Honeywell thermostat problems

Humphrey10

My mum's got a problem with her central heating thermostat - it's acting like the temperature is higher than it actually is.

So to get it to switch the heating on, the dial needs to be turned up to a silly high temperature, it then makes a little 'click', and switches the heating on. It will then heat the house normally, but it won't heat it to the temperature on the dial.
eg. house is at 17°C, turn dial to 20°C nothing happens, have to turn it to 25°C before it clicks and the heating turns on, then it will heat the house to 20°Cish, not 25 like it says on the dial (numbers approximate!).

It's been acting like this since my mum moved in months ago. The thermostat was installed by the previous owner.

Anyone got any ideas what might be wrong? Is it anything we are likely to be able to fix ourselves?

matbe

Sounds like a faulty stat or badly posoitioned is it under a radiator?

If its positioned ok try replacing the thermostat Honeywell are generally very good and last for years.

ic

Have you checked this with another (known accurate) thermometer at the same location as the honeywell thermostat?

Humphrey10

matbe wrote: »

Sounds like a faulty stat or badly posoitioned is it under a radiator?

I think it is positioned OK - it's not near a radiator. it's in the hall.

ic wrote: »

Have you checked this with another (known accurate) thermometer at the same location as the honeywell thermostat?

The thermostat is currently set to 20°C but it is nowhere near that. I have to turn it to 23°C to get it to turn on. It doesn't turn on when set to 22°C - if it was that hot, I would feel like I was going to pass out from the heat, at home I prefer to have mine set below 20 always. Even 20°C I find uncomfortably hot for doing anything other than sitting around in not many clothes.
I am 100% certain that the temperature next to the thermostat is always a lot (at least 5°C) less than the temperature selected on the dial.

pinkteapot

Just one thought in case you're thinking about replacing it - does it matter? If it's reading five degrees under and 25 actually makes it 20, no more gas will be being used than if it was a stat that said the right temperature.

Our thermostat is left on 25 and it's about 17 degrees in here...

I figure it's only a problem if it's out by so much that you can't actually turn it up enough to get the air temperature you want.

Plumbers_Shop_Lee

Can you tell us what model of room stat you have its on a label on the back of the front cover and also what type of heating system you have ie open vent or combi as certain installers insist on using the cheap T6360 range on combis and the upshot is the problem you describe

martynh99

Ours does the same, i took the cover off (beware there are live electrics in there) and one of the securing posts that the actual thermostat dial is held on by was damaged so the thermostat was broken.

Easy way to test for this I found without removing the cover is to turn the dial to a couple of degrees below where you hear the click to say it's active then gently press in the middle of the dial and see if you hear the active click.

Ours is in the hall too where it is quite cold so about to replace with a wireless one and the actual thermostat will be in the lounge.