My kitchen/utility is supposed to be heated by a large (well 1090 x
610mm) double panel radiator. It warms up in the morning when the boiler comes on and gets progressively cooler during the day, regardless of whether the system is calling for heat or not. The kitchen never gets as warm as I'd expect from a radiator this size.
It is the only rad on the system with a TRV. The TRV and the lockshield are are fully open. When it cools down the pipe (microbore) into the wall at the TRV end gets cold but the lockshield end remains hot or warm. My first thought was the TRV was faulty (it might still be) or blocked. I had the system flushed last year, no difference. If I turn the TRV off the rad gets cold so there appears to be some flow through it. The system is not pressurised. The pump is a Grundfos Alpha, which changes speed as demand for heat varies - I don't know if that might be relevant. All the other rads are fine; I had to turn most of them down following recent insullation work but the kitchen problem pre-dates that. As I type this the temp on the pipe going into the lockshield end is
60 degrees C, on the pipe leaving the TRV it is half that, but feels cold. (Got one of those £7.00 MH1 infra red thermometers from eBay mentioned here on Monday - thanks for the tip.)
Any ideas on how to proceed? TIA