For some reason unknown to me, our house has two incoming rising mains, bot h with internal stopcocks rising up from the solid floor.
Our combi boiler is attached to one source, as are the majority of our cold water taps, and the other main supplies a handful of other cold outlets.
Local pressure is reasonably high (around 5bar I think) so both rising main s have PRVs attached.
The PRV attached to the "cold water only" main was installed to allow the t hermostatic mixing bar shower to regulate the temperature properly, as it s eemed that the pressure of the cold supply was overwhelming the hot.
Over the last few weeks I've been unable to control the temperature of the mixer shower, such that it is always at a temperature just below ideal - no matter what I do to the temperature adjustment (including removing the hea d and adjusting it) it comes out at the same temperature. To make my showe rs more enjoyable I have taken to leaving a cold tap running (supplied from the same main as the cold feeding the shower), which works (just) and rais es the temperature to a reasonable one.
At the weekend I thought I'd see if I could make some fine adjustments to t he PRV to resolve this.
It is a bog standard COMAP device (same as
I presume that the adjustment that I should do is to twist the screw in the top? However, doing this appears to have no impact on the gauge reading.
I was wondering if the PRV had failed, but it occured to me this morning (w hen the shower I had was nearly freezing because I clearly had had some "im pact"!) that waiting for the pressure gauge to move whilst there was no col d water flow taking place was probably misguided.
Is this the case - do you "set" the pressure on a PRV only whilst the water is in flow (and if so, how much flow? Full taps open, or would less than this suffice?) And am I barking up the wrong tree trying to adjust the pre ssure on the cold side to have an impact on the shower temp?
(Sorry, this seems like a very long post for such a simple question!)
Cheers!
Matt