Troubleshooting Solenoid Valves

There are some faults in the actual installation and application of pilot-operated solenoid valves. For example, the pilot-operated solenoid valve doesn’t work properly, has lower fluid transmission efficiency, and has leakage or noises. What causes it? Maybe it is due to selecting a wrong model, inconsistency between the medium density and temperature and the valve, improper installation and so on.

The following is listed some problems of pilot-operated solenoid valve and the possible causes and troubleshooting.

1. After power on, the solenoid valve fails to open (NC type) or close (NO type).

Possible causes:

Poor contact of power supply wiring.
The voltage variation of power supply is out of the allowable range.
The solenoid/coil is short-circuited or burned out.

Troubleshooting methods:

Connect the power cord well.
Adjust the voltage within the allowable range.
Replace the broken solenoid/coil.

2. The fluid cannot flow through when the solenoid valve is open.

Possible causes:

The fluid pressure or the working pressure difference does not meet the pilot-operated solenoid valve’s requirement.
The fluid viscosity or temperature does not match with the valve’s parameters.
The valve core and moving iron core are mixed with impurities.
The filter in front of the valve or the pilot valve hole is blocked.
Working frequency is too high or the service life is expired.

Troubleshooting methods:

Adjust the fluid pressure or working pressure difference.
Replace the suitable pilot-operated solenoid valve.
Disassemble the solenoid valve and clean the inside. Install the filter before the valve.
Clean the filter or pilot valve hole in time.

3. The fluid cannot be cut off when the solenoid valve is closed.

Possible causes:

The fluid viscosity or temperature is not suitable.
Spring is deformed or to the end of life.
The valve seat is defective or some dirt adheres to the seat.
The sealing gasket is out of its place, defective or deformed.
The balance hole or throttling hole is blocked.
Working frequency is too high or the service life is expired.

Troubleshooting methods:

Replace an appropriate solenoid valve.
Replace the spring.
Clean the valve seat, grind or update the gasket.
Reassembly the solenoid valve and clean it in time.

4. The external leakage of solenoid valve

Possible causes:

The connection of pipe is loose, or the outer seal of pipe connection is damaged.

Troubleshooting methods:

Tighten the bolts or pipe threads or replace the seal.

5. The internal leakage of solenoid valve

Possible causes:

Fluid temperature does not conform to the valve’s specifications.
There are impurities or defects between the pilot valve seat and the main seat.
The sealing gasket may slip out of the pilot valve and the main or the gasket may be deformed. The spring is assembly poor, deformation or expiration of life.
Working frequency is too high.

Troubleshooting methods:

Adjust the fluid temperature or replace suitable solenoid valve.
Clean the solenoid valve or grind and repair the gasket if possible.
Replace the gasket or replace the spring if necessary.

6. There is excessive noise when the solenoid valve is energized.

Possible causes:

The fastener is loose.
The voltage fluctuation is not within the allowable range.
The fluid pressure or working pressure difference does not fit.
The fluid viscosity may not match.
There are impurities in the suction surface of the armature.

Troubleshooting methods:

Try to tighten the fastening parts.
Regulate the voltage to the proper range.
Adjust the pressure or working pressure difference or replace the valve.
Clean away the impurities in time.