Installation and Service Manual E331G
Contents
1. M Damaged 5 Water or Oil Contamination ees R Sequence Valve Gives Erratic Timing Damaged Piston 688 O Excessive Lubrication M Fluctuating Air Pressure P Accumulated R Damaged Gasket D Flow Control Valve Does Not Respond to Adjustment Excessive Lubrication M Incorrect Installation or Dirt in Valve Q 6 ROSS CONTROLS REPAIR PROCEDURES EXHAUST POPPET RESILIENT FACE VALVE SEATS INLET RETURN POPPET SPRING GUIDED STEM Figure 3 Typical Inline Poppet Valve Body MAIN INLET POPPET NOT SEALING Foreign particles may be holding the poppet off its seat Taking appropriate safety precautions cycle the valve sev eral times to see if the flow of air through the valve will flush the particles out If not it will be necessary to disassemble the valve See figure 3 or 4 Follow appropriate lock out tag out procedures Turn off the elec trical power to the valve Shut off the air supply and exhaust the air in the system Disassemble the valve body assembly Inspect the inlet poppet for evidence of dirt particles or damage to the poppet Clean o2. Vacuum or Non Air Service Many ROSS valves can be used for vacuum service or with fluids other than air Such applications require an external pilot supply For more infor mation consult ROSS for Bulletin 440 ROSS Valves for Vacuum Service Pipe Installation To install pipe in valve ports engage pipe one turn apply pipe thread sealant tape not recommended and tighten pipe This procedure will prevent sealant from entering and contaminating the valve MAINTENANCE Pneumatic equipment should be maintained only by per sons trained and experienced in the maintenance of such equipment Supply Clean Air Foreign material lodging in valves is a major cause of improper operation The use of a 5 micron rated air filter located close to the valve is strongly recom mended The filter bowl should be drained regularly and if its location makes draining difficult the filter should be equipped with an automatic drain Check Lubricator Supply Rate A lubricator should put a fine oil mist into the air line in direct proportion to the rate of air flow Excessive lubrication can cause puddling in the valve and lead to malfunctions For most applications an oil flow rate in the lubricator of one drop per minute is adequate Note that the valve does not itself require air line lubrica tion See below for information about lubricants that are compatible with the materials used in the valve and are suit able for use in compress
3. T PLUNGER POSSIBLE DIRT WEAR AREAS SHADING COIL AIR GAP FIELD FRAME Figure 9 Typical Pilot Solenoid 8 ROSS CONTROLS REPAIR PROCEDURES CVLINDER LEAKS See figure 10 Four wav valves sometimes blow to ex haust because of leaking packings in the work cvlinder connected to the valve Before looking for faults in the valve check the cylinder for leaks n the following steps take appropriate safety precautions because both the valve and the cylinder will be actu ated 1 Disconnecttheairline to the end of the cylinder which is not under pressure If air comes out of the open cylinder port the cylinder packings are leaking and must be repaired If there is no leakage reconnect the air line 2 Reverse the position of the valve and disconnect the other air line to the cylinder Again check for air coming out of the cylinder port If there is air coming out the cylinder packings must be repaired 3 If there is no leakage at the cylinder reconnect the air line and proceed with troubleshooting the valve itself INADEQUATE AIR SUPPLY An inadequate air supply volume causes an excessive pressure drop during valve actuation Pilot air pressure may be great enough to begin movement of the valve element but the pressure drop resulting from the filling of the outlet volume depletes the pilot air supply This may result in chattering or oscil lating of the main valve or may simply keep the main valve par ti
