I think my heating controller has packed up .....

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Oxfordshire
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I got nagged this morning about the hot water being tepid.

I have checked the boiler and its off, no power no lights, nothing... Its a Potterton Promax System 24 HE Plus.

The controller (Honeywell ST6400C) is on and set to supply but it seem that the boiler is not seemingly getting any power. I have but a meter across the live supply in to the boiler and nothing.

I don't think my controller is supplying power, I have checked the power across the live feed (marked L) and the grey wire on terminal 3 (I believe this is the HW on signal) and again, nothing.


To bypass the controller and check the boiler is still working, can I short L to terminal 3? I assume that's all the controller does (albeit on a timed basis)

I don't want to spend on a new controller only to find its not the problem...

Any advice or help much appreciated...
 
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Hey Micky, thanks for prompt reply.

Tried that (after changing fuse in spur from 13a to 3 a fuse....) and had no luck.

Still can't get any power at the boiler. :confused:
 
your boiler should have a permanent 240v supply, the timer just supplies a "run" signal to the afore said boiler, there is a fuse in the terminal strip where the permanent live is connected , check the fuse is ok.
 
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your boiler should have a permanent 240v supply, the timer just supplies a "run" signal to the afore said boiler, there is a fuse in the terminal strip where the permanent live is connected , check the fuse is ok.

Right. Many thanks for the tip.

I have found a mystery fused spur at the other end of the house that seems to feed the underfloor heating. Apparently it also powers the boiler... Quite why its done like that I have no idea, but hey ho problem solved....

Ta..
 
Does the motorised valve (probabily in the airing cupboard) operate when the progammer is set to come on? Or when you short out L to 3? If not could be a valve problem, you see the controller supplys power to the valve, which opens. This then operates a switch inside the valve which sends 240v to the boiler to fire. You could try manually operating the valve using the small lever on it and see if the boiler fires then. Chris
 

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