Central heating pump runs constantly for hours

asot

Hi,

My central heating pump goes on for hours even after the programmer has been set to off for both hot water and central heating. This issue has been going on for sometime but gradually getting worse (pump runs for longer and longer). The programmer indicates that everything is off but the boiler power light still stays on. To get the pump to stop going I have to turn off the boiler at the mains.

The programmer was recently replaced so I don't think it's that. The motorized valves seem to operate correctly so I don't think it's those either.

The fault finding guide in the boiler manual would suggest there may be a problem with the thermostat control. Does anyone have any ideas if this sounds right or if it is likely to be something else? Is there anything else I should check?

I have spent £100s of pounds every year for the last 3 years fixing the system so any advice to help me save on plumber fees would be greatly appreciated. If it makes any difference the boiler is a Glow worm Energysaver 40 and the pump is one by Potterton.

Canucklehead

Good evening: Have just read out your post to my OH, Corgi Guy ...he says it sounds like the control thermostat is playing up.

HTH

Canucklehead

asot

Canucklehead wrote: »

Good evening: Have just read out your post to my OH, Corgi Guy ...he says it sounds like the control thermostat is playing up.

HTH

Canucklehead

Thanks very much, that's good of you.

One think I forgot to mention is that every so often the problem seems to go away. i.e. it will constantly run for a few days then I will turn the boiler off for a few days then that will fix it - after I turn it back on again it will start working normally for a while before eventually reverting to the problems again. Don't know if that makes any difference.

Canucklehead

Hello again: OH says replace the control stat first and if this doesn't solve the problem you could be looking at a new PCB....can't properly diagnose the problem without actually testing the boiler in this instance.

HTH

Canucklehad

vaio

asot wrote: »

Hi,

My central heating pump goes on for hours even after the programmer has been set to off for both hot water and central heating.......... The programmer was recently replaced so I don't think it's that. The motorized valves seem to operate correctly so I don't think it's those either.........

When I’m fault finding I’m always suspicious of things that have been recently replaced, you sure the programmer is OK?

The old system was for the programmer to control the motorised valves and any open valve fired up the pump and boiler.

withabix

I swear by British Gas central heating cover.

I will probably get flamed for this, but it's worth the money.