Changing radiator valves without draining down

[Mikie]

I recently had a leaky TRV changed under a service contract. The engineer did not drain down the heating. Apparently he just plugged the vent pipe and boiler supply pipe in the header tank. Water did not flow out when he removed the old valve because air could not get in, and this was on a downstairs radiator with quite a head of water.
Is this common practice? I need to replace all my other ancient TRVs and hope to use the same technique.

 

[ChrisR]

Try searching on "Bung" "Bunging" etc. Has been discussed many times.

 

[JohnD]

it is common and easy

however if you need to replace several you may as well drain (you will loose water from each rad you work on)

bunging only allows you to open one point at a time.

You can add a chemical cleaner for a week or two before draining, and kill two birds with one stone.

if you have any worn, leaking or jammed bleed valves or lockshields you can change them while you are drained. The parts are very cheap.

 

[zimmers]

Go and get pack of regin rubber bung kit,it is ideal for working on a conventinal system,put onbe over the expansion pipe and one in the header tank,plugging the cold feed,then find trvs that will fit the same nut ,so you can just fit the body,put some ptfe around them and i always run a thin layer of fernox external leak sealer around the olives,i changed 10 on a system yesterday in a hour,then the last one was 8mm,and the reducer set wouldnt let the nut tighten up,so i had to drain down completely and as the 8mm came out the wall,it had no pipe i could play with,so i had to put a bit of 10mm pipe over the 8mm,and solder it ,it was ok,but if id have checked the job first,id have sorted it out.