P 30S 33 ELECTRODE LIMIT 0 SWITCH WITCH NC ND THERMOSTAT THERMOSTAT CAPACITOR RELAY SWITCH 115 V AC 115 GREEN ALL WIRES ARE 18 AWG UNLESS OTHERWISE LL A BR BROWN SPECIFIED NOTE IF ANY OF THE ORIGINAL Jr 16 30 TGS 150 C 18 AWG WIRE WHITE AS SUPPLIED WITH THE APPLIANCE gt lt ND 18 250 RADIX WIRE UL 3257 R RED MUST BE REPLACED IT MUST REPLA
28. Suburban RV FURNACES SERVICE MANUAL a division of AIRXCEL Inc DD 17DSI DD 17DSIW NT 12S SE NT 16S SE NT 20S SE NT 24SP NT 30SP NT 34SP NT 40 P 30S 40 SF 20 SF 25 SF 30 SF 35 SF 42 SF 20F SF 25F SF 30F SF 35F SF 42F SH 35 SH 42 SH 35F SH 42F SHD 2542 SFV 35 SFV 42 SFV 35F SFV 42F SUBURBAN MANUFACTURING COMPANY 676 Broadway Street Dayton Tennessee 37321 423 775 2131 Fax 423 775 7015 www rvcomfort com info1 suburbanmfg com TABLE OF CONTENTS Page General Service Information eR Ga ee LEE 3 Furnace Spec Sheet uus daa umum Se ka 4 Installation core GR en a IMPER GE YE Eq 5 Vent Assembly Illustrations 6 16 Air IM stratlons ix RR Pate eo eee veste ede a 16 Ducting ll strati ns gt nut amp ees ride ue sad e pate P 17 Installation Requirements DD NT and P Model Furnaces 18 Installation Requirements SF SH and SHD 2542 Model Furnaces 19 Installation Requirement SFV Model Furnaces 20 Furnace Specifications DD NT P Model Furnaces 21 Furnace Specifications SF SFV SH and SHD 2542 Model Furnaces
29. T ASSEMBLY INSTALLATION SF and SH SERIES SF 20F SF 25F SF 30F SF 35F SF 42F STANDARD VENT INSTALLATION gt INTAKE 1 2 MINIMUM OVERLAP 8 EXHAUST 1 1 4 MINIMUM OVERLAP TRAILER SKIN ul x E 5 ER 5 2 FRONT GAS ZA lt HOOKUP 5 MOUNTING SURFACE Y 77 2 1 WWW FPR AAT X DIMENSION EXTENSION TUBES KIT NO gt NEVER INSTALL THE EXHAUST TUBE WITH LESS THAN 1 1 4 OVERLAP OR THE INTAKE TUBE WITH LESS THAN 0 TO 1 12 4 2 OVERLAP 1 1 2 3 STANDARD VENT ASSEMBLY FURNISHED WITH FURNACE 2 SPECIAL EXTENSION TUBES IF NEEDED MUST BE ORDERED SEPARATELY EXTENSION KITS COME WITH 712710 520551 sd COMPLETE INSTALLATION INSTRUCTIONS Figure 4 SF gt INTAKE 1 2 MINIMUM OVERLAP gt EXHAUST 1 1 4 MINIMUM OVERLAP FRONT GAS HOOKUP MOUNTING SURFACE On Ton gt NEVER INSTALL THE EXHAUST TUBE WITH LESS THAN 1 1 4 OVERLAP O TO 1 1 2 520767 OR THE INTAKE TUBE WITH LESS THAN 1 2 OVERLAP 112 3 3 TO 4 1 2 520768 STANDARD VENT ASSEMBLY FURNISHED WITH FURNACE SPECIAL AAETTO Lin 520780 EXTENSION TUBES IF NEEDED MUST BE ORDERED SEPARATELY EXTENSION KITS COME WITH COMPLETE INSTALLATION INSTRUCTIONS 7 1 2 TO 9 520551 Figure 4A SH VENT ASSEMBLY INSTALLATION SFV CUTOUT AS VIEWED FROM OUTSIDE SPACERS ON LEFT 6 RV OF FURNACE ARE FLUSH WITH LEFT SIDE OF CUTOUT ye N ome i Y 2000
30. d The flame is sensed through the spark wire and electrode Therefore it is essential that the electrode is properly positioned in the burner flame 3 Try Ignition Board If the flame is not sensed after seven 7 seconds a second 15 second purge cycle will begin followed by a second Trial For Ignition sequence After three 3 Trial For Ignition attempts with no ignition of the main burner the module board will de energize the gas valve immediately and blower will run for 3 minutes and then shutdown in lockout If during the heating cycle the limit switch circuit opens and remains open for 5 minutes the module board will go into lock out and shut down the blower motor If this occurs the thermostat will need to be reset for the furnace to operate When the thermostat has reached its set point and the demand for heat ends the gas valve will be de energized and the flame will go out The post purge period of 90 seconds begins When it times out the blower motor output is removed and the blower stops 24 Time Line Description Sequence of Events Thermostat Calls for Heat 15 Seconds Purge Cycle 7 Seconds Ignition Cycle and Flame Sense 2 and 3 Ignition Cycles if Required Heating Cycle 90 Second Shut Down Sequence of Operation for 24 VAC Fan Control Module Board Part Number 520947 The wall thermostat controls the operation of the furnace by reacting to room temperature this allows current to
