Faulty Thermostat?

[Roandy]

Hi everyone,

I have a central heating system with a Worcester Bosch combi boiler which was installed 15 years ago by British Gas, but on two occasions in the last couple of months the boiler has become unresponsive when I use the thermostat to adjust the room temperature. The thermostat is a British Gas ES1 make which is wired. When I press the save button on the thermostat, the light usually begins to blink and once the temperature has adjusted it will stop blinking, click and the boiler will fire. What has been happening is that the light stops blinking but the boiler doesn't fire. Moving the dial on the thermostat or pressing and repressing the save button doesn't bring any response (which it usually does).

Last night before I went to bed I pressed the save button again and left the thermostat blinking with the boiler off. By morning it had stopped blinking and thankfully the boiler fired when I turned it on, but I was without heat for several hours last night and I'm concerned about using the thermostat in case it happens again. The hot water has been fine, so I was wondering if it is the boiler or simply the thermostat which is faulty?

I probably need to call in a professional, but any advice or suggestions as to what the problem might be would be very much appreciated.

Many thanks

Andy

 

[leesparkykent]

Sounds like the thermostat but the easiest way to confirm this would be to check there is voltage at the terminals when the thermostat is calling for heat. Unfortunately you will need a gas safe registered engineer to do this for you as the boiler casing will need to be removed to do this. Another option would be to pick up a Drayton RTS1 from screwfix for £18 which is a direct replacement and just swap the thermostat over by loosening the two screws on the bottom. If it works happy days you don't have to call a GSR engineer out and if it doesn't you can just take it back to screwfix.

 

[Roandy]

Many thanks Lee. I will call in someone to look at it, rather than attempt anything myself (hopefully it will make it to the end of the month!) Very little has gone wrong with the system in 15 years so I certainly can't complain.

Just to add also it might be better to simply turn the boiler off rather than use the thermostat.

 

[Dotty]

Careful turning the boiler off as it will have pump overrun to protect the heat exchanger from latent heat damage.

Far better to turn the boiler stat down.

 

[Roandy]

Hi again, I just wanted to post an update to say that the new thermostat has now been fitted and everything seems to be OK. It is actually the Drayton RTS2 model rather than the RTS1 and has an led light.

I must say I have been really impressed with it so far, and everything the old British Gas ES1 thermostat did manually, it seems to do automatically. You simply choose a setting you are happy with and leave it to do it's thing. I have a feeling it may even prove to be a bit more energy efficient than the old one and would have been worth the money just for the upgrade.

Thanks again all.