Regulator pressure increases over time - why??

[David]

Problem: House pressure rises during the night from 40 PSI to 70 PSI. Is incoming pressure regulator failing?

Water meter pit is 175 feet from house. Pressure regulator is in ground next to meter pit. City water pressure in meter put approximately 100 PSI (according to city). Regulator is adjusted so that incoming house water pressure is about 40 PSI as measured on gauge in house. Pressure gauge in house is located on the house piping as it enters basement from the outside. Downstream of this gauge is check valve followed by thermal expansion tank. Also have pressure gauge screwed into hot water tank drain valve. Note that pressure readings on both gauges are approximately the same (within the accuracies of the gauges).

During the day when we are home and using the water, pressure is relatively constant from 38-42 PSI (within the accuracy of the gauge). However in the morning before we use the water, the pressure has risen overnight to 65-70 PSI.

Prior to leaving on a recent vacation, I shut valves in basement and released pressure on house piping. The pressure on the incoming water piping pressure gauge was 40 PSI and the pressure on the hot water tank gauge was about 0 PSI. When I returned from vacation, the pressure on the incoming water piping pressure gauge had risen to 70 PSI and the pressure on the hot water tank gauge was still at about 0 PSI.

Does this indicate a problem with the pressure regulator? If so, what is going wrong with the regulator mechanism? Should I replace the regulator?

[Speedy Jim]

Yes. Even the tiniest of leakage past the regulator will slowly increase downstream pressure. The valves are quite rugged and the leakage could simply be due to dirt accumulation. But, hey, if you have to remove the thing to clean it you might as well replace it.

Plan "B": Leave some faucet open to drip just enough to compensate.

Jim

[SQLit]

Not necessarily. A lot of places pump at night into storage containers cause it is cheaper. You need a gauge on the line side to make the determination.

My pressure regulator is set at 40 psi at the main incoming line.

[Playintennis5274]

th>Not necessarily. A lot of places pump at night into storage containers cause

that wouldn't matter. that's the whole ppurpose of the regulator. No matter what they (water co.) do on the other side of the meter, his pressure won't rise above the 40p.s.i Of course it can drop though.

[Chris Lewis]

Plan "C": ignore it. Unless you're worried about your plumbing rupturing from 70PSI, it's not a problem. It'll instantly drop to 40PSI the moment you start using it.

[Harry K]

Unless the regulator is leaking slightly which is what it sounds like is happening.

Harry K

[Playintennis5274]

i know that. . . i was commenting on the guy who said some crap about pumps.

[Jeff Wisnia]

Based on the OP's thorough description I'd say it HAS to be an imperfect presure reducing valve.

My mind started running off in the direction of the pressure reducing valve being "perfect" but the incoming water was real cold, and the house warmer, which could cause a pressure increase as the water warmed up and expanded during the night. Then I went back and read that he had a thermal expansion tank in the system, which killed that bright idea.

The pressure reducing valve must be weeping more than just a tiny bit, because that thermal expansion tank (assuming it IS in proper shape) would have to accept quite a bit of water before it'd "bottom out" and permit the full line pressure.

Chances are a new valve, or a rebuild of the present one would reduce the weepage to the point where the expansion tank could easily handle it, certainly during an overnight idle period.

Jeff

[David]

Some more data. I tried the following. Open house faucet. Pressue drops below 40 PSI, an expected result when using water. Then close whole house shut off valve. Pressure should rise within several seconds to line pressure comping out of regulator, right? Instead, I have to wait several MINUTES for pressure to rise. Does this further add to the evidence that the regulator shoudl be replaced?

[MLD]

A pressure regulator is meant to hold (regulate) the downstream pressure when there is flow. When the system is shut down (faucet closed) the regulator shuts down also. If the system pressure rises to the upstream level it would mean (in my opinion) that there is some leakage past the shutoff seals. To be sure, one would need a schematic of the regulating valve to understand just how it works. Most regulators have a differential area so that the forces acting on the valves are such that if the downstream pressure rises above the controlled, or regulated pressure, the valve will close. MLD

MLD

[Playintennis5274]

flow or no flow a regulator maintains the it's set for. go to home depot & in the sprinkler area they have little pressure guages for 10.00 BEFORE the pressure regulator take a reading (at your meter u should have some little threaded openings w/ little valve lever on the anti syphon valve) take a reading, then AFTER the regulator find a spot and take a reading. But i can guarentee you the regulator is slowly bypassing water. they're made of brass and soft the seat or the seal surface has cecome imperfect and is leaking.

[TomG]

Hi there, I found this forum as the only example of what was happening to my PRV. It was the THIRD installed to a system with 7bar(!) mains pressure, the previous two were not that cheap - Honeywell adjustable pressure valves are the most commonly used in the UK I think. They both failed within a week or so making horrid squealing noises.

Installed a Jet Systems valve, much higher quality. Seemed to work fine. Then one day I was adding more parts to the system for a water softener, and tightening up a joint that was weeping. Basically the pipes had some knocking about and tapping. That day, whether coincidence or otherwise, the prv worked fine when water was running (set to 3 bar, ran at 2.6) but then slowly crept up to 7 over maybe 10-20 minutes. So it would seem to be leaking through. Perhaps a piece of debris caught (although it should have a filter!) Read this thread and realised I should replace it AGAIN. Later the next day, inexplicably, the valve worked perfectly again, and has done since. Maybe there was a tiny debris blockage and it was dislodged? It’s the only thing I can think. Mains pressure is much the same.

Any ideas? Should I replace the valve before I put sink unit and cupboards infront of it and make that much more difficult in the future? The period at 7 bar made the dishwasher leak a little, I don’t want that to happen without warning! Thanks for the advice. Tom

[micky]

This seems clearly to be an initial post. But 98% of the time when we see a post from homeowners, it's a reply, it doesn't quote the original post, and we have to guess what that said.

TomG, did you do anything to get your post to show up on Usenet (not part of the world wide web, but where the big boys hang out)?

[Marilyn Manson]

I'm not sure what you are seeing to make you think that this is an initial post.

I see 11 preceding posts, all posted during October 2004. The link at the bottom of Tom's post shows the title of the original thread.

[Dean Hoffman]

Google Groups shows Tom's post as being six hours ago, at 1:15 pm. I wonder if putting two regulators in series would help his situation.

[gfretwell]

noises.

A filter might be more help if he thinks "tiny debris blockage" is the problem. 102 PSI (7 Bar) should not be an issue for any decent regulator. Are the aerator screens in the faucets plugging up?

[Marilyn Manson]

Right, ~16 years after the original thread apparently fizzled out.

[micky]

I was going by how it was phrased. I guess I would have said something different if I'd looked at the link. I did that for two threads and afaic, that's enough.

So it's still true that afaict we see only follow-up posts from them and not original posts, that likely give the entire situation and question.

I'm going to skip even more of their posts than I have.

[Marilyn Manson]

No, not always.

In this case, I see the the original post from David, dated Oct 11, 2004, 12:54:16 PM

It starts with this and is followed by a detail explanation of the entire situation:

"Problem: House pressure rises during the night from 40 PSI to 70 PSI. Is incoming pressure regulator failing?"

[gfretwell]

I have never seen an "original post" ported to AHR. It may be the first post from the poster but they found the thread in Google and started there. People don't seem to start new threads in Homeowner Hub very often it seems. A am also not sure when they started cross posting to AHR but I can remember from before it started.