4. ROSS ROSS CONTROLS DI VALVE INSTALLATION amp SERVICE MANUAL Manual 331G TABLE OF CONTENTS Page DOUBLE VALVES FOR PRESS CONTROL Service manuals available from ROSS ADDITIONAL AVAILABLE SERVICE INFORMATION nre 3 INSTALEATION NOTES ici rici lirici ivi 4 MAINTENANCE ara 4 5 iii 5 6 REPAIR PROCEDURES 7 10 CONVERSION TO EXTERNAL PILOT SUPPLY rsrerrrriiiiii ii 11 WARRANTY alla 12 ADDITIONAL SERVICE INFORMATION AVAILABLE The installation maintenance and troubleshooting informa RI tion in this Service Manual is intended primarily for use with ROSS single element poppet and spool valves Similar information on double valves for press controls is covered in s A separate service manuals available from ROSS This Service Manual should be a useful guide to solving the problems most likelv to be encountered in a pneumatic jn s system Other valuable guides are the Plate Drawings sf Ss Up Instruction Sheets included in Service Kits and reference Ny pages from the Master Catalog for the particular valve being i serviced A Plate Drawing is a ROSS information sheet giv sE ih iy ing the numbers of repair parts for particular valve models ta 3 me i An Instruction Sheet details the valve installation and ser a ani vice processes The Master Catalog pages offer model a Ra dimensions and standard
5. Follow appropriate lock out tag out proce dures Inspect the seals and replace any that are defective Lubri cate the seals lightly and reassemble the valve To insure long seal life be sure to use only compatible lubricant in the pneumatic system For a list of such lubricants see page 5 VARNISH DEPOSITS IN VALVE See Figures 3 5 or 6 Varnish deposits can cause a valve to act sluggishly or even prevent movement of the valve element altogether especially after a period of inactivity A spool valve frozen in position by varnish can cause a direct acting solenoid to buzz and eventually lead to solenoid burnout Varnish results from the action of oxygen on the lubricating oil and can be aggravated by excess heat Varnish can also come from over heated compressor oil carried over into the air lines Properly lu bricated valves do not usually suffer from varnish deposits To remove varnish use a water soluble detergent or solvent such as kerosene Do not scrape varnish off Also avoid chlorinated solvents trichloroethylene for example and abrasive materials The former can damage seals and poppets and abrasives can do permanent damage to metal parts After cleaning lightly lubricate moving valve parts and reassemble See compatible lubricant chart on page 5 DAMAGED GASKETS A broken or scored web on a valve to base gasket can produce air leakage between ports This can result in unwanted pressurizing of an outlet port or blowing
6. and prevent er rors when ordering future replacements INLINE POPPET VALVES See Figure 1 1 Remove pilot section and adaptor plate from valve bodv 2 Remove pipe plug from external pilot supplv port and reinstall the plug in the internal pilot supplv passage 3 Replace pilot section 4 Attach 1 8 pilot supplv line to external plot supplv port X 1 5 External pilot supplv pressure must be at least equal to the main supplv pressure PILOT EXHAUST Ti ig tt PILOT ia e U i SUPPLY ee ei ice PORT ADAPTOR PLATE INTERNAL PILOT SUPPLY PASSAGE Figure 1 ANSI SIZE 4 10 20 BASE MOUNTED VALVES See Figure 2 Remove valve from base Remove pipe plug from underside of valve body Install pipe plug in internal pilot supply passage Attach 1 8 pilot supply line to external pilot supply port X in base Replace valve on base For poppet valves external pilot supply pressure must be at least equal to the main supply pressure ON I INTERMAL _ PLOT SUPPLY i i Figure 2 ISO SIZES 1 2 amp 3 and ANSI SIZES 1 5 amp 2 5 Base mounted valves See Figures 3 and 4 1 Remove plug from port 14 port 12 on ANSI 1 5 amp 2 5 2 Pipe 1 8 supply line to port 14 3 Pressure in external supply line should be greater than inlet If for any reason the external supply is Ist or drops below inlet pressure the v
7. as it should Also check list of compatible lubricants on page 5 DO NOT LUBRICATE EXCESSIVELY Excess oil can accumulate in low points of the system and restrict the flow of air It can also form pools which will produce a dashpot effect and slow valve action A visible oil fog exhausting from the valve is a sure sign of excessive lubrication Properly lubricated parts should have only a thin film on them For most applications an oil flow rate in the lubricator of one drop per minute is adequate 4 i ALEE TO CHECK BREAK po AT THESE POINTE Figure 10 Cylinder Operated by Four Way Valve WWW rosscontrols com 9 REPAIR PROCEDURES Seals Figure 11 Pilot Section of Valves for Size 1 5 and ISO Bases UNDERSIZE OR PLUGGED SILENCER An undersize silencer or one that is partially plugged restricts the exhaust flow The resulting back pressure can cause erratic motion of poppet valve elements and or cylin ders Remove silencer to see if valve performance is improved Clean silencer and verify that it is of adequate size Do not reinstall an undersize silencer Install cleaned or larger size silencer and check valve performance again CAUTION Restricting the exhaust port of a poppet valve can cause the valve to malfunction Silencers must be resistant to clogging and have a flow capacity greater than the exhaust capacity of the valve ROSS Muffl Air silencers of the proper pipe size fulfill these require ments ROSS ex
