My apologies for a long initial post...
We have always had a problem with high mains pressure. A particular bugbear is an 8 bar CWS relief valve into an unvented Megaflo that lets by regularly. It happens every other day since its' replacement with an 8 bar relief valve by a G3 certified plumber last week - he'd tried a 6 bar one that failed within the week around Christmas. He said that if this was still a problem then a PRV should be fitted to the tank and bathroom CWS. This has been done (I'd had one before but not liked the noise) by me and the running pressure has been set to 3 bar which is great for the bathroom taps. However, and this is my question, when a downstream tap is shut off, the pressure gauge on the PRV - which reads the outlet pressure - winds slowly up to 7 bar and beyond - extrapolation suggests 9 bar or more. I had assumed that the PRV would shut off once the set pressure (in this instance 3 bar) was exceeded. Does this mean that it is faulty, or is there another way of dealing with high static pressure in a domestic CW system? I'm just a bit fed up with constant dripping from the pressure relief pipe and it freezing up in winter - then backs up to the tundish and all the fun that flows from that. I also know that May Gurney's fitters had an awful time fitting water meters with the high mains pressure round here with sudden floods and small lakes in the roads in the last year. On the positive side the showers are wonderful and the bath fills in no time at all!
Before you suggest it, I have regularly reformed the bubble in the Megaflo as advised by Heatrae Sadia. The plumber said it was definitely the CW inlet valve that was at fault.
We have always had a problem with high mains pressure. A particular bugbear is an 8 bar CWS relief valve into an unvented Megaflo that lets by regularly. It happens every other day since its' replacement with an 8 bar relief valve by a G3 certified plumber last week - he'd tried a 6 bar one that failed within the week around Christmas. He said that if this was still a problem then a PRV should be fitted to the tank and bathroom CWS. This has been done (I'd had one before but not liked the noise) by me and the running pressure has been set to 3 bar which is great for the bathroom taps. However, and this is my question, when a downstream tap is shut off, the pressure gauge on the PRV - which reads the outlet pressure - winds slowly up to 7 bar and beyond - extrapolation suggests 9 bar or more. I had assumed that the PRV would shut off once the set pressure (in this instance 3 bar) was exceeded. Does this mean that it is faulty, or is there another way of dealing with high static pressure in a domestic CW system? I'm just a bit fed up with constant dripping from the pressure relief pipe and it freezing up in winter - then backs up to the tundish and all the fun that flows from that. I also know that May Gurney's fitters had an awful time fitting water meters with the high mains pressure round here with sudden floods and small lakes in the roads in the last year. On the positive side the showers are wonderful and the bath fills in no time at all!
Before you suggest it, I have regularly reformed the bubble in the Megaflo as advised by Heatrae Sadia. The plumber said it was definitely the CW inlet valve that was at fault.