Halstead Best 50 won't turn off.

[Mikey21]

Hi all

I'm after a bit of advice, a few weeks ago I had the hot water on and after the programmer turned off the boiler stayed on and was venting into the central heating header tank as the pump wasn't running. The only way to turn it off was to turn the power off at the fuse box.

If power is reconnected the boiler fires up but the pump live from the boiler is dead.

It's a Halstead Best db 50, on a fully pumped 'Y' plan with a Honeywell 3 way motorised valve. I replaced the valve head as someone advised me it could be a dodgy micro switch but that made no difference.

Done I bit more checking and the boiler fires up even if the programmer and valve switches are disconnected and there is no switched live going to the boiler.

Is this likely to be a dodgy Aquastat? Thought I check here first.

Any help keeping it going until next year when we plan to get a new combi system fitted would be much appreciated.

Cheers
Mike

 

[king of pipes]

Get the 3way valve checked out by a electrician . cheers kop.

 

[Mikey21]

Get the 3way valve checked out by a electrician . cheers kop.

Yeah, going to get someone to have a look. Wired in a new 3 way valve and it didn't make a difference.

Just one question why would the boiler still fire up if the switched live is completely disconnected?

Cheers
Mike

 

[ShaunCorbs]

Remove the s/l from the heating junction box (12 way) are you getting voltage at the junction box ?

 

[king of pipes]

You can get a back feed through the 3way actuator head a sparky will be able to test this i only do basic stuff but have had alot of problems with 3way valves 9 times out of 10 thats the problem get it tested and the switching on the programmer to best of luck kop