Thermostat and Radiators

MorecambeChris

Recently moved in to a rented property and it is nearly time to put the heating on!! Always had storage heaters before so this is new to me. Does anybody know why I have a thermostat when all the radiators have their own dials with l, ll, lll, llll etc? Do I need to set the thermostat to a particulat temperature and then adjust all the radiators depending how warmer I want the heat?

Pincher

The thermostat is the only thing that is wired into the boiler to switch it on when it's cold.

The TRV on the radiator just restrict hot water flow, so if the boiler is not on, nothing happens.

MorecambeChris

Pincher wrote: »

The thermostat is the only thing that is wired into the boiler to switch it on when it's cold.

The TRV on the radiator just restrict hot water flow, so if the boiler is not on, nothing happens.

Sorry I still do not get it. Isn't the boiler on all summer as how do I get hot water?

Cardew

The boiler will provide Hot water(for Taps etc) and also for CH.

You will have a programmer that allows you to select HW only(for summer) and HW and CH(for winter) This programmer will also allow you to have HW and CH to be timed for the periods you want each day/ or all the time.

When you have the CH on with the timer, the wall thermostat determines the temperature of the room in which that wall thermostat is situated. When it reaches the set temperature it switches off the boiler.

The controls on the radiator are called Thermostatically Controlled Valves(TRV) and these determine the temperature of the room in which the radiator is situated. So you could have, say, 20C set in the living room, 17C in the bedrooms and 22C in the bathroom.

However you must remember that these TRVs will not operate until the wall thermostat is 'calling for heat'.

Pincher

The only thing in the subset of hallway thermostat and TRVs, which were the context universe of your question.

Assuming you have a combi, the hot water flow triggers the boiler.

Alternatively, if you have a hot water cylinder, that has a thermostat wired into the boiler that switches on the boiler.

Hmm, this brings on an interesting design.

If we did not have a hallway thermostat, but every radiator has a TRV, as in your concept of how a central heating system should be, then we can put in a flow activated central heating pump (if there was such a thing). Put in a foot pump on the radiator return. When you want heating, step on the pump a few times, which creates flow, which activates the central heating pump, and the boiler. The boiler will start heating the house up. The TRVs will then close one by one, as the set point is reached for each room, until no flow is possible, which shuts down the pump and boiler.

This design overcomes the inherent problem of a hallway thermostat, which cuts out the boiler when some rooms are still cold. The rooms are heated to the individual temperatures you want, job done.

This design also has the advantage of no need to bury a three core flex from the thermostat to the boiler, which is a major eyesore if you had a surface run.

You are the final arbiter of how hot the rooms should get, a human thermometer.

MorecambeChris

Cardew wrote: »

When you have the CH on with the timer, the wall thermostat determines the temperature of the room in which that wall thermostat is situated. When it reaches the set temperature it switches off the boiler.

Thanks. I think I get it I will just have to test it all soon! My thermostat is not in a room, it is in on the middle my stairs which seems strange (but there is no hallway or landing, it is a 2-bed terrace).