Towel radiator valves sticking

[GW]

Hi all,
In the bathroom I have a towel radiator like this one (http://www.tradeplumbing.co.uk/product.asp?itemid=68&catid=36). The problem is that one of the valves is very difficult to turn and is effectively jammed - it just about turns one revolution. Therefore, the radiator always stone cold and never comes on even though the other valve can be turned. Do I have to replace the valve completely? I have tried fiddling about with the valve and bleeding the radiator but this hasn't worked. Is it worth getting a plumber to do this, or is it easy to do. I'm not an expert but I guess I would do the following:
1. Shut down boiler.
2. Drain boiler down a bit as the radiator is upstairs.
3. Replace valve (do I need to use PTFE tape around the joints)
4. Refill boiler.
It is point 4 I am worried about. I think I need to use some anti-corrosion fluid but don't know how much or where I would introduce this.

 

[slippyr4]

It's not that hard, but you need to be confident enough to deal with any other problems that may occur.

In a nutshell, your procedure is correct. You need to use 6-8 turns of PTFE on the parts of the new valve where the thread is the seal. This is probably just the taper threaded tail which screws into the rad. Wind PTFE onto the male thread, clockwise as you look at it (as if you were screwing a nut on). Any joints which are compression fitting should not have ptfe. You will need new olives for compression fittings; and this likely means that the existing olive and nut will be stuck on the supply pipe- you'll need to cut the olive off very carefully with a hacksaw.

You should definately add inhibitor. The dose isn't critical, and one pot of sentinel X100 should do the trick.

Instructions for how to refill your system are pretty much impossible to give unless we know whether it's a conventional, sealed, combi etc.

If it's conventional, you add the X100 to the feed and expansion tank in the loft. If it's a sealed system then there are a variiety of ways of adding it. Probably the easiest way would be to buy the inhibitor in one of the super concentrate packs which comes in a caulk tube - like frame sealant - which you can use to inject the fluid through an air bleed valve.

It makes sense to put the inhibitor into a different radiator upstairs, that radiators with its valves turned off. then, you can refill, check for leaks, and when happy open the valves to this last rad and let the inhibitor in. saves wasting it if you have a leak in your work and have to drain down.

good luck

slip