Solenoid Valve failing to close correctly or only partially closes?

By Admin on Fri 12 May 2017 in Troubleshooting

A quick and simple guide to troubleshooting your solenoid valve. The possible causes for your valve not closing correctly are listed below alongside instructions of how to resolve the issue.

Residual electrical power to coil    

  • Lift the solenoid coil slightly (do not remove completely as coil will burn out quickly) to feel if there is residual magnetic field.
  • Check wiring
  • Check lead connections
  • Remove electrical DIN connector from coil to isolate coil.

Dirt Ingress under diaphragm or seal.   

  • Isolate the solenoid valve
  • Remove the power supply
  • Drain system and carefully remove solenoid valve diaphragm avoid loosing small parts or internal springs, remember seal position or take a photo so new seal is installed correctly.

Manual Over Ride Facility

  • Check the position of the manual over ride and adjust accordingly.

Upstream pressure pulse

  • Check inlet and outlet pressure differential and flow are correct for the solenoid valve being used.
  • Check other valves downstream in the system are not generating excess back pressure.

Pressure difference inlet/outlet too high

  • Reduce inlet pressure or install pressure reducing valve.
  • Install correct solenoid valve to meet the system pressure requirements.

Outlet pressure sometimes higher than inlet pressure

  • Install non return valve downstream of solenoid valve to prevent back flow.
  • Check pressure control valves in system are correctly set up.
  • Install bi-directional solenoid valve, coaxial valve or angle seat piston valve that are designed to control flow in both directions.

Bent or disfigured armature tube

  • Isolate electrical supply
  • Drain system
  • Carefully remove armature assembly, which will have small internal parts and replace.
  • Install a well ventilated guard to protect the solenoid valve.

Damaged diaphragm base or valve seat   

  • Replace solenoid valve.
  • Check solenoid valve is in accordance with system requirements.

Inverted diaphragm    

  • Isolate the solenoid valve
  • Remove the power supply
  • Drain the system and carefully remove solenoid valve diaphragm, avoid loosing small parts or internal springs and install new seal correctly.

Dirt Ingress in solenoid valve armature tube   

  • Isolate the electrical supply
  • Drain the system
  • Carefully remove armature assembly, this will have small internal parts.
  • Clean armature assembly or replace.
  • Install a filter, such as our RPE filter assembly to remove debris in media and/or try to mount solenoid valve with armature vertical so any small particle debris will tend to gravitate down and flush out.
  • If the armature assembly has lime scale build-up due to hard water it is advised to install a water softener into the system to prevent lime scale in all systems.

Corrosion in pilot orifice

  • Isolate electrical supply drain system and replace damaged components.
  • Check solenoid valve specification is suitable for the application.

Solenoid valve installed wrong way around     

  • Check that the solenoid valve flow direction in in line with the system flow requirements, typically solenoid valve is marked inlet and outlet, flow arrow or port 1 (IN) and port 2 (OUT).
  • Pressure assisted solenoid valves usually have their coil mounted over the outlet.
  • View internal thread of valve as outlet is typically deeper/longer than inlet side.

Lost components during maintenance  

  • Replace components according to manufacturers spares listing.
  • Try to remove any parts carefully and it is helpful to use your phone camera as a reference for he re installation procedure.