8. or restrictions are just a few of the things to be considered when troubleshooting a pneumatic system Consideration of these possibilities can sometimes save an unnecessary valve disassembly job Caution Before disassembling a valve or other pneumatic component or removing it from its installation shut off and exhaust the entire pneu matic circuit and verify that any electrical supply is turned off Follow appropriate lock out tag out procedures www rosscontrols com 5 TROUBLESHOOTING CHART When the valve fails to operate properly check for the Symptoms listed below in the first column For each Symptom several Possible Causes are listed in the second column For each Possible Cause there is a Repair Procedure identified by a letter in the last column These Repair Procedures are detailed in the following pages REPAIR SYMPTOMS POSSIBLE CAUSES PROCEDURE Valve Blows to Exhaust When Not Actuated Inlet Poppet Not 8 A Damaged Seals iii B Damaged Valve to Base Gasket D Gylinder Leaks a Valve Blows to Exhaust When Actuated Damaged Valve to Base Gasket D Damaged Seal ksib Meda csvericed B Damaged SOOO idi Eb F Cylinder Leaks i H Inadequate Air Water or Oil 8 R Solenoid F
9. see below If solenoid passes this check reassemble carefully to eliminate misalignment Burned out solenoid Check the coil for electrical continuity with an ohmmeter and replace the solenoid if the coil is open In spool valves with direct solenoid control varnish deposits may prevent spool mo tion This will prevent full motion of the solenoid plunger and can cause solenoid burnout Solenoids operated in too high an ambient temperature are also sub ject to burnout However the most common cause of solenoid burnout is improper supply voltage See Incorrect Voltage at Solenoid Repair Procedure J If the Solenoid coil is not burned out examine the sole noid for the following three conditions Dirt under the T plunger See Figure 9 Before removing T plunger mark it and the frame so that they can be reassembled with the same orientation Remove T plunger Clean T plunger and frame Before reassembling inspect shading coil and air gap as ex plained below Broken shading coil See Figure 9 Copper shading coils reduce the solenoid s tendency to buzz when operated on alternating current Ifa coil is broken the solenoid must be replaced Wear that causes a loss of air gap There must be a small gap between the solenoid plunger and field frame when the solenoid is energized See air gap Figure 9 If significant wear is apparent under T section the air gap can be lost and the solenoid must be replaced
10. to exhaust A leaking gasket on an inline valve can also produce operating prob lems but is apt to be most noticeable on valves with timed se quence adaptors If the gasket between adaptor and valve body leaks it can bleed off the air which is slowly pressurizing the pis ton so that the timing can be seriously affected Damage to a gasket is most likely to occur during assembly Rarely does a gas ket become defective during normal operation Do not attempt to make do with a damaged gasket It will give trouble sooner or later Replace it RESILIENT SEALS INLET POPPET Figure 4 Poppet Valve Body for Base Mounting Figure 5 Resilient Seal Aluminum Spool Valve Body for Base Mounting www rosscontrols com 7 REPAIR PROCEDURES Varnish Deposits Return Spring Figure 6 Precision Finished Stainless Steel Spool Valve Bodv for Base Mounting BROKEN RETURN SPRING A broken return spring on a spool valve see Figure 6 can cause the spool to remain in an actuated position or to be only partially returned In the latter case several abnormal flow patterns may result depending on the valve configuration If a spool valve has a normal flow pattern only in an actuated position a broken return spring is the most likely cause of the trouble A broken return spring on an inline poppet valve is less likely to preve
