Solenoid Valves Trouble Shooting Guide & FAQ from Connexion UK 0800 808 7799

Valve unable to open Probable Cause

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� � 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

Connexion Developments are exclusive Solenoid Valve Distributors for Shako Fluid Power Ltd, CS Fluid Power Ltd., Z-Tide, ERA-SIB, Nass Magnet, Queen and DS Dynatec. If you need a valve for a special application make Connexion Developments your first choice: if we can't find the answer straight away then we will find one.

Solenoid Valves For Vacuum or Low pressure applications such as header tank pressures or closed loop systems with little or no differential pressure across the valve we use a "Zero Rated" Solenoid Valve. These will work with zero or little pressure differential.
There are two main types of Zero Rated Solenoid valves "Direct" and "Assisted".

An "Assisted" Solenoid Valve has an attachment from the armature that mechanically lifts the diaphragm or piston off its seat thus causing the valve to open even if there is no or little pressure from the media - Good for Zero to Medium Pressures with good flow capabilities.

A "Direct" Solenoid Valve uses the armature directly over the valve seat as the mechanical means to Directly open and close the valve regardless of the media pressure - Good for High Pressures with normally Lower flow capabilities.

A Solenoid Valve for high pressure or vent to atmosphere applications can use a "Servo Assisted" or "Pilot Operated" Solenoid Valve sometimes called a "Diaphragm" valve.

A "Servo Assisted" or "Pilot Operated" Solenoid Valve uses the pressure difference across the Solenoid Valve (Difference In Pressure from the inlet to the outlet ports) to do the mechanical work of lifting the diaphragm or piston.
This is achieved by controlling the pressure above the diaphragm or piston via a pilot system that can release this pressure through to the outlet port of the valve down stream. The inlet pressure can then overcome the now reduced pressure above the piston or diaphragm forcing it to lift open allowing flow and vice versa.

Most valves of this design require between 0.2 to 2 bar pressure difference to operate correctly, normally about 10% of the working pressure.

Choice of valve size is of paramount importance in achieving the correct pressure differential as too much or too little could adversely affect the operating function of the valve.

Solenoid Valve not working, try our simple guide below