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.

Torn or Split Diaphragm.

• 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 the seal position (take a photo) so the new seal is installed correctly.
• Inspect the diaphragm for splits or tears, a split in the outer part of the diaphragm may still allow the valve to operate, but because the diaphragm is not opening correctly will reduce the maximum flow through the valve.
• A split or tear in the inner part of the diaphragm may make it impossible to completely close the valve and it will let by.

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.