11. ails to Actuate Valve But Manual Override Loose Pilot Cover or Faulty Solenoid G Does Actuate Valve Inadequate Voltage at Solenoid J Solenoid Fails to Actuate Valve and Manual Override Damaged Seals i B Also Fails to Actuate Valve Varnish Deposits in C Inadequate Pilot Pressure L Water or Oil 8 R Air Flow is Normal Only in Actuated Position Broken Return E Solenoid Buzzes Damaged Solenoid sirio ina dba G Inadequate Voltage at Solenoid J Varnish in Direct Operated Spool Valve Solenoid Burns Out Varnish in Direct Operated Spool Valve Incorrect Voltage at Solenoid J Pilot Section Blows to Exhaust Loose PilorCovers i G Pilot Poppet Not Sealing K Poppet Chatters Inadequate Air Supply Inadequate Pilot or Signal Pressure L Damaged Silencer i Valve Action is Sluggish Damaged Seals on Spool Valve Varnish in Spool Valve Inadequate Air Supply Inadequate Pilot or Signal Pressure L Inadequate Lubrication
12. air Procedure G PILOT SECTION DIRTV OR DAMAGED INSERT Turn off electrical power to valve Shut off the air supplv and exhaust air in the svstem Follow appropriate lock out tag out procedures Disassemble the pilot section For pilots shown in Figure 7 or 8 remove pilot insert Check action of insert by pressing lightly on the spring protruding from the top Through out its travel about 1 32 inch it should move easily without jerk ing or grabbing If not the insert must be replaced Inspect the poppet and seats for foreign particles or damage If the poppet or upper seat is damaged the pilot insert must be re placed If the lower seat is damaged the entire pilot housing must be replaced Before installing a new insert blow out the pilot air passages to remove any loose dirt particles Reassemble For ISO valves and size 1 5 ANSI valves see Figure 11 Disas semble pilot to remove the plunger Inspect seals on both ends of the plunger as well as the seats against which they seal Anything damaged should be remedied only by replacing the entire pilot assembly INADEQUATE PILOT OR SIGNAL PRESSURE i Pilot or signal pressure below the minimum require ment can produce chattering valve oscillation or slug gish valve action Check your valve specifications for minimum pilot or signal pressure requirements LUBRICATION Some valves require lubrication to operate properly Check the system lubricator to see that it is working
13. ally actuated so that it blows to exhaust Check the pressure drop shown on the gauge at the pressure regulator If the pressure falls more than 10 during actuation of the valve the air supply may be inadequate Inspect the system for undersize supply lines sharp bends in the piping restrictive fittings a clogged filter element or a defective pressure regulator Remember too that the air volume supplied can be insufficient if more pneumatic devices are connected to a circuit than the com pressor is designed to serve INCORRECT VOLTAGE AT SOLENOID ROSS solenoids are rated for continuous duty at 85 to 110 of the voltage shown on the solenoid coil Multi rated solenoids e g 110 120 volts are rated for continuous duty at 85 to 110 of the maximum voltage shown on the solenoid coil A supply voltage that does not fall within this range can result in failure of the valve to shift or lead to solenoid burnout Before checking the electrical supply shut off and exhaust the air supply to the valve Attach a voltmeter to the electrical supply to the solenoid Actuate the solenoid and read the voltage during actua tion If the voltage falls below the allowable operating range the electrical supply is inadequate even though the supply voltage might be correct without the electrical load A voltage that exceeds the allowable operating range can result in solenoid burnout or can cause impact damage resulting in a loss of air gap See Rep
14. alve will switch back to internal pilot supply i Figure 3 Figure 4 www rosscontrols com 11 ROSS CONTROLS P O Box 7015 ROSS ROSS UK Ltd St James Road Brackley Northamptonshire NN13 7XY United Kingdom Telephone 011 44 1280 706668 Fax 011 44 1280 705630 Sr ROSS SOUTH AMERICA Ltda Rua Olavo Goncalves 43 Centro Sao Bernardo Do Campo Sao Paulo Brazil CEP 09725 020 Telephone 011 55 11 9122 2705 In the United States ROSS EUROPA GmbH Robert Bosch Strafe 2 Fax 011 49 6103 7469 4 D 63225 Langen Germanv Telephone 011 49 6103 7597 0 Troy Michigan 48007 U S A Telephone 00 1 248 764 1800 Fax 00 1 248 764 1850 www rosscontrols com Customer Service 1 800 GET ROSS Technical Service 1 800 TEK ROSS ROSS FLEX Service 1 888 ROSS FLX ROSS ASIA KK 10209 5 Tana Sagamihara shi Kanagawa 229 1124 Japan Telephone 011 81 427 78 7251 Fax 011 81 427 78 7256 el ROSS ASIA K K CHINA LIAISON OFFICE Room 17B FuHai Building Printed in the U S A 5 98 288 Huanghe Road Shanghai China Telephone 011 21 6372 2579 ROSS CONTROLS INDIA Pvt Ltd Fax 011 21 6372 2505 B Mount Chambers Fourth Floor 758 Mount Road Chennai 600 002 India Telephone 011 91 44 841 3136 Fax 011 91 44 841 3137 Warranty Products manufactured by ROSS are warranted to be free of defects in material and workmanship for a period of one year from the date
