I've had a radiator installed in my loft as part of a conversion and it's the only radiator in the house which doesn't (yet) have an HR92UK TRV installed. It's got a TRV fitted which is set to 5 (max) yet it never seems to get hot. I can make it warm if I crank up the radiator from the room below to 35 degrees.

My question is, even though my heating is set to constant, will the new radiator never heat up unless one of the HR92UK valves (from another radiator) is sending a signal to the boiler to hear water? I thought as the valve was open, this draw should fire up the heating...?

In summary, would a HR92UK valve on the loft radiator fix this problem?