Correct installation of PRV, and requirement for NRV?

[samba1]

Hi Guys,

Dyno have fitted a PRV under the kitchen sink in an attempt to resolve a H/W cylinder popping noise and issues with mixer taps, which unfortunately hasn’t cured the issue. I am concerned with the installation of the PRV (and the removal of the NRV) and would like to hear your comments.

Originally, I believe I had a non-return valve after the internal stopcock, which is shown on the first picture. This has been taken out and a new stopcock and PRV has been fitted, and the second picture shows the current set up. I have 2 questions:

1. Is it the orientation of the PRV correct? I have read the spring bonnet should not face down and the whole valve should be mounted horizontally. My concern is that should gauge (which has a plastic fitment, not brass), or the valve fail, I could end up with a huge leak.

2. Should original the NRV be reinstated? Isn’t this a regulation so that there is no back flow to drinking water supply? I’m guessing it was just an oversight on Dyno’s part but if it’s wrong then I’d like to have the confirmation from you guys to say it ought to be reinstated.

I have suggested that the PRV orientation and NRV perhaps need to be rectified, but I’d like to hear from you guys in case I’m wrong or I get fobbed off they say it’s all fine, etc.

Thanks!

 

[Maryplumb]

Hi Samba
The instructions for the Honeywell D04FM PRV (which looks like the one you have) do state that the spring bonnet should face upwards, but vertical installation is allowed.

http://www.free-instruction-manuals.com/pdf/pa_1194759.pdf

Check valve (non return valve) after main stopcock as you say is a requirement of the water byelaws, and it does look like they have removed it for lack of space on the pipe. You can get confirmation from your local water authority.

But is the cylinder unvented? if so there should be a pressure reducing valve on the inlet to the cylinder, maybe that would be more relevant to the problem.
There should be a connection on it to allow the cold taps to be at the same (reduced) pressure and therefore equal with the hot at mixers. Though there are some situations in which it's not feasible to run the cold pipe from it, maybe that's why they've done it on the incoming main?

 

[samba1]

Hi Samba
The instructions for the Honeywell D04FM PRV (which looks like the one you have) do state that the spring bonnet should face upwards, but vertical installation is allowed.

http://www.free-instruction-manuals.com/pdf/pa_1194759.pdf

Check valve (non return valve) after main stopcock as you say is a requirement of the water byelaws, and it does look like they have removed it for lack of space on the pipe. You can get confirmation from your local water authority.

But is the cylinder unvented? if so there should be a pressure reducing valve on the inlet to the cylinder, maybe that would be more relevant to the problem.
There should be a connection on it to allow the cold taps to be at the same (reduced) pressure and therefore equal with the hot at mixers. Though there are some situations in which it's not feasible to run the cold pipe from it, maybe that's why they've done it on the incoming main?

Thanks, you’re spot on it’s a D04FM. I did read that install manual and it says “- In vertical installation position spring bonnet with adjustment knob facing upwards” which is why I was a little concerned, especially as the gauge has a plastic connector and as the spring bonnet is facing downwards I’m concerned that it could lead to a premature failure.

I’ll check with the local water authority, but given the house builder put it in I’m guessing that it’s a local requirement.

The cylinder is unvented, and yes it has a combination valve. It’s a complete replacement of existing unvented cylinder, EV and combination valve. Balanced cold not possible as it would mean ripping out flooring and making significant changes. I’ve posted very recently on the forums about this saga (still ongoing). I believe I have a faulty unit (both cylinder and combination valve), they’re making massive bangs when hot water is drawn. The combination valve sounds like an aircraft when water flows through it as hot water is drawn from the cylinder, and alarming popping/bangs coming from (I believe) both the cylinder and combination valve during hot water being drawn. It’s like someone taking a hammer and smacking the cylinder. Dyno are confused, as the old unvented cylinder, EV and valves where totally silent. They’ve contacted Gledhill and I feel I’ve received a reworked unit as I see an older (lower numbered) serial number sticker underneath the new serial number sticker. The cylinder also has an 8 inch crease on the outside. Very suspicious!

 

[John.g]

The D04FM I think is not certified as being "drop tight" (even though in practice it may be) which means the downstream pressure may creep up and eventually reach the upstream pressure if there is no draw off for sufficient time, maybe overnight.
You have a PG on yours so easy to see if any increase under the above conditions, don't think this has any bearing on your cylinder noise problem, next time shower is on just check this pressure to see if its maintaining say 2.75/3.0 bar.