31. extension 7102 E mail address infol suburbanmfg com GENERAL SERVICE INFORMATION Suburban DYNATRAIL furnaces installed in recreational vehicles are classified as Direct Vent Sealed Combustion Furnaces A forced draft furnace utilizes a sealed combustion chamber which is vented to the outside atmosphere The intake air for combustion is also taken from outdoors and is completely isolated from the room air A motor is used to drive an impeller wheel to draw intake air into the chamber to support combustion and force the exhaust gases through the furnace chamber to the outside atmosphere A second impeller wheel driven by the same motor yet totally isolated from the combustion air is used to circulate room air across the furnace chamber where it is heated The blower then forces the hot air into the living area either through a duct system or through a front grille on the furnace cabinet on direct discharge models Suburban furnaces operate on 12 volt DC power which is supplied either by a 12 volt battery or a converter system A recreational vehicle furnace that is specifically designed for park model trailers operates on 120 volts AC These are designed and tested under the same standards as the 12 volt models Suburban forced draft combustion furnaces used in recreational vehicles are designed for use with Propane gas Although a few recreational vehicle furnaces are approved for use with natural gas one should never attempt to convert such a
32. flow through the On Off switch to the module board The module board must have a minimum 18 volts for normal operation Upon a call from the thermostat the module board thermostat circuit will go active The sail switch circuit is verified as being open The blower output is energized Blower motor starts The module board will then verify that the sail switch circuit is closed and motor is up to speed If this circuit remains open blower motor will run continuously until sail switch closes The module board checks that the gas valve relay contacts which are located on the module board are open before the ignition sequence starts The board has a pre purge timing circuit of approximately 15 seconds This allows the chamber to purge The module board will energize the gas valve and enable the high voltage spark output to the electrode for 7 seconds of ignition time The module board will then check for flame sense to verify successful lighting of the main burner flame Sparking will then be terminated and the gas valve and blower outputs will remain energized If ignition is successful the module board will monitor the flame sense sail switch and limit switch circuits and the thermostat inputs during the heating period The flame is sensed through the flame sence electrode Therefore it is essential that the electrode is properly positioned in the burner flame 3 Try Ignition Board If the flame is not sensed after seven 7
33. ical components and connections are protected from water Wire the furnace direct to the battery when possible Use two wrenches on gas fittings when tightening gas connections Verify voltage of furnace do not use 120 volt AC with 12 volt DC Do not modify the furnace in any way Do not vent the furnace to an outside enclosed porch area or where the vent is covered or obstructed Always meet or exceed minimum duct requirements Also meet the minimum return air requirements Furnace must be installed and vented correctly Refer to the Installation Manual for the specific model furnace Do not install aftermarket components Manufacturing Company a division of AIRXCEL Inc SUBURBAN MANUFACTURING COMPANY 676 Broadway Street Dayton Tennessee 37321 423 775 2131 Fax 423 775 7015 www rvcomfort com E mail info1 suburbanmfg com 2007
34. ight the burner When lockout occurs the spark stops the voltage from the module board to the gas valve is discontinued and the valve closes The unit will remain in lockout and the blower will continue to run until the thermostat is turned off Turning the thermostat off disengages the lockout function of the module board After the blower has stopped the ignition sequence can be started again The module will try three times for ignition before lockout Remove burner and check burner for obstructions Clean as required 4 Burner ignites but goes off and into lockout a Check to be certain that flame sensor is over slots in the main