potterton prt2 thermostat not responding to temperature

[MilaGB]

That's unusual, it sounds like the room stat is out of adjustment. It is mechanical so there might be some kind of adjustment inside.

I don't know that model, but the easiest fix would be to fit a new one. There are a number at around £20 or less. Your current one has indicator lights which are quite handy. Yours may have two, three or more wires inside and you can get one with the same. Examples (sort it to "price low to high," though Drayton and Honeywell are quality brands)
https://www.screwfix.com/c/heating-...s/cat831444#category=cat4600002&sort_by=price

There are also programmable stats and smart stats at higher cost. I favour the programmable. The more sophisticated ones are less intuitive and harder to set.

Wireless ones go wrong more often.

Thank you so much! So much useful advice!

 

[MeldrewsMate]

Just checked the dial next to the boiler, it showed 75, I turned it up to 85. But I suspect it's the dial for hot water because the lights aren't on, and hot water heating us turned off at the moment.

May I just establish something, before we go on...
Do you have just ONE room thermostat, and that is the PRT2 that you posted photos of?
Are you confusing the boiler with the hot water cylinder?
The boiler is the thing that burns gas, a backboiler usually has a gas fire on its front. Is it this that you turned up to 85C ??
A hot water cylinder is cylindrical and contains hot water for bathing purposes. A hot water cylinder often has a thermostat attached to its side.

Once these are established we can make progress.

 

[MilaGB]

May I just establish something, before we go on...
Do you have just ONE room thermostat, and that is the PRT2 that you posted photos of?
Are you confusing the boiler with the hot water cylinder?
The boiler is the thing that burns gas, a backboiler usually has a gas fire on its front. Is it this that you turned up to 85C ??
A hot water cylinder is cylindrical and contains hot water for bathing purposes. A hot water cylinder often has a thermostat attached to its side.

Once these are established we can make progress.

There's just one room prt2 thermostat with temperature dial, it's located in the hall.
The thermostat with 75/85 max has ptt2 written on it, it's next to the cylindrical boiler in the airing cupboard.
Thank you for not giving up on this!
I've ordered a replacement thermostat for prt2 but am yet to try and disassemble the current one to see if I can adjust the dial on it. If I manage to do this and it solves the problem?? I'll return the new one.

 

[MeldrewsMate]

The PTT2 is the remote thermostat for the hot water cylinder temperature. It has no bearing on your reported problem, though it is normal to have hot water set at or around 60C.......85C is far too hot.

A back boiler (you have not declared its make and/or model) will have a temperature control knob, called the boilerstat, accessible low down. It is this to which I referred earlier. I suggest you set it at about 3/4 of maximum.

 

[MilaGB]

The PTT2 is the remote thermostat for the hot water cylinder temperature. It has no bearing on your reported problem, though it is normal to have hot water set at or around 60C.......85C is far too hot.

A back boiler (you have not declared its make and/or model) will have a temperature control knob, called the boilerstat, accessible low down. It is this to which I referred earlier. I suggest you set it at about 3/4 of maximum.

I'll change the hot water to 60 tomorrow as I'm in the other room right now.
Will check the back boiler make/model and boilerstat tomorrow too, thank you!

 

[MeldrewsMate]

Your photo in thread number 12 shows that the PRT2 roomstat is set to 30C, and that temperature has been reached. I suggest this is NOT the case!

Perhaps your best course of action is to replace the PRT2 like for like, and the problem will be solved.
If you do get hold of that mutimeter, it'll be interesting to find out the resistance of the sensor from your old PRT2 once its disconnected.

MM