I have just moved house and found that 3 upstairs radiators do not get hot at all (all the dwonstairs radiators and 3 other upstairs ones work fine). The property has been empty for 3 months before I moved in. I have opened both the wheelhead and lockshield valves. I have tried bleeding the ones that do not work a few times without success. I even switched off all the radiators in the house except the faulty ones and bleeded them while the heating is on and that did not work.
The radiators that do not work all have one side of the pipe hot and the other cold. The bedroom radiator gets a little bit warm and the water feeding pipe is hot (the return pipe is very cold). The other 2 radiators are separated by a wall and the pipes that stay cold are the feeding pipe on one radiator and the return pipe on the other.
Does it mean that the valves just need cleaning or replacing, or is more serious than that (draining the whole system)?
Tried bleeding radiators without success ?
no water, no air or just meaning still no heat ?
It seems like the water is not returning effectively back to the boiler (it is returning slightly otherwise the radiator wouldn't heat at all as the water couldn't circulate) could be an ailock or blockage. Could be a problem with sludge.
I'd suggest getting an engineer ut - as you don't seem keen on draining the system yourself.
Thank you for your replies. The radiators do not have thermostatic valves and they are definitely open on both ends. When I bleeded the 3 faulty radiators, water was coming out all the time. I called someone and he suggested draining the 3 faulty radiators. With the central heating and hot water off, I drained all 3 (one bucket of water for each radiator) one at a time. After switching on the system, the 3 faulty radiators still did not work.