Solenoid Valve Problems & Probably Causes
What do you do if your solenoid valve fails?
Well see below a general guideline table of things to check and consider should this happen to you.
Helpful Hint: Consult your solenoid valve supplier with the application information, details of the fault and how long it was working or if it ever worked from day 1.
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Solenoid Valve Unable To Open
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Failed power supply
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Check if valve is normally closed (power to open) Or Normally Open (Power to close)
Use magnetic detector
Lift coil slightly to check if magnetic field is present.
Do not remove coil if energised as IT WILL BURN OUT
Check contacts
Check wire connections and DIN connector
Check fuses
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Wrong Voltage
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Check solenoid coil marked voltage is correct for supply.
Check voltage tolerances normally +/- 10% however refer to solenoid-valve catalogue.
Some coils work on the principle of creating an inrush condition to open the valve, check your power supply is rated for the coil current requirements.
Most valves will have cable plugs rated to IP65, ensure cable gland and cable diameter are matched, plug connecting screw correctly tightened and allow cable to drop under cable gland to help prevent ingress of water droplets.
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Solenoid Coil burnt out
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Check coil burnt section
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Pressure – Too High
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Check coil power rating, higher power version may be required.
Reduce inlet pressure in line with valve specification with pressure reducing valve.
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Pressure – Too Low
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Check inlet/ outlet pressure difference (Differential) is in line with design conditions of the valve. If too low valve will need replacing with 0 rated or direct acting solenoid valve. Remember that the downstream side will rise to a higher tank or system, so should also be subtracted from the supply side pressure. Other system demands may also reduce the overall supply pressure and further reduce differentials.
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Damaged Armature tube
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Replace armature tube. See spare parts list in solenoid valve store.
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Dirt ingress under diaphragm
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Clean diaphragm or replace if damaged. See spare parts list in solenoid-valve catalogue, maybe fit Y type strainer upstream to filter out suspended particles.
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Dirt ingress in armature tube
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Clean valve armature or replace. Suspended particles of dirt can be filtered out with a strainer, always mount valve with coil upright to reduce wear on the top of the solenoid armature if any dirt gets into the medium. If hard water scale builds up install water softener or dry armature valve from solenoid-valve catalogue, otherwise install Y type strainer to filter out suspended particles.
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Corrosion
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Replace damaged components and check media compatibility with valve.
If the armature is pitted due to Cleaning or dosing fluid? Some acids will attack the 430F stainless armature, which is corrosion resistant but not guaranteed to withstand all fluids.
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Missing components after maintenance
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Replace parts according to spares listing as per solenoid-valve catalogue.
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Solenoid Valve opens slightly Probable Cause
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Low pressure
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Check inlet/ outlet pressure difference (Differential) is in line with valve specification. If too low valve will need replacing with 0 rated version. Remember that the downstream side will rise to a higher tank or system, so should also be subtracted from the supply side pressure. Other system demands may also reduce the overall supply pressure and further reduce differentials.
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Damaged or bent armature tube
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Replace tube with spare parts.
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Dirt ingress under diaphragm
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Clean diaphragm or replace if damaged. See spare parts list in solenoid-valve catalogue, maybe fit Y type strainer upstream.
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Corrosion
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Replace damaged components and check media compatibility with valve.
Do not use EPDM seals on Oils or Fats as the seals will swell and restrict flow. Call technical help line or soak seals overnight to see if it swells up.
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Missing components after maintenance
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Replace parts according to spares listing as per solenoid valve store.
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Solenoid Valve Fails to close or Partly Closes Probable Cause
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Residual power to coil
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Lift coil slightly to check if magnetic field is present.
Do not completely remove coil if energised as IT WILL BURN OUT.
Check wiring and diagram
Check lead connections.
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Dirt ingress in pilot hole under coil armature
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Clean orifice with pin or compressed air.
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Manual over ride
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Check position of manual over ride and adjust if required.
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Pressure pulse upstream.
Pressure difference in/out too high
Outlet pressure occasionally higher than inlet pressure
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Check valve technical data in solenoid-valve catalogue and replace if necessary.
Check pressure and flow
Check other items in installation.
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Damaged or bent armature tube
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Replace tube. See spare parts available in solenoid valve store
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Damaged diaphragm base or valve seat
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Replace valve.
Check valve is being used within specification in solenoid-valve catalogue.
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Diaphragm inverted
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Refit diaphragm correctly or replace with new part. See valve spares in solenoid-valve catalogue.
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Dirt ingress in armature tube
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Clean valve armature or replace. If hard water scale build up install water softener or dry armature valve from solenoid-valve catalogue.
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Corrosion in pilot orifice
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Replace damaged components.
Check valve specification in suitable for application, see solenoid-valve catalogue.
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Valve installed wrong way around
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Check flow direction is in line with flow direction arrow or in/out markings on ports.
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Missing components after maintenance
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Replace parts according to spares listing as per solenoid-valve catalogue.
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Valve Noise Appears Incorrect
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Solenoid Buzz
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50 or 60Hz AC buzz. Use DC valve with rectified connector.
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Water hammer when valve opens
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Caused by high liquid velocity and high pressure through small pipe bore.
Install a closed vertical T piece pipe in before the valve to trap an air pocket to dampen noise.
Reduce inlet pressure.
Increase pipe size to reduce velocity.
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Water hammer when valve closes
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Caused by high liquid velocity and high pressure through small pipe bore.
Ask supplier to reduce closing time of valve. This can be done carefully by increasing slightly (10-20%) the size of the pilot pressure equalising hole in the diaphragm. Too much and valve will not open.
Reduce inlet pressure, Increase pipe size to reduce velocity.
Install water hammer arrestor.
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Difference in inlet/ outlet pressure too high or pulsating pressure line
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Check valve specification in solenoid-valve catalogue. Check pressure and flow.
Check solenoid-valve catalogue for more suitable valve for application.
Check other items in installation.
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Solenoid Coil Burnt / Melted or Cold with Power On Probable Cause
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Wrong Voltage
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Check coil marked voltage is correct with power supply.
Change coil for correct one if required. See coils section in solenoid valve store.
Check wiring and wiring diagram
Check voltage tolerance, normally +/- 10% consult solenoid-valve catalogue.
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Solenoid Coil Short Circuit
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Check remaining installation for short circuit
Check lead connections at coil and DIN connector
Check for moisture in coil, replace as required. Check IP rating according to technical data in solenoid-valve catalogue.
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Solenoid Coil Armature Slow
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Replace damaged armature, see spares section in solenoid-valve catalogue. Check media compatibility with valve.
Bent armature tube, replace accordingly.
Dirt in armature tube, clean and fit Y type strainer
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Media Temperature Too High
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Check media temperature against valve technical data in solenoid-valve catalogue.
Move valve to cooler area or increase ventilation around valve & coil.
Check you have correct function normally closed or normally open
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If all else fails contact the original supplier failing this contact us, we are always happy to help regardless who the original equipment supplier might have been. At the end of the day the working principles are all the same.
