What pressure release valve do I need

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robpoulter

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The old pressure relief valve on my hot water tank has died, finally explaining the freshwater leak.
I bought a 2.5 bar one, as I was in a rush and hadn't checked the pump pressure. Upon fitting it once more pee'd water everywhere.
Subsequent contortions, and a bit of wire wool mean that I now know the pump is rated at 40 psi ( approx 2.8 bar).
Now, finally, the question. How much above this does the pressure release valve need to be?
My chandelry can get a 3 bar one, but this strikes me as being a bit close to 2.8.
What release pressure does the panel suggest, and where can I get one?? (1/2 inch male BSP thread)
Cheers
Rob
 
BES www.bes.co.uk do an adjustable one for £1.15. part no 7512 That might be your answer. Fit it and screw it down 'til it does not leak. They dont say the max pressure though.
 
I've just changed my 3 bar one for a 6 bar one. The old water pump failed and the new one, while nominally rated at 2.8 bar kept on pushing water out into the bilge. My local plumber's merchant then sold me the "next size up" which is doing a sterling job.
I don't know, however, what the pressure rating of modern plastic pipe joins is, so it's possible that one of the joins would be the first thing to go in the event of the pump pressure switch failing /forums/images/graemlins/shocked.gif
 
I think you need to check the make/model of the water heater and find out what pressure the RV was designed to. It is there to protect the water heater from excess pressure and different manufacturers have different design pressures.
 
Purely in case someone searches this I felt I should report back.
Pump rated 2.8 bar, PRV rated 2.5 bar = water hosing out of valve
Pump rated 2.8 bar, PRV rated 3.0 bar = water dribbling out of valve intermittently.

I'm off to look for a 3.5-4 bar valve!!

Rob
 
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