Leaking /corroded drain off valve

[coliflower88]

The drain off valve at the end of my radiator has unfortuantly started to drip - as you can see from the pic its pretty corroded.

I've never replace one of these before, is it a job i can undertake? e.g. what process is involved in changing one?

Also is there any preference to what type of replacement to use?

http://www.screwfix.com/p/drain-cock-type-a-heavy-pattern-15mm/99939
or
http://www.screwfix.com/p/jg-speedfit-15bdcp-drain-cocks-15mm/12232

Help appreciated thank you!

View media item 86674

 

[Burnerman]

A bit trickier than it looks, this one......the original is an end fed soldered drain down, the ones you have seen are suitable for use in a compression fitting, or soldered coupling.
First, I'd clean the area and remove all the paint with paint stripper.
With the system completely empty I'd desolder the original drain down, prepare the exposed pipe end and solder a short pipe extension on, to receive the new drain down.
You dont want blowtorch heat to disturb the Tee piece alongside though!
If the old fitting comes off clean, it could be possible to fix a straight compression coupler in place......but the surface would need no solder lumps and so on to be watertight.
John

 

[leakydave]

Why not isolate the system, drain down and just fit a new rubber washer to what you already have? A lot quicker and simpler.

 

[HOWEDPLMB]

buy a simular drain cock drain down heating remove spindle with square end also locking nut on end off drain cock. do the same with a new drain cock the new part will screw into old drain cock refill and test or just replace washer

 

[dominoman]

Remove the centre spindle, take it into screwfix and buy a new draincock that has the same size. Then just use that spindle. Much easier than changing the whole valve, and for the sake of a couple of quid much easier than trying to change the washer.

I've done this on several of my drain valves, all in similar condition to yours, and it works perfectly.

 

[coliflower88]

How does the drain cock come off the pipe; do i need to loosen the square nut at the end and then unscrew with a wrench?

We recently had a new boiler fitted and our CH system was drained, cleared and then refilled with an inhibitor - will this be lost if we drain/refill? silly question im sure..

 

[ALCPlumbing]

No it's been soldered in place using a blowtorch. As stated it is easier to just replace the washer inside.

 

[dominoman]

We recently had a new boiler fitted and our CH system was drained, cleared and then refilled with an inhibitor - will this be lost if we drain/refill? silly question im sure..

It's easier if the system is drained - but definitely not necessary. Make sure you have a helper, some old towels and the new part ready. Then unscrew, with your helper sticking his/her finger in the hole.

Once the spindle is loose you will lose water out that side too, but if you do it all quickly you will not lose too much.

Of course, if the area around is cream carpets then different story. You'll need to drain - or do something like use a pipe freezer

 

[gas112]

What sort of system/boiler do you have you may not to have to drain it down