Radiators have different temperature

[MM33]

Hi all,

I recently moved into a new house, I noticed that the radiators run at different temperatures. The boiler is set to 60 degrees, some radiators are very hot to touch, others are extremely mild.
The developpers sent someone to look into it, he throtteled the hottest radiators (missed a couple) now they are all mild. Is this normal ?
In my old house all radiators ran at the same temperature which was controlled by the boiler, the radiators in this new house are as hot as the ones in my old house when I set the boiler to 45 degrees.

 

[oldbuffer]

1. I would guess your radiators have thermostatic radiator valves (TRVs) on them.
2. TRVs sense the temperature in the room, and when it reaches a temperature equivalent to the number set on the TRV head, it starts to shut the radiator down.
3. So if a room has an air temperature equivalent to the TRV setting, that radiator will be shutting down and cooling.
4. Any room where the air temperature hasn't reached that set on its TRV will have the radiator on, and thus it will be hot to the touch, up to the maximum temperature of the boiler water.
5. With a modern condensing boiler, the aim is to get the return temperature at the boiler as low as possible consistent with heating the property. Its normal to aim for a return temperature of 55 degrees, a temperature drop across the system of 20 degrees, and hence a flow temperature of 75 degrees. If you can get the heat you want (i.e. a warm house heated in a reasonable time), then the lower you can set the flow temperature the better.
6. Very broadly, and with no guarantees, 5 on a TRV equates to about 22 degrees, 4 to about 18. If you know the make and model of your TRVs you may be able to look up more accurate figures.