Noisy motorised valve

[Keonner]

My Central Heating system is only 4 years old. Every so often, a noise (like a horn being blown)comes from the boiler area (worcester bosh) On checking while the noise is still there I found that a motorised valve just below the boiler is vibrating and if held quietens the noise considerably. The noise can last for anything from 10 secs to 1 min. This can happen 6 times a day. A neighbour stated that it was a faulty relay or something on the motorised valve and gave me a spare one that he had. (it appears the same - Honeywell with the same lugs etc. I can't check the numbers until the old one is taken off)
How do you replace the part?. There appears to be only 1 screw holding it in place. Are there any precautions to be taken other than isolating the electicity?
Thanks

 

[gas4you]

Write down where each coloured wire is connected from the valve head before removing.

 

[Keonner]

Hi Dave,
Thanks for in info. The colour of the wires(both of them) on the replacement valve I have are orange but he colour of the wires on the faulty one on the valve are blue. (both of them). It looks like the same valve but this wire colouring has put doubt in my mind.
If the one apparent holding screw is released, does the unit just pull off the valve and the replacement just push on (engaging the little gear)?
Thanks,
Keonner

 

[gas_man_gaz]

sounds like he's given ya a synchron motor

 

[cjb1971]

It sounds like you have been given a replacement synchro motor head,isolate the electric and repleace the old one with the new one and see if it solves the problem,but usually when its the motor what has gone the bolier will not fire up,i think you may be looking at replacing the whole head of the valve if this doesnt work.

 

[gas_man_gaz]

if it is a honeywell valve and ya want to replace the whole actuator make sure its got just 1 dimple on the cover

 

[Keonner]

Hi Everyone,
Thanks for the advice. I have replaced the synchron valve today as suggested and survived. So far there hasn't been any further noise so keeping my fingers crossed that it has sorted the problem out. Thanks again.
Keonner