Page 31 of ASCO Solenoid Valves by Lesman Instrument Company

solenoidvalvetroubleshootingguide problem valve will not operate when valve circuit is energized valvetype direct-acting possiblecause low voltage or no voltage to solenoid coil burned-out coil excessive foreign matter jamming core in core tube binding core or damaged core tube excessive fluid pressure pilot-operated probablesolution check voltage at coil for most valves voltage should be at least 85 of nameplate rating see coil failure below clean valve install strainer close to valve inlet replace parts reduce pressure to valve nameplate pressure rating or install suitable valve same causes and solutions as for direct-acting valves plus low pressure drop across valve ruptured diaphragm or piston ring plugged or restricted pilot orifice valve might be oversized replace valve with one having a smaller orifice increase pressure if possible replace damaged parts clean valve and pilot orifice direct-acting coil not de-energized excessive foreign matter jamming core in core tube damaged disc or seat causing internal leakage binding core or damaged core tube damaged spring check electrical control circuit clean valve install strainer close to valve inlet replace with new parts replace with new spring never elongate or shorten spring pilot-operated same causes and solutions as for direct-acting valves plus damaged pilot seat or pilot disc damaged diaphragm or piston damaged pilot spring insufficient pressure drop across valve replace with new parts replace with new spring never elongate or shorten spring valve might be oversized replace valve with one having a smaller orifice increase pressure if possible problem wire drawing dirt or foreign matter is lodged on seat replace valve body or install new valve install suitable strainer close to valve inlet problem coil failure overvoltage damaged core or core tube causing inrush current to be drawn continuously excessive foreign matter jamming core in core tube causing draw of inrush current excessive fluid pressure causing inrush current to be drawn continuously excessive ambient or fluid temperature missing solenoid parts reduce pressure or install suitable valve class a coils are limited to ambient temperatures of 77° f for temperatures up to 167°f use class f coils for temperatures up to 212° f use class h coils install missing solenoid housing and other metal parts or properly install incorrectly assembled metal parts the housing and other metal parts for part of the magnetic circuit and are required to provide the impedance needed to limit current draw waterproof the entrance conduit to prevent entry of moisture if valve is mounted outdoors check to see that enclosure is weatherproof and that gaskets are in good condition use appropriate sealant where required if general-purpose enclosure is used in a damp or humid atmosphere use watertight molded coils check voltage at coil voltage must conform to nameplate rating check for damaged core core tube or damaged spring check for scale or foreign matter on core or inside core tube clean thoroughly and replace damaged parts moisture inside solenoid enclosure in red-hat ii explosion-proof solenoids a binding core high-input voltage or excessive ambient or fluid temperature may cause the solenoid s non-resettable thermal fuse to open if this occurs the solenoid must be replaced parker tubing and tube fittings asco solenoid valves pressure gauges plugged bleed orifice bleed orifice thermometers problem valve will not close or shift when valve circuit is de-energized pressure and temperature switches process control accessories illinois indiana iowa and sw michigan phone 800-953-7626 · 630-595-8400 fax 630-595-2386 v 08.2006 lesmaninstrumentcompany www.lesman.com sales@lesman.com wisconsin and upper peninsula michigan phone 800-837-1700 · 262-923-1790 fax 262-923-1797 solenoid valves 395

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