Mechanical or Electronic Thermostat?

[JK0]

I have a combi boiler here at home. When I moved in, there was no thermostat at all, just the TRV's.

I installed an electronic programmable thermostat from Maplin the first year, but as I have posted elsewhere, I am still not happy with it. The problem is that my house is now so well insulated that it continues to get warmer even when the thermostat has shut off.

This guy has the same trouble with an electronic thermostat he just bought from Amazon:

http://www.amazon.co.uk/review/R3B2V...&store=kitchen

Now, the old mechanical thermostats used to have what was called an 'accelerating resistor' inside them. This provided a small amount of heat inside the thermostat when the boiler was running. This reduced the hysteresis, (the difference between the on and off temperature) and so reduced the effect that I have a problem with.

I will have to chase out the wall to fit a back box to install a mechanical stat, which would make it difficult to go back to the electronic one. Does anyone think it worthwhile?

[mind the gap]

No, it's not worth it. Dispose of the thermostat altogether and just use the TRVs.

[JK0]

No, it's not worth it. Dispose of the thermostat altogether and just use the TRVs.

Thanks MTG. When I just had the TRV's alone, of course the pump in the boiler was churning away all the time the timeswitch was on, and even in 2005 the bills were shocking. That was why I put on the thermostat. Is it standard practice not to have a thermostat when you have TRV's?

[mk1fan]

The reason the house continues to get warmer is because the radiators retain a thermal mass that is then dispersed into the rooms.

Assuming that all the TRVs are working properly and the system is balanced then;

If the whole house is getting warmer then knock the thermostat down half a degree (or smaller if the stat allows once you get near your desired temperature).

If it is just one room that's getting warmer then turn the trv down incrementally until the desired temp is reached.

There's no need to change the stat.

[JK0]

The reason the house continues to get warmer is because the radiators retain a thermal mass that is then dispersed into the rooms.

Assuming that all the TRVs are working properly and the system is balanced then;

If the whole house is getting warmer then knock the thermostat down half a degree (or smaller if the stat allows once you get near your desired temperature).

If it is just one room that's getting warmer then turn the trv down incrementally until the desired temp is reached.

There's no need to change the stat.

Thanks MK1fan. That is very similar to what I do do. At the moment I wait until the boiler has been on 15 mins, and then hold my finger on the sensing bulb of the thermostat so that it shuts off.

[JK0]

Recently I came across this device:

http://chop-cloc.com/

The idea is that it turns off your heating for 45 mins every hour. This is ideal for homes like mine where the room continues to heat up after the thermostat goes off. Unfortunately these are not yet available.

I just had a flash of inspiration though:

I just set my (mechanical) boiler timeswitch to do the same thing. My boiler is usually on from 4pm to 11pm. For the first hour I allowed a half hour on period to warm up the house, and for the last hour, I allow 3/4 of an hour to give a boost overnight.

I'll keep you posted if this does the trick.

[JK0]

Well, it worked very well this evening. No shivering or boiling at all.