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JG123

Plumbers Arms member
Plumber
Gas Engineer
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Boiler capped for faulty expansion vessel, prv and filling loop??
 
Faulty prv that won't open? If so and with the filling loop being faulty (assuming it's pressuring the system) I reckon that's reason enough to cap.
 
If pressure vessel is faulty then the pressure will raise quite quick , the pressure relief won't open creating a dangerous scenario, don't see why filling loop but,,
 
A filling loop can be capped so nothing to do with that it's purely because if the boilers switched on and the vessels faulty it won't cope with the expansion of the water, in turn pushing the pressure up to the dreaded 3 bar and with no working PRV to vent the excess pressure giving a dangerous situation so Yeh CAP
 
Never seen a prv fail to open.

Seen plenty not reseal afterwards.

More clarification needed.
 
Sorry was a quick one there, I done some cp12s at a block 7 in total. All passed. Now another engineer has gone there 2 months later and capped the boiler for this. I now know the prv was opening slightly and leaking outside and the filling loop was stuck open... How this was re-pressurising the system I don't know as I always disconnect the loop and cap!!
 
He should have just disconnected the filling loop anyway. It's a requirement to always disconnect for this kind of scenario. But most just leave it. I think the person who capped it will soon tell them they need a new boiler?
 
Sorry was a quick one there, I done some cp12s at a block 7 in total. All passed. Now another engineer has gone there 2 months later and capped the boiler for this. I now know the prv was opening slightly and leaking outside and the filling loop was stuck open... How this was re-pressurising the system I don't know as I always disconnect the loop and cap!!

Mind u dripping outside although faulty is not a risk if it can be opened manually, I agree with croppie I've never seen one not open in 20 years, ( I know it could be possible though )
 
When doing a cp 12 the boiler rearly gets to max htg temp so not always possible to check expansion unless it rises quick
 
7,13 is more for heat onlys converted to sealed systems. Its an engineers judgement i guess, was he/she ex BG?
 
Never seen a prv fail to open.

Seen plenty not reseal afterwards.

More clarification needed.

This ^

Technically it isn't on the gas side of the boiler too.

But if the prv was capped then boom
 
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Let me get this straight.
Expansion vessel burst or flat, filling loop connected & prp passing?
And for this some muppet capped the boiler?
 
Never seen a prv fail to open.

Seen plenty not reseal afterwards.

More clarification needed.

Had this once on a Worcester 440. When I got the PRV out to replace it is was full of sludge and all other kinds of muck. I'm guessing something has got in there to jam it and not allow it to open.
 
Had this once on a Worcester 440. When I got the PRV out to replace it is was full of sludge and all other kinds of muck. I'm guessing something has got in there to jam it and not allow it to open.

How would carp stop it from lifting? Unless it was on the outlet side.
 
How would carp stop it from lifting? Unless it was on the outlet side.

I carried out my service as usual, checked the PRV and got absolutely nothing from it. I can't think of another explanation as to why it wouldn't discharge but it wouldn't. Replaced it and the new PRV worked fine. Like I said I've only come it across this once, it was the twist operated PRV and regardless of how many times I twisted it or if I twisted it to the open position and held it there no water would leave it. And yes before you ask the boiler was full of water and sitting at 1 bar.
 
I have had an old worcester that had a faulty prv , pressure kept rising was expecting it to discharge and it never did.
First time i have had it replaced it and worked fine so from my experience it does happen .
 
I carried out my service as usual, checked the PRV and got absolutely nothing from it. ...., it was the twist operated PRV and regardless of how many times I twisted it or if I twisted it to the open position

Do you test EVERY prv like this? Brave.
 
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