Solenoid valves - problems and solutions

Possible cause

Solution

No voltage on coil

Check whether the valve is open or closed de-energized (NO or NC): 
1. Use a magnetic detector
2. Lift the coil slightly and see if it resists - the coil must not be removed under voltage, otherwise it could burn out.
Check relay contacts. Check the wire connections. Check fuses.

Incorrect voltage / frequency

Check that electrical requirements for the coil are the same as power supply. Measure voltage on the coil.

Permitted voltage deviations:

+/- 10% for dual frequency;

Applications with direct current and NO + 10% / - 15% for alternating current, single-frequency voltage. If necessary, replace the coil with the correct version.

Differential pressure too high

Check the coil info. If necessary, replace the coil with the correct one. Reduce the differential pressure, for example by reducing the inlet pressure.

Differential pressure too low

Check the coil info including the differential pressure. If necessary, replace the coil with the correct one. 

Damaged or bent tube

Replace the valve.

Impurities on the diaphragm

Clean the diaphragm. If necessary, replace defective components.

Dirt in the armature or in the tube

Clean the valve. If necessary, replace defective components.

Corrosion

Replace defective components

Missing components after valve removal

Supply missing components

Possible cause

Solution

Differential pressure too low

Check the coil info including the differential pressure. If necessary, replace the coil with the correct one.

Damaged or bent tube

Replace the valve.

Impurities on the diaphragm

Clean the diaphragm. If necessary, replace defective components.

Dirt in the armature or in the tube

Clean the valve. If necessary, replace defective components.

Corrosion

Replace defective components.

Missing components after valve removal

Supply missing components.

Possible cause

Solution

Humming

Humming caused by alternating current frequency. It can be removed by replacing it with a rectifier coil.

Hydraulic shocks when opening the valve / Hydraulic shocks when closing the valve

Hydraulic shock is a typical result of high fluid velocity. There are several solutions to this problem:

1. Pressure reduction by installing a pressure reducing valve in front of the solenoid valve. If possible, increase the tube diameter.

2. Reduction of hydraulic shock by installing a flexible hose or flexible bumper in front of the solenoid valve

Differential pressure is too high / pulsation in the pressure line

Check valve info, incl. differential pressure. Check fluid pressure and flow. Replace the valve with a more suitable type of valve. Check other installation components.

Possible cause

Solution

Voltage remains on the coil

First, lift the coil slightly to see if it resists. Note: The coil must not be removed under voltage, otherwise it could burn out. Check the wiring according to the wiring diagram. Check relay contacts. Check the wire connections.

Dirt in the orifice / leveling nozzle

Clean it with a needle or similar object (max. Diameter 0.5 mm). Blow out the hole with compressed air. If necessary, replace defective components.

The manual opening unit cannot be screwed back on after use

Check the position and adjust it as required.

Pulsation in the pressure pipe. The differential pressure is too high in the open position. The pressure on the outlet side is periodically higher than the pressure on the inlet side.

Check valve info. Check fluid pressure and flow. Replace the valve with a more suitable type of valve. Check other installation components.

Damaged or bent armature tube

Replace the valve.

Defective valve spring, diaphragm or valve plunger.

Check fluid pressure and flow. Replace the defective components.

Diaphragm in inverted position

Check that the valve is installed correctly.

Dirt in the armature or in the tube

Clean the valve. If necessary, replace defective components.

Corrosion in the orifice

Replace defective components.

Valve incorrectly mounted

Check the direction of fluid flow and make sure the arrow is pointing in the same direction.

Missing components after valve removal

Supply missing components.

Possible cause

Solution

Incorrect voltage / frequency

Check the coil data. If necessary, replace the coil with the correct type. Check the wiring according to the wiring diagram. Check the maximum voltage deviations.

Voltage tolerances: +/- 10% for dual frequency, DC applications, +10% or -15% for AC, single frequency voltage

Coil shorted (there may be moisture in the coil)

Check other components for possible short circuits. Check the connection of the wires to the coil. When a fault is found, replace the coil. Consider mounting a snap-on coil with an additional O-ring body seal (only for the high-performance range of valves).

Prolonged flow through the valve

1) Damaged or bent tube

2) Damaged armature

3) Dirt in the armature tube

Replace defective components. Clean dirt.

Medium temperature too high

Check that the valve and coil data match the installation parameters. Replace with a suitable type of coil or valve.

Temperature too high around the valve

If possible, move the valve to a cooler place. Check that the valve and coil data match the installation parameters. Increase ventilation around the valve and coil.