Solenoid Valve only opens slightly

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 opening correctly are listed below alongside instructions of how to resolve the issue.

Low Pressure

  • Check inlet and outlet pressure differential (difference) are correct for the solenoid valve being used. Pressure assisted, pilot or servo assisted solenoid valves must have at least 0.3 to 1 bar pressure difference to operate.
  • If the pressure difference between the inlet and outlet pressure is too low replace valve with a zero rated or assisted lift direct acting type or reduce the back pressure to the valve to achieve the required pressure differential. Keep in mind reducing bushes, control valves, pipe bends and vertical pipes all generate back pressures.

Bent or disfigured armature tube     

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

Dirt Ingress under diaphragm or seal.

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

Corrosion   

  • Isolate electrical supply
  • drain system and carefully remove armature assembly, which will have small internal parts and replace.
  • Check media compatibility with the solenoid valve. Is the armature is pitted due to cleaning or dosing fluids? Remember acid and alkali cleaning solutions will corrode the stainless steel armature and care must be taken to dilute any cleaning chemicals BEFORE being used. Pouring concentrated cleaning chemicals into any system and then trying to mix with water afterwards will not correctly dilute all of the chemical which will become trapped and cause severe corrosion in armature assemblies and other dead end circuits.

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 the re-installation procedure.