All radiators fully on but thermostat is off

Dan_Iggulden

I have noticed over the last week or so that my heating comes on full blast even though the thermostat temperature is hot enough.

We have it srt to come on overnight at 14 degree, but I have found that pretty much from 9pm onwards the heating is on full blast until 1-2am, I cannot turn this off as according to the thermostat the heating isn't even on!

Any reason why this would be happening? I thought it mind me something to do with an auto turn on because of how cold it is at the moment but by about 11pm the house is like a sauna!

It doesn't usually do it in the day, just later at night it seems.

southcoastrgi

what system do you have, combi or boiler/cylinder ?, is the room stat on an outside wall ? is the stat wireless ?

Dan_Iggulden

The boiler is a glow worm 30hxi.
The thermostat unit is a panel with a LCD display in our utility room. I really don't know much about this sort of stuff sorry!

macman

Is the boiler or programmer's frost 'stat kicking in? But that shouldn't normally happen unless the return temp drops to around 5C-fairly unlikely if you've set the system to come on at 14C.
Sounds like the 'stat may be faulty and is not cutting out at the required temp.
Check the local temp near to the 'stat with another thermometer.

Dan_Iggulden

Temperature near the stat is correct as this is in our hallway. Boiler is in the garage which is pretty much the same temp as outside, so didn't know if that was the reason?

penrhyn

Dan_Iggulden wrote: »

The boiler is a glow worm 30hxi.
The thermostat unit is a panel with a LCD display in our utility room. I really don't know much about this sort of stuff sorry!

You have a heat only boiler. I suspect what you are referring to as a thermostat is in fact the programmer. Can you read a make/ model number on it?
Do your radiators have TRVs, knobs with numbers on them on each radiators, and is there a thermosat in the hall?

Dan_Iggulden

It's actually doing it now as well, thermostat is set to 14 and hasn't kicked the heating on, but the heating is on full blast.

Dan_Iggulden

Yes thermostat in the hall. Most of the radiators have knobs with numbers on them, the unit in the utililty is a Fanfoss TP9 controller if that means anything?!

Dan_Iggulden

So for all my previous posts where I have referred to thermostat, I actually mean 'controller' as above

southcoastrgi

you may have just answered the question, boiler in the garage an un-heated space this should have been installed with a frost stat near the boiler, when the temp drops this will kick in & run the heating to protect the boiler, it will over ride the room stat & the programmer, it should have been installed with a pipe stat this would stop the system running for hours trying to heat the garage enough to switch off the frost stat, you will need a plumber or electrician (who knows what they are doing) to fit a pipe stat in conjuction with the frost stat on the return pipe to the boiler.

penrhyn

Interesting, its a programmable thermostat after all with a hot water timer.
Here is the manual, might well be worth a study.
http://danfoss-randall.co.uk/PCMPDF/6578_2.pdf

i suspect that the thermostat in the hall may not be connected to anything.
If a room is too hot turn the dial on the TRV to a lower setting.