burner and that the main burner flame is burning against the tip of the flame sensor adjust by bending sensor probe NOTE Sensor probe should be in the inner blue cone of the burner flame approximately 1 4 t o 5 16 above burner Burner still goes off and into lockout check wire connections at flame sensor and at module board Wire connections OK check continuity through flame sensor wire Continuity of flame sensor wire OK check with micro amp meter in series with flame sensor and flame sensor wire to be certain that the flame sensor is generating at least seven micro amps within seven seconds after the burner is ignited Connect meter as follows to sensor wire to sensor probe Adjust position of sensor probe check for carbon deposits on sensor probe if reading is less than se
35. l switch completing the circuit The sail switch is placed into the system as a safety to prove there is adequate air for combustion The next operation is controlled by the Direct Spark Ignition DSI system as power is applied to the DSI board The system will do the following 1 The board has a timing circuit which allows the blower to purge the chamber of any products of combustion or gas 2 The board will then apply power to the gas valve At the same time it produces a high voltage power supply to the electrode producing spark at the burner 3 The board will also confirm the presence of a flame If the flame is not sensed after 7 seconds the module will try two 2 more times and then go into lock out The flame is sensed through the spark wire and electrode When the thermostat has reached the set point with the room air temperature the contacts will open removing power from the controls The blower will remain on until the relay opens and stops the motor NOTE On some models sail switch is before limit switch 23 Time Line Description Sequence of Events Thermostat Calls for Heat 15 Seconds Purge Cycle 7 Seconds Ignition Cycle and Flame Sense 274 and 3 Ignition Cycles if Required Heating Cycle 90 Second Shut Down Sequence of Operation for Fan Control Module Board Part Number 520820 The wall thermostat controls the operation of the furnace by reacting to room tempera
36. m of 1 2 on intake and 1 1 4 on exhaust Check your furnace model number for vent installation procedures Vents cannot be altered as supplied from the factory VENT ASSEMBLY INSTALLATION SF and SH SERIES OUTSIDE SKIN PANEL VENT CAP AND TUBE INTAKE AIR EXHAUST TUBE WITH GASKET TUBE AIR INTAKE WITH GASKET CAULK BEHIND VENT CAP AS SHOWN TO SEAL BETWEEN EXHAUST AND INTAKE AND TO PREVENT MOISTURE INSIDE FURNACE COMPARTMENT APPLY CAULKING GENEROUSLY AROUND PERIMETER OF VENT CAP AND ACROSS CENTER AS SHOWN CENTER PUTTY STRIP IS ESSENTIAL DETAIL A REMOVABLE PANEL OF COACH WALL MUST SEAL WATER TIGHT OUTSIDE SKIN PANEL CONNECTION GAS CONNECTION Z INSIDE WALL MAXIMUM WALL THICKNESS FURNACE CABINET Figure 2 SF OUTSIDE SKIN PANEL VENT CAP AND TUBE INTAKE AIR EXHAUST TUBE WITH GASKET VENT CAP AND TUBE AIR INTAKE EXHAUST WITH GASKET CAULK BEHIND VENT CAP AS SHOWN TO SEAL BETWEEN EXHAUST AND INTAKE AND TO PREVENT MOISTURE INSIDE FURNACE COMPARTMENT APPLY CAULKING GENEROUSLY AROUND PERIMETER OF VENT CAP AND ACROSS CENTER AS SHOWN CENTER PUTTY STRIP IS ESSENTIAL 2 2 1 4 DIA HOLES DETAIL A REMOVABLE PANEL OF COACH WALL MUST SEAL WATER TIGHT OUTSIDE SKIN PANEL ELECTRICAL CONNECTION GAS CONNECTION gt INSIDE WALL 2 MAXIMUM WALL THICKNESS FURNACE CABINET Figure 2A SH 6 VENT ASSEMBLY INSTALLATION SF and SH SERIES TIE DOWN SCREW FURNACE TO CABI
37. n all fittings Perform a drop pressure test NT 12 16 20SE Q N Turn off gas and power then disconnect gas and power supply at the furnace Label wires as necessary Remove the vent cap assembly by removing applicable screws Remove the cabinet front two 2 screws Remove the 2 two tie down screws securing the chamber to the cabinet Remove the furnace from the cabinet by pulling chamber outward completely to gain access to all controls and applicable parts To re install reverse this procedure Rewire applicable wires and perform a leak test on all fittings Perform a drop pressure test NT 24 30 34SP and NT 40 N Turn off gas and power then disconnect