15. eal kit Electrical Contacts In the electrical circuits associated with the valve solenoids keep all switches or relay contacts in good condition to avoid solenoid malfunctions Replace Worn Components In most cases it is not neces sarv to remove the valve from its installation for servicing However turn off the electrical power to the valve shut off the air supply and exhaust the air in the system before be ginning any disassembly operation Follow appropriate lock out tag out procedures TROUBLESHOOTING Troubleshooting is the process of looking at a valve s symp toms e g blowing to exhaust or buzzing solenoid and then relating these symptoms to their most likely causes By care fully analyzing the problem the experienced troubleshooter can quickly isolate the trouble and take appropriate correc tive steps To assist in the troubleshooting process the Troubleshoot ing Chart on page 5 lists most of the common symptoms which valves exhibit and their probable causes Before disassembling a valve to investigate a system mal function check other possible causes of the malfunction Because malfunctions in other components can affect valve action the valve is sometimes blamed for a problem which in fact lies elsewhere We suggest therefore that potential malfunctions in all system components be considered when trouble occurs Leaky cylinder packings poor electrical con tacts dirty filters and air line leaks
16. ed air systems Compatible Lubricants Although most ROSS valves do not require air line lubrication they may be used with lubri cated air being supplied to other mechanisms Some oils contain additives that can harm seals or other valve compo nents and so cause the valve to malfunction The best oils to use are those specifically compounded for air line ser vice These are generally petroleum base oils with oxida tion inhibitors an aniline point between 180 F 82 C and 220 F 104 C and an ISO 32 or lighter viscosity See chart on next page 4 ROSS CONTROLS COMPATIBLE LUBRICANTS BRAND NAME American Industrial Oil 32 Amoco Spindle C Amolite 32 Pacemaker 32 Spinesstic 22 MAKER Teresstic 32 Velocite 10 Air Lube 10H NR Turbo 132 Sunvis 11 Sunvis 722 Regal R amp O 32 Union Turbine Oil Cleaning the Valve If the air supplied to the valve has not been well filtered the interior of the valve may accumulate dirt and varnish which can affect the valve s performance Although ROSS poppet valves are very tolerant of dirty air the valve may sometimes need cleaning To clean the valve use any good commercial solvent or kerosene Do not use a chlorinated solvent or abrasive materials The former dam ages seals and abrasives can do permanent damage to metal parts Reassemble the valve with a gasket and seal kit available from ROSS Lubricate all sliding surfaces with the grease provided in the gasket and s
17. erial in the valve which could prevent the poppet from seating properly See Figure 12 R Accumulations of water or oil have an especially bad effect on devices with small orifices such as timed se quence adaptors Accumulation in such a device can change the effective size of the time orifice or even block it completely See Figure 13 The device must be disassembled cleaned lightly lu bricated and reassembled It may be necessary to install a filter in the supply line to prevent recurrence of the problem FLUCTUATING AIR PRESSURE WATER OR OIL CONTAMINATION Accumulations of water or oil can also occur at low points in pilot supply lines This can result in pressure fluctuations that produce erratic timing The best cure is to eliminate low points Water and oil can also accumulate at low points in a valve and hinder move ment of the valve element perhaps completely preventing its mo tion See Figure 3 This is especially true of a valve operating in a subfreezing environment where accumulated water can turn to ice It is important in such applications to ensure that the supply air is dry and that the air line filter is drained frequently If there is evi dence of excess oil accumulation see Repair Procedure M 10 ROSS CONTROLS CONVERSION TO EXTERNAL PILOT SUPPLV When a valve is converted to external pilot supplv consult ROSS for the converted valve s model number This will allow records and drawings to be changed
