New pressure reducing valve

[Fallout]

Anyone fit a new pressure reducing valve and the pressure just constantly rises

 

[Fallout]

It will lower the pressure when in use but after using an appliance then pressure dial just keeps rising. So can't set to 3 bar.

 

[Fallout]

That's the valve. Pressure just carries on rising to maximum

 

[Johntheo5]

Can you just get a very small flow from it and see what pressure does it then show. What pressure is set to. (looks like 3.0bar)

Also the Predator is NOT a drop tight PRV which means the pressure will rise to the full upstream pressure with no demand.

Drop Tight PRVs (there are probably more)

Caleffi 535

Reliance 312 Series

Honeywell D05

Honeywell D06

NON Drop Tight PRVs

Caleffi 533

Reliance Predator (PRED800015)

Honeywell D04

 

[Fallout]

Thanks so this pressure reducer don't protect the house from high mains pressure when no appliances are getting used? It will just let the pressure get to the pressure would be anyway without a pressure reducer fitted?

 

[Johntheo5]

Yes, that's correct, you must install the drop tight type to achieve no flow set point pressure.

 

[Fallout]

Thanks I've just looked online and it suggests the predator is of the drop tight kind. I've fit one before to protect a water heater from 7 bar pressure and it held at 3 bar.

 

[Fallout]

https://www.reliancevalves.com/sites/rv/files/2022-06/Reliance%20Valves%20Predator%20Pressure%20Reducing%20Valves%20Data%20Sheet.pdf

 

[Fallout]

https://dam.cityplumbing.co.uk/private/xlm4py8/GPID_1009953261_TECH_00.pdf

 

[Johntheo5]

Yes, it does show it as drop tight. Can you check the actual model number, the one I have in my file as being non drop tight is (Reliance Predator) (PRED800015).
Can you remove the down stream pipe and then see if it holds its pressure, if it doesn't then I would contact Reliance for confirmation that it is drop tight and maybe get a replacement one FOC since its obviously faulty?.

 

[Fallout]

Yes it's a Reliance Predator (Pred800015). It doesn't slowly creep to mains pressure it just goes straight to mains pressure when not in use. I'm sure I have fit one of these before to take a 7bar supply down to 3 bar and it held at 3 bar when not in use.

 

[Johntheo5]

Well, must be faulty then, a bit surprising though, maybe worth looking to see if there's any crap under the valve seat.

 

[Fallout]

It must be faulty. If it is genuinely a drop tight one. It says so on the online literature. I think it's serviceable i.e can replace the valve head instead of the whole body?

 

[Fallout]

Even if there not drop tight ones do they only slowly creep to mains pressure?

 

[Johntheo5]

Yes, I wouldn't expect them to just shoot up instantly, what I would suggest is to crack open a tap somewhere just enough to reduce/maintain the setpoint and measure the flowrate.