Central Heating bypassing timer programmer

[AlyBu]

My central heating boiler appears to be working from the room thermostat only - switching itself and the radiators on and off at all hours and totally overriding the electrical programmer. When the programmer lights are out the boiler still works! I have to switch it on and off manually at the fuse box. My electricaian says it is a plumbing problem. The plumber says it is an electrical fault. Neither can solve the problem. Any ideas? The boiler is a Halstead "Best" 40. Thanks.

 

[wilhelm]

motorized valve head.

with the caveat...i aint got a clue what a halstead best 40 looks like.

sounds good though. i like ford tdci

 

[ChrisR]

If it's wired conventionally it couldn't be the MV head, but could be the programmer contacts stuck shut.
Let me guess it's a Landis and Gyr (RWB7?), black body silver plate on the front - the one with the little orange rectangular lights for CH and HW?

 

[wilhelm]

aha, glad i put that caveat

ill keep me schnarrzer outa gas me thinks

 

[AlyBu]

It's got orange rctangular lights but it is a siemans.

 

[chrishutt]

My electricaian says it is a plumbing problem. The plumber says it is an electrical fault.

Get in a heating engineer. He will understand the system and won't pass the buck.

 

[AlyBu]

Is a heating engineer different to a plumber?

 

[chrishutt]

Your plumber doesn't (apparently) understand the electrical side of the heating controls. A heating engineer would.

 

[AlyBu]

Got Heating Engineer coming in the New Year. Thinks it could be a problem with the frost stat kicking in and then sticking.