PRV pipework help | Gaining Plumbing Experience | Plumbers Forums
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Discuss PRV pipework help in the Gaining Plumbing Experience area at Plumbers Forums

I

i-nano

Hi guys
I would like to know if i can run the prv pipework up and then out of the building, thanks.
 
No!!!
 
You can't, but I don't see why not to be honest. I've seen warm front jobs with the PRV terminated into an F&E tank..
 

Really - I don't see why not? No 3 bar's not going to have much problem going up hill!

or

Really - Yes, I have really seen PRV's fitted by warmfront terminated into F&E's sited underneath the boiler in an airing cupboard in the middle of a house. The stupid thing was they had lifted the floors and drilled through the outside wall to bring a 22mm gas in so no idea why they didn't run in the PRV at the same time. I've seen 3 like it. (used to do warmfront work and these were ones we got sent to remedy.)
 
Another option is a pressure relief valve / condensate removal pump... probs more pricey tho, and i think its designed for boiler PRV not one from a unvented cylinder...

What applicance is the PRV from? make & modeL?
 
You can't run uphill with a prv because of freezing
 
Really - I don't see why not? No 3 bar's not going to have much problem going up hill!

or

Really - Yes, I have really seen PRV's fitted by warmfront terminated into F&E's sited underneath the boiler in an airing cupboard in the middle of a house. The stupid thing was they had lifted the floors and drilled through the outside wall to bring a 22mm gas in so no idea why they didn't run in the PRV at the same time. I've seen 3 like it. (used to do warmfront work and these were ones we got sent to remedy.)


Really as in your second statement , nothing surprises me with warmfront tho , i was always under impression that 1 you have to see pipework blowing off ,and has to take easiest exit from building . Cant see building control being happy wioth uphill prv's etc
 
Scenario

Boiler on 7 day programmer.
Boiler comes on. F and r frozen. Expansion vessel broken

Prv goes up hill and because of failed EV the prv is blocked.

Temp shoots up. Pressure goes mental.

That's why a prv should always fall

It's not about the 99% of the time. It's that one day when it needs to be right IMO
 
Scenario

Boiler on 7 day programmer.
Boiler comes on. F and r frozen. Expansion vessel broken

Prv goes up hill and because of failed EV the prv is blocked.

Temp shoots up. Pressure goes mental.

That's why a prv should always fall

This also sounds a good reason not to trust a remote PRV fitted elsewhere in system

( Simple PRV plumbing explanation )
( Hot water into an air filled pipe , That wants to stay that way ! )
(and has some-where safe to go )
 
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Yea, - common sense to have a PRV close as possible to the boiler & not running uphill. What if pipes leaving boiler freeze & PRV is also somewhere else in house? Boiler turns on, heats up & if can't get anywhere to expand, then something fractures.
Worst things I see done is alleged plumbers replacing f & g tanks with an expansion vessel complete with PRV & filling kit, in attics, when they could easily have fitted it all near the boiler or sometimes used system boilers.
Saw one had the discharge from PRV into redundant plasic overflow! Too bad for anyone below if that PRV opened with hot water! Believe it or not, this I am reliably told, was done by a heating & plumbing instructor!
 
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would be interested to see if someone on here can muster up an MI saying prv can go uphill, have always been informed by build control that it must run down ward , must install tundish if can see no discharge point and pipe to increase in size depending on length ,and cage installed outside
 
Another point to watch is linking a prv overflow to plastic. if you consider the likely temperature of the discharge water could be steam like temperatures, then what would that do to plastic?
 
Another point to watch is linking a prv overflow to plastic. if you consider the likely temperature of the discharge water could be steam like temperatures, then what would that do to plastic?

some plastics are rated to handle 100*c temps and can be used for discharge pipework. You normally have to gain building control permission tho to use it.
 

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