cold bathroom radiator (gravity fed/central heating

[2uselessdiyer]

My radiator has gone cold. I have used a magnet to show where the blockage is (according to some of your info) A plumber removed a valve on the inlet unblocked it and all ok for 2 months. Now back to square 1.No-one in this area knows how to repair it. They also said that sentinel cannot be used because it will come out in the bath water and I will be sitting in a chemical as the radiator heats when the hot water only is on. This sounds daft. Any advice out there?

 

[dcawkwell]

Mains flush the system.

Remove a radiator attach hose pipe to radiator valve.
Attach hose pipe to other end.
Start the mains. You might need to cap a vent pipe if you have a primatic cylinder as I suspect.

Open valves in each radiator in turn to flush each out.
Sorted.
Ensure system is balance once finished.

 

[2uselessdiyer]

I wish that there was a plumber in this area who was as concise as you. Tks for your help, I shall give it to the first plumber who comes in.
I forgot to mention that this is a towel radiator that works when the hot water is on( gravity fed maybe but I think that it is pump fed?).