Like all mechanical things with human intervention sometimes solenoid valves fail and stop working for what might seem for no apparent reason. Well, to be honest if a solenoid valve fails there is always a reason, typically it is an application fault whereby the solenoid valve is being used for an application outside the solenoid valve design parameters or the design parameters have changed exceeding the operating boundaries of the installed solenoid valve.
Below is a short-form solenoid valve trouble shooting guide to help users find the reason and remedy for a failed solenoid valve. The table below shows typical failures and remedies but these are only popular suggested solutions, for better accuracy we recommend to speak with your solenoid valve supplier or solenoid valve experts such as ourselves and supply detailed application parameters such as minimum and maximum media operating pressure, minimum and maximum media and ambient temperature, media type, voltage and available volts and amps along with how long the solenoid valve worked before failing and if the solenoid valve failed in energised position or de-energised position etc. All additional information is helpful in providing the correct solution quickly and effectively for each individual solenoid valve application. Other suggestions include ambient moisture levels, corrosive and anti-bacteria cleaners, washes and solvent cleaning schedules and solutions that might be used during installation or maintenance.
Solenoid Valve unable to open Probable Cause
Failed power supply
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
Wrong Voltage
Check 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.
Coil burnt out
Check coil burnt section
Pressure – Too High
Check coil power rating, higher power version may be required.
Reduce inlet pressure in line with valve specification as shown in solenoidvalvesuk catalogue.
Pressure – Too Low
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 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.
Damaged Armature tube
Replace armature tube.
Dirt ingress under diaphragm
Clean diaphragm or replace if damaged. See spare parts list in solenoidvalvesuk catalogue, maybe fit Y type strainer upstream to filter out suspended particles.
Dirt ingress in armature tube
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 solenoidvalvesuk catalogue, otherwise install Y type strainer to filter out suspended particles.
Corrosion
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.
Missing components after maintenance
Replace parts according to spares listing as per solenoidvalvesuk catalogue.
Solenoid Valve opens slightly Probable Cause
Low pressure
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.
Damaged or bent armature tube
Replace tube. See spare parts available in solenoidvalvesuk catalogue
Dirt ingress under diaphragm
Clean diaphragm or replace if damaged. See spare parts list in solenoid-valve catalogue, maybe fit Y type strainer upstream.
Corrosion
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.
Missing components after maintenance
Replace parts according to spares listing as per solenoidvalvesuk catalogue.
Solenoid Valve Fails to close or Partly Closes Probable Cause
Residual power to coil
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.
Dirt ingress in pilot hole under coil armature
Clean orifice with pin or compressed air.
Manual over ride
Check position of manual over ride and adjust if required.
Pressure pulse upstream.
Pressure difference in/out too high
Outlet pressure occasionally higher than inlet pressure
Check valve technical data in solenoid-valve catalogue and replace if necessary.
Check pressure and flow
Check other items in installation.
Damaged or bent armature tube
Replace tube. See spare parts available in solenoidvalvesuk catalogue
Damaged diaphragm base or valve seat
Replace valve.
Check valve is being used within specification in solenoidvalvesuk catalogue.
Diaphragm inverted
Refit diaphragm correctly or replace with new part. See valve spares in solenoidvalvesuk catalogue.
Dirt ingress in armature tube
Clean valve armature or replace. If hard water scale build up install water softener or dry armature valve from solenoidvalvesuk catalogue.
Corrosion in pilot orifice
Replace damaged components.
Check valve specification in suitable for application, see solenoidvalvesuk catalogue.
Valve installed wrong way around
Check flow direction is in line with flow direction arrow or in/out markings on ports.
Missing components after maintenance
Replace parts according to spares listing as per solenoidvalvesuk catalogue.
Valve Noise Appears Incorrect
Buzz
50 or 60Hz AC buzz. Use DC valve with rectified connector.
See connector’s section in solenoidvalvesuk catalogue.
Water hammer when valve opens
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.
Water hammer when valve closes
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.
Difference in inlet/ outlet pressure too high or pulsating pressure line
Check valve specification in solenoidvalvesuk catalogue. Check pressure and flow.
Check solenoid-valve catalogue for more suitable valve for application.
Check other items in installation.
Solenoid Coil Burnt / Melted or Cold with Power On Probable Cause
Wrong Voltage
Check coil marked voltage is correct with power supply.
Change coil for correct one if required. See coils section in solenoidvalvesuk catalogue.
Check wiring and wiring diagram
Check voltage tolerance, normally +/- 10% consult solenoidvalvesuk catalogue.
Coil Short Circuit
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 solenoidvalvesuk catalogue.
Coil Armature Slow
Replace damaged armature, see spares section in solenoidvalvesuk catalogue. Check media compatibility with valve.
Bent armature tube, replace accordingly.
Dirt in armature tube, clean and fit Y type strainer
Media Temperature Too High
Check media temperature against valve technical data in solenoidvalvesuk catalogue.
Move valve to cooler area or increase ventilation around valve & coil.
Check you have correct function normally closed or normally open
Water Hardness the affects on Solenoid Valves.
Hard water under a threshold of 20-25 French degrees the valve should not be affected by scale build ups provided that the system undergoes regular servicing. Nickel plated bodies and covers offer a better response. If you are aware of possible scale build ups then you should have equipped the plant with a water softening system, since water treatment is the only solution to be recommended.
French degrees (°f) (shares symbol with degree Fahrenheit, but in lower-case) - conversion to mg/L calcium: divide by 0.25 One degree French corresponds to one part calcium carbonate in 100,000 parts of water.
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