18. nt closing of the inlet poppet but should be considered as a possible cause of the valve s blowing to exhaust when not actuated especially in a low pressure application DAMAGED SPOOL If a spool is badly scored or nicked it can allow air to pass from one port area to another This can result in unwanted pressurizing of an outlet port or blowing to exhaust The problem can be further aggravated by the spool s cutting the resilient seals and in creasing the leakage A damaged spool cannot be repaired but must be replaced DAMAGED SOLENOID OPERATION Verify that the supply voltage is correct Refer to Incorrect Voltage at Solenoid Repair Procedure J With the electrical supply to the solenoid shut off check for the following See Figure 7 or 8 Loose pilot cover A loose pilot cover can give the symptoms of a defective solenoid because it prevents full travel of the pilot valve How ever the valve can operate properly if manual actuation is used This is because the gap is closed by the pressure of manual actuation Tighten Figure 8 Pilot Section for ANSI valves size 2 5 20 with Plug in Bases Figure 7 Pilot Section for Inline Valves the cover and check for normal operation Improperly installed solenoid If a solenoid is cocked out of line dur ing assembly perhaps when a replacement solenoid was installed the pilot poppet may be held off its seat so that the valve will not func tion Check solenoid for burnout
19. of purchase ROSS obligation under this warranty is limited to repair or replacement of the product or refund of the purchase price paid solely at the discretion of ROSS and provided such product is returned to ROSS freight prepaid and upon examination by ROSS is found to be defective This warranty shall be void in the event that product has been subject to misuse misapplication improper maintenance modification or tampering THE WARRANTY EXPRESSED ABOVE IS IN LIEU OF AND EXCLUSIVE OF ALL OTHER WARRANTIES AND ROSS EXPRESSLY DISCLAIMS ALL OTHER WARRANTIES EITHER EXPRESSED OR IMPLIED WITH RESPECT TOMERCHANTABILITY OR FITNESS FORA PARTICULAR PURPOSE ROSS MAKES NO WARRANTY WITH RESPECT TOITS PRODUCTS MEETING THE PROVISIONS OF ANY GOVERNMENTAL OCCUPATIONAL SAFETY AND OR HEALTH LAWS OR REGULATIONS IN NO EVENT SHALL ROSS BE LIABLE TO PURCHASER USER THEIR EMPLOYEES OR OTHERS FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES WHICH MAY RESULT FROM A BREACH OF THE WARRANTY DESCRIBED ABOVE OR THE USE OR MISUSE OF THE PRODUCTS NO STATEMENT OF ANY REPRESENTATIVE OR EMPLOYEE OF ROSS SHALL EXTEND THE LIABILITY OF ROSS AS SET FORTH HEREIN Copyright 1998 ROSS CONTROLS Form A10018
20. on To reduce exhaust noise use a silencer such as the ROSS Muffl Air Electrical Conduit Port It is important that the electrical supply be of the correct voltage and Hertz ROSS sole noids are rated for continuous duty at 85 to 110 of the voltage shown on the solenoid coil Multi rated solenoids e g 110 120 volts are rated for continuous duty at 85 to 110 of the maximum voltage shown A supply voltage that does not fall within this range can lead to faulty valve action or solenoid burnout If electrical power is supplied by a sepa rate transformer it must be capable of handling the inrush current of the solenoids without significant voltage drop Operating Pressures and Temperatures Maximum and minimum operating pressures and temperatures are speci fied for each type of valve Staying within these limits con tributes to longer valve life and proper operation If you must exceed these limits consult ROSS for advice on such ser vice Pilot Pressure For proper operation pilot pressure must not fall below the minimum specified for the valve For pop pet valves pilot pressure must be at least equal to the main supply pressure If a solenoid piloted valve must operate at a pressure lower than the minimum specified pilot pressure an external pilot supply of adequate pressure must be used Some ROSS valves automatically accept an external pilot supply while others must be converted to such use as explained on page 11
