Replacing TRV valve

[Gardener24]

Hi, i have leak coming from trv valve see picture circled. Have had few people come round to fix but either didn't get bk to me or turn up. So I'm thinking is it do able myself? As it's leaking quite bad now and going under floorboards and need this fixing asap. Watched a few videos on YouTube doesn't seem overly complicated to replace just worried about the amount of water that might come out? Any tips on doing it?
Thanks

 

[gas112]

what sort of system do you have . Combi ?

 

[Gardener24]

Yes combi

 

[gas112]

If you release the pressure through a bleed valve be a few pints of water
then you should be able to change it with little to no water coming out , shut the valve off on the other side of rad beforehand

 

[Gardener24]

Thanks for the reply, yes I will do that do I need turn off boiler?

 

[CountryFan]

Thanks for the reply, yes I will do that do I need turn off boiler?

Should be no need to, as when you drain the water it should fault to low water pressure.

 

[endecotp]

You’ve circled the connection between the valve and the pipe. You may not need to replace anything; just dismantle it, clean up, and reassemble carefully with some PTFE tape around the olive.

Personally, unlike @gaz112, I would not try to do it without draining the system to below the level of that radiator. But I’m just an amateur! The pros have some anti-gravity magic that makes the water not fall out.

 

[Harry Bloomfield]

Personally, unlike @gaz112, I would not try to do it without draining the system to below the level of that radiator. But I’m just an amateur! The pros have some anti-gravity magic that makes the water not fall out.

It's called a vacuum - if air cannot get in to replace it, then the water will not leak out.

I would suggest closing both the lock shield valve off, and the TRV - your only possible source of water loss will then be via the disconnected pipe. any accidental flow from that, could then be easily stopped, with your thumb, or more permanently with a cork.

 

[CountryFan]

It's called a vacuum - if air cannot get in to replace it, then the water will not leak out. I would suggest closing both the lock shield valve off, and the TRV.

Exactly. Easiest way to describe it is a thumb over a straw and when you release your thumb (air enters and gravity does the rest)

 

[Gardener24]

The radiator is now off the wall and both sides are supposedly closed but the trv still has water coming out of it when hot water is turned on (faulty valve?) and boiler also sounds like alot of air in it do I need add pressure?

 

[CountryFan]

The radiator is now off the wall and both sides are supposedly closed but the trv still has water coming out of it when hot water is turned on (faulty valve?) and boiler also sounds like alot of air in it do I need add pressure?

Ok, for now, turn the boiler off then. Hot water on? - definitely a combi?

 

[endecotp]

The radiator is now off the wall

Why have you taken the radiator off the wall?

and both sides are supposedly closed but the trv still has water coming out of it

You’d expect that, right? Based on where the leak is, between the pipe and the valve.

boiler also sounds like alot of air in it do I need add pressure?

If it’s basically working now, wait until you’ve fixed the leak and then worry about repressurising.

 

[terryplumb]

Is it the old TRV that is passing water when off ?

 

[Gardener24]

Yep definitely a combi valiant 1 year old. Radiator is off wall to redecorate but seeing as its causing so much problems it will be going straight bk on. Looks like il be getting a plumber out for this one. Thanks for the replies