gas and power supply at the furnace Label wires as necessary Remove the vent cap assembly by removing applicable screws and one 1 flue retaining screw Not applicable to NT 40 Remove the cabinet front two 2 screws Remove the 2 two tie down screws securing the chamber to the cabinet Remove the furnace from the cabinet by pulling chamber outward completely to gain access to all controls and applicable parts To re install reverse this procedure Rewire applicable wires and perform a leak test on all fittings Perform a drop pressure test 35 FURNACE REMOVAL SF 20 25 30 35 42 SFV 20 25 30 35 42 SH 35 42 and SHD 2542 1 Remove the vent cap assembly from the outside access door by removing applicable screws als
38. nace should not be operated until the problem is corrected Two common causes are 1 Restriction in the vent or furnace intake screens wasp nests tape 2 Dirty burner If operation of the furnace continues under these conditions it could result serious injury to the occupants of the RV or even death Cleaning of the main burner and an inspection of the venting system should be done at least once a year preferably just before the beginning of the heating season Some RV owners and service personnel have the false assumption that if a furnace has not been used it will not require cleaning NOT SO A furnace which has not been used for some time could be more in need of cleaning than a furnace which has been used extensively Dust and lint should be removed from the room air blower wheel and sail switch A build up of dustand lint on the blower wheel can cause the motor to drag and not generate enough air flow to engage the sail switch Dust accumulation on the sail switch will restrict the travel of the actuator arm to where the air flow across the paddle will not sail itin and complete the valve circuit A yearly inspection should be made of all gaskets on the furnace If any gaskets show signs of leakage or deterioration they must be replaced TO CLEAN THE CHAMBER THE FURNACE MUST BE REMOVED FROM THE CABINET AND THE MANIFOLD BLOWER ASSEMBLY AND CONTROLS REMOVED LEAVING THE CHAMBER ONLY AS SHOWN USING COMPRESSED AIR BLOW THROUGH
39. nition type problems the electrode should be positioned as outlined in the drawing lt 031 reet 1 1 8 spark gap between electrode and ground 2 Maintain electrode position of 3 16 over burner ports Figure 32 LOCAL FLAME SENSE PARK MODEL ELECTRODE GAP SPECIFICATIONS AND POSITIONING To assure consistent ignition of the burner itis important for the electrode to be positioned properly over the top of the burner When replacing the electrode or should you be experiencing ignition type problems the electrode should be positioned as outlined in the drawing APPROXIMATELY DR TWICE GAP BETWEEN GROUND FLAME me AND ELECTRODE _ 1 1 8 spark gap between electrode and ground 1 p d gt 2 1 4 spark between ground and flame sensor 3 Maintain electrode position of 3 16 over burner ports ELECTRODE Figure 33 REMOTE FLAME SENSE 38 MAINTENANCE Preventative maintenance is essential if an RV owner is to have reliable safe operation of his furnace Two important areas to watch closely in order to assure safe reliable operation are the venting and the main burner An obstruction in the vent or main burner will reduce the combustion air which results in incomplete combustion Whenever incomplete combustion occurs the by products are carbon monoxide CO and soot If the furnace outside exhaust vent shows black soot forming the fur
40. o the four 4 screws retaining the door to the frame Remove the door to gain access to the furnace Turn off gas and power then disconnect gas and power supply at the furnace Label wires as necessary Remove the 1 one tie down screw securing the chamber to the cabinet Remove the furnace from the cabinet by pulling chamber outward completely to gain access to all controls and applicable parts To re install reverse this procedure Rewire applicable wires and perform a leak test on all fittings Perform a drop pressure test SF 20 25 30 35 42F SFV 20 25 30 35 42F and SH 35 42F Q N NO Turn off gas and power then disconnect gas and power supply at the furnace Label wires as necessary Remove the