PRV info sought

[JOB6]

What is a PRV, where is it located in a flat and how is it installed?

I think there may backflow from the combi boiler into my hot water supply, the boiler is small in comparison to the outlets it is providing water for and it was hooked up to the old radiators which heated by the old hot water cistern system. The hot water pressure is too high and I don’t know how to decrease it, and will this will help with the backflow problem.

The flat I live in is from the 50s so old pipes etc. and the combi supplies hot water to the kitchen tap, bathroom sink taps, bathtub taps, shower and I also have a washing machine connected. There are so many pipes, earth wires attached to them and I am just trying to figure out if backflow is the issue and the cold water tap in the kitchen is fine.

 

[PrenticeBoyofDerry]

Why do you think you have a back-flow issue? Because the pressure on the central heating circuit is high?

I would first check that the filling loop is not letting water pass, then bleed a radiator to drop pressure. Do this when system is cold and drop to about 1.5 bar.
Then check that it stabilises, it will increase when heating is on but should not get to 3 bar then drop back to 1.5 bar when cold.
The next thing would then be a check on the expansion vessel.