Boiler bods.... Central heating will not turn off

[Wapping]

Any ideas?

I have a regular gas fired boiler, hot water tank, a central thermostat in the hall and individual thermostats on all the radiators bar the ones in the kitchen and bathroom.

The hot water and central heating are both controlled by a conventional digital control panel, set to turn on and off at predetermined times. This is showing the heating at 01:15 as being very firmly OFF. All its lights are out and I can advance it to turn 'on' and then 'off' again, so that appears to be OK. The regular hot water system seems fine.

So, the heating is most definitely, 'off'. But, the radiators are still chucking out heat. Even turning the radiator in the sitting room down to zero, has no effect at all. It is still hotter than hell.

The central heating pump in the airing cupboard is pumping away and is now so hot it burnt my hand.

The thermostat in the hall 'clicks' so it appears to work, 'clicking' on and off. It is currently down at 5 degrees but my flat is like the tropics..... on a very hot day. i have tried re-setting it all, with no luck.

It's as if a valve has jammed open, tricking the central heating to keeping running, completely irrespective of the timer and all the various thermostats; the whole central heating system now struggling to dissipate the heat. In short, it appears to be impossible to turn the central heating off.

Any ideas?

Richard

 

[Fanum]

I'll get this one.....I'm pretty damn nifty on heating systems. A valve has jammed open, tricking the central heating to keeping running, completely irrespective of the timer and all the various thermostats; the whole system is now struggling to dissipate the heat.

Glad to help Richard

 

[Wapping]

As am I.

Hotter than July, as the song goes.

Now, how do I find and fix the valve?

 

[columbus]

Sounds the same as ours a while back and it was a valve that wouldnt close. The pump that is running should have a power supply feed somewhere nearby. I switched it on/off a few times which in turn caused the water to shock the valve into closing, or it may have been a fluke. In the end the valve needed replaced.

 

[Wapping]

Sound the same as ours a while back and it was a valve that wouldnt close. the pump that is running should have a power supply feed somewhere nearby. I switched it on/off a few times which in turn caused the water to shock the valve into closing, or it may hav ebeen a fluke. in the end the valve needed replaced

The man is a genius £12 of value in under 15 minutes from UKGSer.

On and off once.... Pump running like a basted.

On and off again.... Pump running like a basted.

On and off again..... Pump has stopped, phew. Two minutes and I can feel the temperature dropping like a stone.

Now, I know I don't want to be getting up too often to perform the on-off trick and I am not entirely convinced I can employ a local wallah or even little Mr Gupta to sit in the airing cupboard, though it will feel like home, I'm sure.

So, now (or rather in the morning) how to track down where the recalcitrant valve lives and (more importantly) how to replace it.

I assume the valve hides in the Grundfoss pump? How the feck does one get it out and what's it called when I go to buy a new one? A valvethingy, I guess; though that does not seem technical enough. Time for an internet search........ Let's see.... Old boilers..... Oh my God.....

 

[Fanum]

Sounds the same as ours a while back and it was a valve that wouldnt close. The pump that is running should have a power supply feed somewhere nearby. I switched it on/off a few times which in turn caused the water to shock the valve into closing, or it may have been a fluke. In the end the valve needed replaced.

Turn the boiler off at the mains.....it will turn itself off and you can go to your bed, then call a man out tomorrow

You probably have a service contract?

Edit...I see it's righted itself....now go to bed, or you'll be all dishevelled in the morning

 

[columbus]

Glad to be of help.

Time for me to go to bed now.

 

[Beano]

Just reading the thread and you say all the heating is off?

If that is the case and both the heating and the hot water are off on the control unit? it is probably the frost stat failed! This stat should be near your boiler if it is mounted in your garage or in a place where it could freeze.

 

[jonnie comet]

Lots of assuming and guesswork here, sssssssssso......

Assuming the central heating valve is sticking. You are likely to find it down stream of the Grundfos pump.....should be an arrow on the pump showing the direction of flow.

You will probably see two valves (heating & hot water) they will look like rectangular, palm sized boxes sat on top of the pipework. You should see a little ‘trigger’ on the side of the valves. Give the trigger a couple of pulls, it might just free the valve off. Long term it’s a replacement jobby.

If the boiler is fitted in a cold place, then it could be the frost ‘stat, but they rarely fail.

.......

 

[spm0912]

Jonnycomet +1

Exact same happened to me a couple of months ago. HW control valve was stuck. General opinion is once they've stuck once!!!!!! You'll need a replacement. Good news is valve was only about 40 quid and depending on where it is shouldn't take too long to fix. I paid £120 inc parts

 

[Wapping]

Thanks a lot chaps for all your help. I found the valve and found the trigger.

I have now got it all limping along but realise that that a new valve is needed.

I have the boiler whatsit insurance, so a call to the bods is on the cards as soon as they wake up.

Once again, thank you to everyone for their help and assistance.

Richard

 

[Blackal]

I would question whether it was a valve.

The position-feedback signal from each zone valve is only the final switch in the path to fire the boiler (normally).

I would say there is a thermostat stuck somewhere.

Room-stat

Tank-stat

Frost-stat (which overrides everything).

Al