vent cap assembly by removing applicable screws Remove the cabinet front two 2 screws Remove the 1 one tie down screw securing the chamber to the cabinet Remove the furnace from the cabinet by pulling chamber outward completely to gain access to all controls and applicable parts To re install reverse this procedure Rewire applicable wires and perform a leak test on all fittings Perform a drop pressure test P 30S and P 40 Turn off gas and power then disconnect gas and power supply at the furnace Label wires as necessary Remove the vent cap assembly by removing applicable screws and one 1 flue retaining screw Not applicable to P40 Remove the cabinet front two 2 screws Remove the 2 two
41. oisture in the gas bottle regulator or in the gas lines It is difficult to check for these fluctuations that will not noticeably affect any other appliance in the coach However isolating the furnace from the coach gas system will determine ifthe gas system is responsible This isolation procedure can be done by connecting a separate upright bottle regulator and gas line directly to the furnace eliminating the coach gas system If the occasional lockout still exists then the furnace should be thoroughly tested to determine the cause however if the furnace works properly on this separate system then the coach gas system should be checked Check furnace return air and warm air discharge to be certain sufficient air flow is present to engage micro switch every time Check micro switch to be sure it moves freely Remove electrode and burner Clean thoroughly f ALL WIRES ARE 18 AWG UNLESS OTHERWISE When moisture in the gas system is suspected as being the problem especially where the horizontal type gas bottle is being used the following steps should be take to prepare the gas system against further moisture problems Corrective Measures 1 Disconnect gas bottle and drain it completely dry of all gas and all moisture 2 Disconnect and blow out all gas lines completely dry 3 Check pressure regulator on the gas bottle Replace if necessary 4 Add the drying agent One half pint of methanol alcohol per 100 pound bottle capacit
42. r flow and the better the performance of the furnace Avoid making sharp turns in the duct system Sharp turns will increase the static pressure in the plenum area of the furnace and could cause the furnace to cycle on limit The duct connections to the furnace cabinet should be tight to eliminate any heat loss which could result in overheating of the component parts on the furnace as well as a reduction in the heated air flow through the ductwork Figure 20 17 Jeoeds oj si 0 HLON pesn SNP 6 JI 88 o eq e SNP p J PINOYS Z pue uonel ejsu sillu65 eroeds dSr LN dS0 LN dStc LN 995 dS9L LN 995 3SCi LN 502 S9L LN pojeo Lx 88S ISqZL ad 1 S opo youl bs jong epis 9 1 yong dol yong ung sjong SLNAWAYINOAY NOILVTIVLSNI 7 98029 WA sesn 2792 5 27 45 584059 sesn 2745 peunbeu jonp woyog x pesn sjonp 88 pejonpeJ eq sjonp v JI PINOYS Z Jenue N pue uonejeisu 5 1 seBuejJ 490605 eoueJe9 o 0 310 Cx 998 99 6 FAS 2 uGG
43. rmal amp draw M Yes Check for 12vdc at furnace No gt Check on off switch on furnace Yes Y Check fuse or circuit breaker No gt Replace fuse Reset breaker Yes Approximately 10 20 seconds MA Check for 12vdc at time delay relay and ds Blower is operating for 12vdc to red wire leading to the motor Noo Replace the time delay relay Yes Y Yes Check ground wire on terminal block No gt Replace the motor Check plug connection to the After 15 seconds the module No Check for 12vdc between red and Yes gt mModule electrode and wire spark gap 1 8 inch creates spark and opens valve yellow wires at the module board between probe and ground v No M Check for 12vdc at limit switch Yes gt Replace the sail switch both sides Yes No M Check for 12vdc at sail switch Yes gt Replace the limit switch both sides Y Spark occurs for approximately No spark at the electrode 7 seconds and main burner flame No gt No gt Replace the module establishes M Yes Check for 12vdc at gas solenoid No gt Replace the module valve M Yes Did the gas valve open No gt Check gas pressure at the manifold or for restrictions in the burner orifice Yes No M M Yes Check for restriction in Beplac the a s valve combustion air Intake wasps etc 9 3 No Check flame contact to electrode Flame should Is flame established be hard blue Thermostat opens and the time delay
