One Cold Radiator, TRV pin okay, no air in it. Help!?
If the pipe below the TVR is hot and you are confident the TVR and pin are ok, check the valve at the opposite end of the radiator. People often overlook that, but if water is unable to leave the radiator via that valve hot water isn’t able to circulate through it, having the same effect as turning the TVR down or off…good luck!
Hot water will not circulate if the valves are not turned on. Sometimes there is a bad valve installed, Check to see if one of them is not opening properly. You say there is no air in the rad. Is there water in it. Has it ever heated, or is it just this time. There is a lot of black muck builds up in the water over the years, It may need draining and cleaning, but that is for the summer when the heating is off. One thing is certain, there cannot be any circulation in that radiator. If you can take it off, without making too big a mess, do it and replace the two valves and clean out the radiator.
You have an air lock in the pipework to the rad. That is why the pipe is cold near the valve.It can be sorted, but it can be a wet messy job. First, you have to turn off both rad valves, then drain the water out of the rad. if you do not have a drain off on the rad, then you have to loosen a joint on the rad valve to let the water trickle into a bowl. Open the air vent to let the water run faster, and close the vent to stop the water. When you have drained the rad, then try to move the rad valve away fro the rad so theat it can be run into a bowl. Open the rad valve which has the cold pipe, and let the water run into the bowl until the water is hot. Then close the valve and reconnect it to the rad. Then open the valve and refill the rad. once the water stopds filling. open the air vent to let air out. Then open the other vlve and switch on boiler. Make sure you check the water pressure on the boiler as you are draining the water out, and after venting the air. Good luck.
