Recent content by diy mad

Many thanks for all your help

It’s the EV, not the PRV that is on the cold supply near the boiler Johntheo. The PRV is on the cold water main as it enters the house.

Thanks for all your advice Johntheo Just one final thing, the ev is placed on the COLD water supply to the boiler, that’s correct isn’t it?

What does drop-tight mean exactly? What I can’t understand is that the pressure increase happens immediately the hot is switched off, I don’t think the problem can be related to hot water expansion. Also, just noticed that the increase in pressure is different for the upstairs and downstairs taps!!

It’s a D04 FM from Screwfix

Ah, primary heater exchange?

This is the PRV

The PRV is a Honeywell. Sorry to be thick but what does PHE stand for?

Yes Johntheo, in fact while the hot tap is switched on it drops below 3.5bar but shoots up to 6.5 as soon as it is shut off.

Thanks dal5band, but at the end of the day, when the hot supply is turned off the pressure still reads 6.5 bar, which is worrying to say the least.

Thanks Johntheo but the boiler is supplied by water that has passed through the PRV. Am I missing your point?

Yes, it's a real puzzler. Even if the PRV wasn't drop-tight I still don't understand why the hot tap off gives 6bar and the cold tap off gives 3.

Correct Johntheo, the PRV supplies all cold supply. If I turn on hot tap and off immediately, before any water has chance to heat up, pressure rises to 6bar. If I then turn cold tap on and off it will drop to 3.5,

The boiler is in the loft, the PRV is at ground level. There is a 0.16L. mini expansion vessel about a metre on the cold water supply from the boiler.

Hi, I have fitted a water pressure restrictor but am puzzled that when I turn the cold tap on and then off the pressure stabilises at 3.5 bar as expected. However, when I do the same with the hot tap it reads almost 6 bar! I know that hot water expanding will cause the pressure to rise but I...