44. th the electrode wire disconnected nor with the electrode assembly removed from the furnace 2 Never use a screwdriver on any part of the electrode assembly while the furnace is in operation 3 Be certain that the spark from the electrode never reaches the flame sensor portion of the electrode assembly The electronic ignition system is made up of three main parts the module board the electrode assembly and the electrode wire The module board is the brain of the electronic ignition system and it has several functions 1 When the blower reaches approximately 75 of the normal r p m and sufficient air flow is established the sail switch engages and completes a 24 volt circuit through the limit switch to the module board 2 After a 12 18 second delay 24 volt current will pass through the module board to the solenoid valve The current to the valve opens it and allows gas to the main burner simultaneously the module board sends high voltage through the electrode wire to the electrode assembly The voltage seeks a ground between electrode and ground probe and a spark occurs The spark then ignites the main burner It is important to determine the type problem being experienced then the proper checkout procedure can be made The following is a list of problems how to identify in which area the problem is located and how to correct it 1 Electrode not sparking with blower running and micro switch engaged check the following
45. ture this allows current to flow through the On Off switch to the module board The module board constantly checks for a minimum 9 5 volts If there is not 9 5 volts the module board will go into a stand by mode until adequate power is supplied It will then resume normal operation Upon a call from the thermostat the module board thermostat circuit will go active The sail switch circuit is verified as being open The blower output is energized Blower motor starts The module board will then verify that the sail switch circuit is closed and motor is up to speed If this circuit remains open for 30 seconds after the blower motor starts the module board will go into lock out and shut down the blower motor The module board checks that the gas valve relay contacts which are located on the module board are open before the ignition sequence starts The board has a pre purge timing circuit of approximately 15 seconds This allows the chamber to purge The module board will energize the gas valve and enable the high voltage spark output to the electrode for 7 seconds of ignition time The module board will then check for flame sense to verify successful lighting of the main burner flame Sparking will then be terminated and the gas valve and blower outputs will remain energized If ignition is successful the module board will monitor the flame sense sail switch and limit switch circuits and the thermostat inputs during the heating perio
46. unit to natural gas unless the conversion is approved by the manufacturer of the furnace Gas Supply Pressure Requirements Line Pressure Minimum 11 WC Maximum 14 WC WC water column Voltage Requirements Voltage DC 12 volt D C Minimum 10 5 volts D C Maximum 13 5 volts D C Service Tools Required Manometer gauge U Tube Volt ohm meter capable of testing above 15 amps Module board tester 641511 Gas leak detector OR approved leak check liquid Assorted wrenches Assorted hand tools Safety glasses Suburban RV FURNACES 12 VDC Direct BTU h Shipping Discharge Input Height Width Depth Ignition Weight NT 12SE 12 000 93 8 9 3 8 21 27 3 4 Electronic NT 16SE 16 000 93 8 9 3 8 21 27 3 4 Electronic NT 20SE 19 000 93 8 9 3 8 21 27 3 4 Electronic DD 17DSI 17 000 12 10 1 2 22 29 Electronic Accessories Description 260197 Vent Kit 2 4 DD Models 260198 Vent Kit 4 6 DD Models 260199 Vent Kit 6 9 DD Models 12 VDC Ducted BTU h Shipping Furnaces Input Height Width Depth Ignition Weight 125 12 000 93 8 93 8 223 4 29 1 2 Electronic 165 16 000 93 8 93 8 223 4 29 1 2 Electronic 27 NT 20S 19 000 93 8 93 8 23 3 8 30 1 8 Electronic 27 NT 24SP 24 000 12 1 2 12 23 Electronic 40 NT 30SP 30 000 12 1 2 12 23 Electronic 40 NT 34SP 34 000 12 1 2 12 23 Electronic 40 NT 40 40 000 12 1 2 12 23 Electronic 42 SF 20F 20 000 71 2 17 20 Electronic 35 SF 2
