• Welcome to PlumbersForums.net - The international free plumbing advice forum. Professional plumbers sharing advice with fellow plumbers and DIY alike. Register for free today! - Checkout the Plumbing Advice forum and then our Plumbing Videos area which still needs populating.

Discuss Unvented system and expansion tank pressurisation in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

depr11259

Messages
6
I've recently had a prv changed by a British Gas engineer under the homecare contract that I've taken out. The valve had failed and water was pouring out from the overflow pipe.
The valve was replaced without too much issue. However, the red expansion tank above the boiler was NOT re-pressurised after fitting the new valve. The engineer told me that the system would re-pressurise itself when I used the system over the next few days. I've been told by a plumber friend that this is an error and the tank should have been re-pressurised after the prv was changed.
I'd really appreciate some guidance from an expert in this forum in terms of which advice is correct.
 
Last edited:

ShaunCorbs

Staff member
S. Mod
Plumber
Gas Engineer
Messages
29,440
Solutions
1
Is it on the cylinder the valve or below the red expansion tank ?
 

depr11259

Messages
6
Is it on the cylinder the valve or below the red expansion tank ?
The drip (water flow full force) was after the prv that had failed and the drip has now stopped. Following the replacement of the prv, the engineer did NOT re-pressurise the red expansion tank. Is that a mistake, should it have been re-pressurised?
 

ShaunCorbs

Staff member
S. Mod
Plumber
Gas Engineer
Messages
29,440
Solutions
1
Yes he should of or replaced it
 

Ben-gee

Esteemed
Plumber
Messages
2,093
When you say prv do you mean pressure reducing valve or do you mean pressure relief valve?
 

depr11259

Messages
6
Thanks to Scott_d for making me check the colour of the expansion tank. I wrote the message while away from home and from memory. I called the other half to check and the expansion tank is white!
It's located above the hot water cylinder. I don't have a picture of the area at hand. I'll be back home at the weekend and can post a pic then.
In the interim, thank you for all of the replies and assistance so far.
Paul
 

moonlight

Plumber
Gas Engineer
Messages
936
He still should have checked the vessel, re-pressurised or exchange if necessary.
 

SimonG

Esteemed
Plumber
Messages
20,389
That's why I wanted a photo. I would be surprised if the pressure on the vessel wasnt checked whilst the pressure was off. Well that's what I would do.
 

depr11259

Messages
6
It was a BG engineer (Homecare) who called at 4pm on a Friday and he was very eager to get the job done quickly to start the weekend (It was the euros footie weekend). Perhaps that's why the pressure wasn't checked??
 

depr11259

Messages
6
As promised, here's a picture of the installation.
Paul
 

Attachments

    You don't have permission to view attachments. Attachments are hidden.

John.g

Messages
2,486
This is the correct way AFAIK, I have seen these in a few places on the continent with NO expansion vessel, the expansion valve releases the expansion volume each time the cylinder heats up, don't know if this met local regulations or not even though a expansion vessel should not be considered a safety feature as it can fail at any time and fill with water.

You don't have permission to view attachments. Attachments are hidden.
 

Attachments

    You don't have permission to view attachments. Attachments are hidden.

Reply to Unvented system and expansion tank pressurisation in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

Similar threads

N
It won't be your expansion vessel, more than likely the PRV (pressure reducing valve) is passing, these should be "drop tight" can you take a few...
Replies
3
Views
585
John.g
J
H
I depressed the white plastic insert and water squirted out. I was attempting to lower pressure when I first started to work out why I was losing...
Replies
26
Views
630
Hoppers
H
C
Not necessarily, like a car tyre, it could be punctured and needs replacing or the valve might be letting by so it needs pumping up again and the...
Replies
1
Views
494
Marc Bowers
M

Newest Threads (Please Reply)

Search Forum

Top