radiator water temperature?

jannowretired

Never having had gas central heating with radiators in my life, at present I have warm air heating.

Does the temperature of the water circulating round the radiators decrease as the temperature of the house increases or is it always the same temperature?

At present with my warm air heating as the temperature increases the output of the heating unit decreases with the fan slowing down so that eventually there is just enough heat to maintain the temperature.

Cardew

The water temperature in the radiators is set by you on the boiler - it can range from approx. 45C to 80C.


That is the output from the boiler, it drops slightly as the water goes around the radiators.


On the radiators there should be Thermostatic radiator valves(TRV) and these are set by you for the desired room temperature.

Pincher

Twenty yeas ago, there's a knob on the boiler, which sets the temperature of the water coming out. Too hot, and the radiators will scald your children, so you turn it down a bit.


Modern condensing boilers prefer the returning water to be cool, so it can pickup residual heat from the plume (steam) before it goes out the flue (chimney). This means they try not to output water at high temperatures, if there is no need for it. But it takes longer to heat the house up, obviously. There is still a knob, but you should leave it low, and let the computer optimise away, unless you have a good reason.


Note that in order to heat hot water in a cylinder to 65 degrees, the boiler outputs at 80 degrees, ignoring the knob anyway.

jannowretired

The idea is to have a computer in the boiler that turns the flame up and down (aka modulating) according to

From another post.

Does that not imply that the temperature of the water will vary like turning the flame down under a boiling pot of water on a gas cooker?

Or do these type of boiler controls not exist yet?

I was able to control the water temperature when I had radiators with a coal fire.

Consumerist

jannowretired wrote: »

. . . Does the temperature of the water circulating round the radiators decrease as the temperature of the house increases or is it always the same temperature? . . .

In a nutshell -

The water temperature from the boiler is essentially constant but the boiler modulates the gas consumption according to the return temperature. When your main thermostat reaches the set room temperature, the boiler switches off until the thermostat signals that the room temperature has dropped again.