47. ven micro amps Flame sensor circuit generating at least seven micro amps but still goes off and into lockout replace module oard 5 Repeated module board failures a b 29 Check to be certain that the electrode spark is not sparking against the flame sensor portion of the electrode assembly Check to be sure module board or high voltage wires are not shorted to the chamber wrapper or other furnace parts Be sure insulator covering the electrode wire connection on the coil of the module board is in place and insulator behind module board is in place Make certain that the transformer voltage is within 24 30 volts A C Be sure duct connections to furnace are airtight Seal duct collar connections to furnace cabinet with duct tape if necessary to prevent hot air leakage No air leakage should exist anywhere in the duct system especially at connections on furnace cabinet Be sure sensor wire terminal is tightly affixed to sensor probe Be sure high voltage electrode wire is in good condition and properly positioned onto pierce point electrode 6 Customer complains of unit going into lockout only once in a while a b c d e Thoroughly check electrode and burner relationship Lockout can occur if the gas pressure fluctuates at the time the thermostat calls for heat Pressure fluctuations can be caused by amalfunctioning gas bottle regulator an obstruction or a kink in the gas line or m
48. wer will run for three 3 minutes and then go into lockout mode 2 Stage Heatin If during the thermostat cycle the demand for heat drops below the second stage thermostat setting 3 to 5 degrees variance depending on thermostat manufacturer the blower speed control board will be energized The blower speed control board will energize the additional gas valve solenoid and increase motor speed to the high position Furnace will remain in the second stage operation until thermostat is satisfied 90 Second Shut Down When the thermostat has reached its set point and the demand for heat ends the gas valve will be de energized and the flame will go out The post combustion purge period of 90 seconds begins When it times out the blower motor output is removed and the blower stops 26 TROUBLE SHOOTING GUIDE SUBURBAN RV FURNACES with TIME DELAY 12 VDC HEATING SECTION System Ok Check thermostat wire connections operates the fan for the Replace the time delay relay cool down cycle Yes 27 Clean points secure loose Thermostat closes No gt contact points and the heat Yes gt connections replace thermostat if anticipator Anticipator is shorted M Check 12vdc at blue wire check the Yes gt Replace thermostat amp draw to thermostat Yes No Check for shorts Yes gt Repair or replace connections or parts Check components amperage with higher than no
49. y is recommended Precautions 5 Never fill the gas bottle over 80 6 Do not use the gas bottle completely dry to avoid using up the drying agent We have found the above procedures to be effective in solving most occasional lockout problems especially where the horizontal type gas bottle is used All of these steps must be performed as described for the preparation of a contaminated gas system to be 100 effective 16 30 TGS 150 C 18 AWG WIRE gt lt NH 18 250 RADIX WIRE UL 3257 SPECIFIED NOTE IF ANY OF THE ORIGINAL WIRES AS SUPPLIED WITH THE APPLIANCE MUST BE REPLACED IT MUST BE REPLACED TEMPERATURE RATING AT LEAST 105 C P 30 340473 Figure 21 P 30S with Time Delay 2 hs Vac ALL VIRES ARE 18 AVG UNLESS OTHERWISE NOTE IF HE ORIGINAL BR wires AS SUPPLIED WITH THE APPLIANCE CHEE MUST BE REPLACED IT MUST BE REPLACED LS LVELEDVIVITH WIRING MATERIAL HAVING TEMPERATURE RATING DF AT LEAST 105 C te 16 30 TGS 150 C 18 AWG WIRE lt gt ND 18 250 RADIX WIRE UL 3257 Figure 22 P 40 with Time Delay 30 BL_THERMOSTAT G TIME DELAY RELAY 0 BL THERMOSTAT GROUNDING TERMINAL C Figure 23 BOOED Remote Flame Sense With Time Delay VALVE NOTE IF ANY O
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