Replace rad valve without draining down?

[Hubcap]

I'm wondering if there is a clever way of replacing a stuck trv valve (tried hammer, but no better) without draining down my system which has just been filled with Fernox Protector. It's a ground floor kitchen with tiled floor and only 6 inches of accessible pipe above the floor. Boiler is in utility room next to the kitchen. It's a big system with 20 rads over 3 floors. Ground floor is on a separate zone.

I'm assuming that freezing will not work so close to the valve and with Protector in the system. Am I right?

By the way, it's a weird TRV - when you take the head off, the sprung pin in the valve body pulls inwards to close the valve, rather than pushes outwards against the head mechanism. I've not seen that before. I'll replace it with a normal one I think.

Many thanks in anticipation

Hubcap

 

[SimonG]

open vented or sealed?

 

[tipintim]

Is it a sealed system or vented.
If vented, bung off the cold feed and vent an replace
If sealed, release the presure to 0 bar and replace

 

[mountainman]

Easy either way, open vented just takes a little more bottle...

 

[secret squirrel]

Easy either way, open vented just takes a little more bottle...

IMO a lot more bottle, cream carpets, sends shivers along my spine, drain down every time for me, yeah, I'm too chicken.

 

[PlumbBobBob]

hubcap do you know what sort of system you have? is it a combi boiler or a normal one with tanks in the loft?

 

[AlexGas]

I'd say, you should be able to freeze it. An electric pipe freezer will give you more time and space to work - £30 ish to hire.

 

[Hubcap]

open vented or sealed?

Open vented, Conventional boiler, not combi.

 

[SimonJohns]

IMO It doesnt matter what system it is. If someone has buried a AAV in the house. You'll get wet and can be a pain. Takes a bit of experience to do a live valve change.

But. When it's open vented. I;
Isolate rad
Loosen valve. Rad connection not pipe
Drain rad in to dish/bowl
Hold vale in hand. Remove nut on pipe and rad
Change QUICKLY
Reconnect ad fill
Job done

 

[Billy Bob Bob]

IMO It doesnt matter what system it is. If someone has buried a AAV in the house. You'll get wet and can be a pain. Takes a bit of experience to do a live valve change.

But. When it's open vented. I;
Isolate rad
Loosen valve. Rad connection not pipe
Drain rad in to dish/bowl
Hold vale in hand. Remove nut on pipe and rad
Change QUICKLY
Reconnect ad fill
Job done

that tends to work but you still get wet the joys of plumbing