In the summer one of my gas CH radiators sprung a small leak. I shut off the water supply, drained the radiator and fixed the leak. I reintroduced the water to the radiator but when I turned the Central Heating on for the winter, this one radiator remains cold.
I have opened the bleeding valve and after about 20 minutes, the radiator gets warm as "new" hot water flows in to it, but it cools down. I've checked the thermostat valve on the radiator and it seems to be working fine. There is no air in the system and the water coming through the radiator is very clear so I doubt there is sludge.
Any ideas anyone?
Thanks,
Stew