DIY Doctor UK DIY Forums

My motorised valve keeps sticking in the open position.My cental heating system (Y-type) then needs a new valve every 1-2 years. I have only used a Honeywell 4073 each time it has been replaced. Is there a problem with this valve? Any ideas as to what is causing the problem?

When the valve was replaced, was only the motor changed?. If so there may be some obstruction in the valve body. Try changing the whole valve.
Has the system been flushed through ( to remove debris) and inhibitor added. Is the inhibitor old and needing replacement.

Thanks roger196. but whole valve (motor and body replaced each time. System is clean and contains good inhibitor. A sharp tap on valve body quickly releases valve but frequency of sticking increases until it is every time the valve opens. This has happened over the life history of at least 4 valves. ???

Has the system been cleaned? Flush the system before adding inhibitor. Is the system fed from a tank or a sealed system?

Must admit this is a new one on me. The only time I have seen a valve jam in this way is when dealing with too high a pressure and the ball is pushed too deep into the seat. So are we talking about a standard low pressure system or not?

Has any of the damaged valves been stripped? Is there any evidence of damage to the ball?

Difficult one this. Two possible thoughts.
1 Was the valve actually changed as opposed to you being charged for the change?
2 Is there an intermittent fault in one of the wires to the valve. Likely causes are a break in the wire or a loose connection in the wiring box. If you are OK with electricity, try tightening all connections, otherwise call ina professional. Remember this is mains voltage, so isolate circuit beforehand.