Changing Valves

[Ian14]

Hello, I have been doing some work for my son,re-newing his ensuite shower room and now I need to change the radiator valves.
My question for the experts is, do I need to drain down,either part or fully drained, or can I use a 'bung kit' (expanding screw type )
Whichever you advise, what are the points I need to be aware of?

Thanks, Ian (old codger,70,who should know better than to get involved in this! )

 

[manx12]

using the bung technique is alot quicker and less change of airlocks in the coil in the cylinder...
just remember to bung the vent pipe and the outlet for the water supply in the small F & E Tank (inside near the bottom).
also check all Automatic air vents are closed.
make sure both rad valves in the ensuite are turned off.
remove rad
then open one of the rad valves slowly (remember one side at a time)... about a jug and half of water should come out till the vacumn is created in the pipework.. if it continues then you will have to drain down....
once you have changed the first valve.. make sure the valve is in the closed positon. then start on the other valve..
once again when 2nd valve is changed close the valve.. hook up radiator and take out your bungs. up valves check for leaks... good luck..

 

[doitmyself]

The Bung technique is fine, provided your F/E tank is no more than nine metres (30ft) above the lowest point in the system.

An easier way of creating the vacuum - less chance of ruining the carpet with spilt dirty water, is to use the bleed screw in the rad you want to remove.

Bung the vent and feed pipes in the F/E tank
Shut any air vents
Open the bleed valve and collect water in a container until the water stops flowing - a minute or two. If it does not stop the bungs are not making a proper seal.
Close the bleed valve.
Shut both rad valves.
Undo one rad connection collecting any water which escapes in a suitable container.
Remove rad valve and fit new one.
Shut the valve.
Do the other valve.

 

[Ian14]

Thanks for the advice. I hope to do the job on Friday and will let you know how it goes, the rad is already removed as I had to re-position the pipes on an adjacent wall to fit a tall towel radiator.
cheers, Ian.

 

[NickH]

Always remember to shut off the boiler before you start.

 

[Ian14]

Thanks to all of you for the help with this. Did the job on Monday in the end. The bungs worked perfectly. Had a bit of a problem at first as I couldn't find the vent pipe (found it going into the cold water tank eventually) When I connected the new 1.5 m. towel rad. had a small leak from one of the tails, which surprised me as I had used lots of PTFE tape when I put them in. all seems well now though, so ready for the next job - putting in the new floor and fitting the toilet and wash bowl, then there's only the shower door and I'm out of work till they find me something else to do !
Thanks again, Ian.