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 Technical    Trouble Shooting 

Solenoid Valve Trouble Shooting Guide and FAQ

  
  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 solenoid-valve 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. See spare parts list in solenoid-valve 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 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 solenoid-valve 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 solenoid-valve catalogue.

  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 solenoid-valve 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 solenoid-valve catalogue.

  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 solenoid-valve catalogue

Damaged diaphragm base or valve seat

  • Replace valve.
  • Check valve is being used within specification in solenoid-valve catalogue.

Diaphragm inverted

Refit diaphragm correctly or replace with new part. See valve spares in solenoid-valve 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 solenoid-valve catalogue.

Corrosion in pilot orifice

  • Replace damaged components.
  • Check valve specification in suitable for application, see solenoid-valve 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 solenoid-valve catalogue.

Valve Noise Appears Incorrect

Buzz

  • 50 or 60Hz AC buzz. Use DC valve with rectified connector.
  • See connector’s section in solenoid-valve 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 solenoid-valve catalogue. Check pressure and flow.
  • Check solenoid-valve catalogue for more suitable valve for application.
  • Check other items in installation.
  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 solenoid-valves catalogue.
  • Check wiring and wiring diagram
  • Check voltage tolerance, normally +/- 10% consult solenoid-valve 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 solenoid-valve catalogue.

 

Coil Armature Slow

  • 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

 

Media Temperature Too High

  • 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
 

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 lowercase) - 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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