I have a radiator with a Drayton TRV4 Thermostatic Radiator Valve which
had been working perfectly for years. However, the radiator does not
completely go cold anymore, in fact is still quite warm, when the
heating is on in the rest of the house.
I have removed the thermostat head and examined the pin in the valve
below. I can only get a very small movement in the pin even when I have
given it a few lightish taps with a hammer. This amount of movement does
not seem to be anywhere near as much movement as the plunger in the
thermostat head when I wind the control fully in and out on the TRV head.
My question is:
Should there be more movement in the pin on the valve than I am getting ?