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😀

 

[AlexGas]

It's deffinately a good fun. Had to cut the olive too with one finger on the pipe - wrong thread.

 

[Billy Bob Bob]

It's deffinately a good fun. Had to cut the olive too with one finger on the pipe - wrong thread.

yep that can happen though personally i would drain down under those circumstances

 

[AlexGas]

It wouldn't work if you've got a small thumb though! And watch out for the sharp edge!

 

[SimonJohns]

It wouldn't work if you've got a small thumb though! And watch out for the sharp edge!

Especially if it's been cut with a slice and not been reamed

 

[PlumbBobBob]

if you do it live make sure everything you could possibly need is within reach!

 

[SimonJohns]

if you do it live make sure everything you could possibly need is within reach!

Or get an apprentice

 

[SimonG]

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

The only thing I do different is not drain the rad. I have a roasting dish and a few old towels. I'll only drain down if it's 8/10mm and there's a few to do, as the 8 and 10mm threads are always different. Also had some success with a wooden dowel slightly tapered to push inside 15mm pipes, it saves the semi circular chunks of skin coming off your thumb. It gives you something to hold while you slice the old olive.

 

[johnnyplumb]

You can use a small squeeze off tool for this, obviously only for rad tails done in plastic pipe though, works a treat.

 

[Mbear]

I bung open systems all the time if it's possible. Primatic are the exception obviously.
It always usually works unless there is a hidden AAV as someone's already said.

Sometimes I prefer a massive open sys as opposed to a massive sealed sys, bunging the open sys saves alot of time

 

[PlumbBobBob]

i agree i bung every time if i can

 

[Hubcap]

Looks like electric freezer is the way to go. With bungs as back up. Several answers have mentioned AAVs what are they - automatic air valves? And what do I need to look out for? Thank you

 

[pobsdad]

Make sure your phone is close by with a plumber on speed dial,just in case!

 

[Hubcap]

Thanks Pobsdad. If there is a problem, the system will have drained down by the time a plumber gets here though. Any advice on what an AAV is and why I should be concerned would still be welcome though.

 

[Billy Bob Bob]

Thanks Pobsdad. If there is a problem, the system will have drained down by the time a plumber gets here though. Any advice on what an AAV is and why I should be concerned would still be welcome though.

aav }automatic air valve its used for filling and draining a system

 

[PlumbBobBob]

if you have any fitted you have to close them otherwise you wont get a vacuum when you bung the small f&e tank to change the trv.

 

[Best]

Sometimes the bung won't seal off some of the fittings in the expansion tank, - I had to do one last week using a dowel I had tapered off with a knife & some ptfe tape around it.
Often no need to drain rad (do drain it if you find it easier) as I just push a little piece rag in tail. Even if tail is different & has to be changed, I use the rag, change valve first, then have the new tail already done with ptfe & a little paste, & screw new one in, keeping a rag in it too.

 

[Old Account]

Hello all, I have got such job too tomorrow and I would like to ask if I bung those fed tanks off, how can you put them in without sucktion ?

 

[Best]

Hello all, I have got such job too tomorrow and I would like to ask if I bung those fed tanks off, how can you put them in without sucktion ?

Suction?? You just need to put a stopend (push fit) on the heating vent and shove a rubber bung into the fed pipe tank fitting inside the f&e tank. Twist the bung as you push it in. Sometimes it may not seal well. Don't worry about suction because it will hold in place and there will be suction later on it once you take the remaining pressure off the system.
Do make sure all auto vents are closed off, or they will prevent the system being sealed.
Take your time at a handy valve to see if water stops flowing.

 

[Old Account]

Suction?? You just need to put a stopend (push fit) on the heating vent and shove a rubber bung into the fed pipe tank fitting inside the f&e tank. Twist the bung as you push it in. Sometimes it may not seal well. Don't worry about suction because it will hold in place and there will be suction later on it once you take the remaining pressure off the system.
Do make sure all auto vents are closed off, or they will prevent the system being sealed.
Take your time at a handy valve to see if water stops flowing.

Thank you buddy I just thought I'll need suction to get those bungs proper into the pipe. I'll take my time I don't rush work don't want to mess about. Appreciate you advise

 

[lame plumber]

ha ha, dont rush, if your happy them bungs wont fall out.... my sphincter always goes tight using them, dont know why, never does it when I freeze pipes with the leccie freezer 🙂

 

[Best]

ha ha, dont rush, if your happy them bungs wont fall out.... my sphincter always goes tight using them, dont know why, never does it when I freeze pipes with the leccie freezer 🙂

You shouldn't use them bungs on your sphincter!

 

[lame plumber]

You shouldn't use them bungs on your sphincter!

*******, beer everywhere now!!!!!!!!!!!!!!!!!!!!!

 

[PlumbBobBob]

one thing, sometimes the tank fitting which you bung has small lugs which won't let the bung seal properly. in these cases I keep some blutac in my bung box which I use inside a latex glove to give a good seal.

 

[lame plumber]

one thing, sometimes the tank fitting which you bung has small lugs which won't let the bung seal properly. in these cases I keep some blutac in my bung box which I use inside a latex glove to give a good seal.

that read really badly first time round................................ spat some more beer over the dog

 

[Best]

I always remember a former member advising a parsnip for bunging tanks.