I've got a radiator that is not getting hot. It has been bled. Its got a TRV type control which shows a number as it is turned. Removing the TRV revealed a pin, checking a working radiator, this pin is raised and can be pushed down. However on the faulty one, the pin was not raised and removing the black fixing nut, the pin could be pulled out. I would have expected water to come out as I assumed it was the water pressure that kept the pin in the raised position. Is this correct or is there a blockage in the pipes?
David