Taking a radiator off with a trv

[Ratman71]

Hi there plumbing people.
I have a question for you.
I have removed a radiator for decorating and it has a TRV. I will not be doing the wallpapering for a few days yet as I needed to strip wallpaper and make the wall good.I won't be having any heating on at all for a while just hot water for Bath ,washing ect.I have not capped the radiator as I thought that if there is no heating and won't be till I replace the radiator that this will be ok. Can you please confirm that this will be ok.if not and you think I need to cap it off why will I need to.I sort of know what a TRV does but thought if no heating could get to it it would be fine.
Thanks for your time.

 

[ChrisOxford]

It should be OK, but you can't be too careful with this kind of thing. If the room temp goes down and the TRV decides to open, you'll have a flood, whether or not the heating's actually switched on.

When you buy a new TRV, they usually come with a special cap which you can install instead of the thermostatic head, to make sure they're turned hard off.

If I were you, I'd cap it off somehow, just to be on the safe side, along with the other (lockshield valve) side. Belt and braces as they say.

At the very least, make sure the thermostatic head is properly attached, and turned right down to 0, not just the frost (*) setting.

 

[Ratman71]

Thank you for the reply.
The TRV was there when I bought the house and as it is a Sunday and nearly 7pm I can't get any thing to cap it off.but you did say it should be ok so I will have my fingers crossed.
I sort of know what you are saying but I still don't really understand how the TRV can still open when I have turned it off by twisting down and the heating is off.I know the air temperature has something to do with it but surely when the head of the TRV has closed how can it open when no heat is affecting it and the TRV is screwed down in the closed position.
I would love to understand this as I have a few more TRV radiators that maybe I will have to take off In the future when It is winter and need heating.thank you for your reply.

 

[cumbriahandyman]

Thank you for the reply.
The TRV was there when I bought the house and as it is a Sunday and nearly 7pm I can't get any thing to cap it off.but you did say it should be ok so I will have my fingers crossed.
I sort of know what you are saying but I still don't really understand how the TRV can still open when I have turned it off by twisting down and the heating is off.I know the air temperature has something to do with it but surely when the head of the TRV has closed how can it open when no heat is affecting it and the TRV is screwed down in the closed position.
I would love to understand this as I have a few more TRV radiators that maybe I will have to take off In the future when It is winter and need heating.thank you for your reply.

I believe the TRV uses room temperature to function. But doubt the temp will drop low enough at this time of year to open even turned down to *

 

[ChrisOxford]

Ignore this post

 

[ChrisOxford]

If the TRV is working properly, you'll be fine. Problems could occur if it's faulty... very unlikely, but not impossible.

Just because the heating's off doesn't mean there's no risk. There's still water in the pipes under some pressure, even if it's not being pumped around.

If all your TRVs are the same make, buy one more as a spare, and it should come with the "cap" I mentioned, which temporarily replaces the thermostatic head, basically just pushing the valve's operating pin as far as it will go, and reliably shutting off the valve.

See section 7 here: //www.diynot.com/forums/viewtopic.php?t=175736

Good luck

 

[ted1234]

If you do get the plastic cap, dont just take off the trv head to put the cap on or you will get wet
The plastic cap needs to be put on before you remove the radiator.
The frost protection would kick in if the temperature drops, but (hopefully) unlikely at this time of year, or as others have said if the valve was faulty.
Ted

 

[Ratman71]

Thank you all for your advice.let's hope I don't need a swimming hat.
Well if I do at least I have a year to practice a stroke and maybe bring a medal back home for us.