Can't shut off TRV - even with plastic cap

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I took off bedroom radiator to decorate - was rewarded by lots of water coming out of TRV, so had no alternative but to work quickly and get the pipe ends capped off as quickly as possible.

I then forgot all about it until today, when I finally got around to thinking about putting the radiator back on. Of course, as soon as I loosen the pipe cap, I get water gushing out exactly as before (only this time it's messing up my newly painted walls so I'm even less relaxed about it).

The TRV is a Pegler Terrier, and only about 5 years old, so I'd hope its working fine. The valve settings go down to "0" which I understand is supposed to be fully closed.

I've tried swapping the TRV head with one from another radiator, I've also tried replacing the TRV head with a plastic decorators cap. None appear to push down the valve fully.

I can't think of any alternative now to draining down the system to get my radiator back on. Or am I missing something?

Should I assume the TRV is bust? I've heard of valves being stuck closed, but I would have thought stuck open is less likely? If if try pushing down the valve top with my thumb, I can feel it moving, so doesn't seem to be stuck.

Baffled.
:confused:
 
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I've replaced many TRV and MRV for passing before, it does happen unfortunately! Could bung the system if it's open or just drain pressure out if it's sealed. Don't always need a complete drain for one small item on a system.
 
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Could bung the system if it's open or just drain pressure out if it's sealed. Don't always need a complete drain for one small item on a system.

It's an open system, but what do you mean by "bung the system"?

The radiator is on first floor, so I'm guessing I will need to drain down to below this level.
 
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Bung in the cold feed, bung on the open vent pipe (over the top of the header tank). Let a bit of water out and it will stop like a sealed system. Change the valve then take the bungs out. Don't do it if you have a primatic cylinder (unlikely) unless you want it to implode ;).
 
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Bung in the cold feed, bung on the open vent pipe (over the top of the header tank). Let a bit of water out and it will stop like a sealed system. Change the valve then take the bungs out. Don't do it if you have a primatic cylinder (unlikely) unless you want it to implode ;).

Ah. :idea: So you're talking about the pipes going in and out of the small tank up in my loft? Sounds like a good idea. Do I need to find a well fitting cork (unlikely) or is it going to be easy to lash a temporary bung up from some plumbers putty and a piece of sticky backed plastic?

(Sorry, I seem to have gone all Blue Peter).
 
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Yep, those pipes.

Rubber bungs from a plumbers merchant will be best! I wouldn't risk a bodge tool or you might get VERY wet :eek:.
 
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Yep, those pipes.

Rubber bungs from a plumbers merchant will be best! I wouldn't risk a bodge tool or you might get VERY wet :eek:.

OK, ta. I'll give it a go. (It occurs to me that I have some rubber bungs from my winemaking days ... if I'm really lucky, they might just fit).
 
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Problem is now resolved. I didn't go for bungs in the end as it finally dawned on me that I really should also be replacing the TRV (as it looked to be faulty) rather than just getting the radiator back in place. Drained below the radiator before carrying out the work then carried out the necessary.

Thanks for advice though - will definitely keep the "bung" option in mind for next time around.

:)
 
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