21. pressly disclaims all warranties and responsibility for any unsatisfactory performance or injuries caused by the use of the wrong tvpe wrong size or inadequatelv maintained silencer in stalled with a ROSS valve DAMAGED PISTON SEAL O Piston seals may be either O rings or the lip seal type If worn or damaged the seal can allow pilot or signal pres MOISTURE DIL sa n e t PROT LINE ASTD lt i Figure 13 Sequence Adaptor ia Adusting krab Figure 12 Flow Control Valve sure to leak by the piston and cause erratic valve response Oper ating problems are apt to be most noticeable on valves with timed sequence adaptors A leaking piston seal can bleed off the pres Surizing air and seriously affect the timing function p If a valve with a timed sequence adaptor suffers from erratic timing the cause can be a fluctuating supplv pres sure Consistent timing requires a consistent supply pressure If the supply pressure varies considerably install a pressure regula tor set at the system s lowest expected pressure and reset the timed sequencer to provide the desired time delay FLOW CONTROL VALVES Flow control valves are most often used to control the flow of air as it is exhausting from a cylinder The flow control valve s flow pattern is indicated on the valve body by an arrow and also by a fluid power diagram Check to be sure the installation is correct If it is check for foreign mat
22. r replace poppet as required If the poppet is swollen or has deteriorated improper lubricants or solvents may be the cause Use only compatible lubricants see page 5 Also check the poppet seat s for dirt and damage If there is dam age to a seat the entire valve body assembly must be replaced If there is no damage to poppet or seat s inspect other parts of valve for damage If there is no other damage clean thoroughly lubricate lightly and reassemble FAULTY SEALS The materials of which seals are made can be attacked by substances such as chlorinated hydrocarbons trichlo roethylene for example and some lubricating oils This can pro duce swelling or shrinking of the seals and result in erratic valve action or blowing to exhaust Swollen seals may cause poppet valves to stick in a partially open position so that the valve blows to exhaust See Figure 3 and 4 Swollen seals on a spool valve see Figure 5 can result in sluggish or erratic valve action or even fail ure of the spool to move at all VALVE SEATS Badly nicked or torn seals can produce blowing to exhaust in valves by allowing air to pass from one port area to another Small leaks in piston poppet seals can affect the timing accuracy of sequence adaptors on inline valves or even render the valve inoperable Before disassembling the valve to inspect the seals turn off the electrical power to the valve shut off the air supply and exhaust the air in the system
23. specification information Most parts are made available in the form of service kits P DT which contain all the parts normallv required for specific service operations A Valve Bodv Service Kit for a poppet valve for example includes the seals poppets springs and gaskets required to service the valve body assembly For copies of these publications or other product data call ROSS or your ROSS Distributor www rosscontrols com 3 INSTALLATION Pneumatic equipment should be installed only by persons trained and experienced in the installation of such equip ment Air lines Before installing a valve in an existing system the air lines must be blown clean of all contaminants which may be in the system It is recommended that a 5 micron air filter be installed in the inlet line close to the valve Valve Inlet DO NOT RESTRICT AIR SUPPLY Any re striction of the air supply lines for example sharp bends or clogged filter element will reduce the speed with which the outlet volume is pressurized and can also cause the valve to malfunction Valve Outlet s For faster pressurizing and exhausting of the outlet volume locate the valve as close as possible to the mechanism being operated Also any restriction in the outlet lines for example sharp bends or undersize lines will reduce both pressurizing and exhausting speeds Valve Exhaust s DO NOT RESTRICT EXHAUST OF POPPET VALVES as this can cause the valve to malfunc ti
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