steveoelliott

Coming back to my original issue, I even got the noise (previously) with the cold inlet to the Megaflo shut off after a reheat. Now I guess there would be pressure in the small piece of pipe between the cold inlet closed but I would be surprised if this caused the issue. I measured the water temperature at the tap which is some distance from the tank and it measured 57.5 with the tank thermostat set to whisker above 3. I debated dialing the temperature down a little to see if that stops it but one has to be careful of legionnaires. I haven't lowered the EV pressure to 1.8 bar yet, it's something I intend to do when back from a business trip. Playing with it just before I go and leave my wife here isn't something I'm keen on doing as at least I can keep an eye if here. Mind you it was set at 2.8 bar back in January so I suspect it will be decreasing slowly anyway I had wondered if the layout of the pipework from EV may cause issues like this to occur or be worse.

@John Carroll I didn't play with it whilst the gauge was compromised, I will need to do this with a gauge on the outside tap again. @Nickfromwales Not sure if the gauge was pre-installed or my plumber put this on the PRV. I know the new cap thread was put on using liquid PTFE. That said, the leak was definitely internal to the gauge. That green staining behind the O ring was never wet and I suspect it may have been the result of condensation as I've seen it on these pipes before when cold water comes in.

The gauge was removed today by my plumber and capped off. As you can see there was some corrosion internally and I think eventually this may have caused some issues.

Interestingly I got a response from the manufacturer stating that the gauge on the PRV should only be connected when setting the PRV and then capped. They said that constant exposure will inevitably lead to corrosion of the bourdon tube and lead to leaks.

@Alan Ambrose @John Carroll Thanks for the feedback. The valve in this case is just part of the PRV but it can be easily capped off. I noticed this morning that the water has dribbled out the front of the gauge but there doesn't appear to be any new water. Something must have triggered this weep or it could even be condensation. My plumber is supposed to be coming to cap it or swap it.

Thank you. I probably will avoid using gauges permanently for this reason. The outside tap one is a great idea and I hadn’t considered them having a check valve on them.

Thanks. About 10 -12 metres to street. It’s 15mm pipe incoming. When I measured the static pressure at the outside tap, which is the other side of the house that was matching what was on this gauge though. I’ve asked my plumber to replace / cap off that gauge this week. In the interim, I am checking it regularly as I am concerned about it peeing our water everywhere but this is a new and separate issue.

And of course replace the gauge next week @John Carroll. I know previously you’ve said about installing gauges at multiple locations but the risk of this happening to them and potentially leaking is a concern for me.

It happens after a reheat if it’s going to happen, but then doesn’t always. here is a picture of the PRV. I am concerned there is water in a gauge which I’ve just noticed. Good advice re setting the PRV. I will try that.

Outside tap is downstream. Problem is I believe the outside tap has an NRV so you never see a pressure drop. I’ll try and find model of PRV.

Interestingly, I thought of this. I took the pressure from an outside tap or one of those screw on things you get from Amazon that was also 4 bar. PRV main is caleffi and the uvc Baxi.

It reads 4 bar almost immediately after shutting tap off and stays there. Might be a bit more or less depending on time of day etc. it never really creeps up. It is a large 5 bed house with lots of outlets / 4 bathrooms so a big system to flow around.

Thanks. What’s the correct way to set the PRV though. With a tap open? And should I aim for static pressure at 2 bar? I think the issue is the static pressure at 4 bar despite it dropping to 2 bar static when tap open.

Yes the stop cock PRV is on the main and prior to the UVC PRV. It seems to be the rapid discharge from the EV that triggers this.

One at the main and one on UVC. It’s this that gives the balanced cold. They offered a UVC but I took the option of a boiler instead as I planned not to use a megaflo going forward to opt for another cylinder. The thing is I want to be certain it is the cylinder before swapping. Are you able to advise how I set the dynamic pressure on the PRV off the stop cock. Is it just open one outlet and set? The static is around 4 bar and between 1.8 and 2 bar when running. thanks again.