Pressure reducing valve question, acting funny

[wingnutty]

So I just replaced a non-functional PR valve (incoming pressure is 120 psi). I set the pressure on the new valve at 55 psi. I have a closed system and I DO NOT have a thermal expansion tank installed, I will be doing that very soon.

So I checked the pressure downstream of the PR valve today and it read 80 psi. I get that thermal expansion can play havoc, so I figured that was the issue. But to check, I turned the valves to isolate the PR valve (turned valves downstream and upstream of the PR valve) and then pushed the button on my filter to relieve the system pressure to zero. I opened back up the upstream valve and the pressure jumped back to 80 psi?! HUH? The pressure gauge and PR valve were isolated from the main house...how can the pressure reducer not reduce it to the pre-set 55 psi? Thermal expansion shouldn't have been an issue under this scenario since the it was isolated from the rest of the plumbing, right?

I re-set the PR valve to 55 and will watch it. I am confused as to why it did not stay set at 55 with a brand new PR valve?

Any ideas on what's going on?

 

[IFIXH20]

How are you setting the pressure - please tell us in detail. I notice in your other post you stated the city water pressure is 200psi. Just a thought , you may need to do a two stage PRV setup due to high pressure (200psi).

 

[wingnutty]

No, the incoming psi is 120 psi, so not too out of the ordinary.

So to set the pressure I turn all the shutoff off to isolate the PRV valve, pressure gauge and filter, then I relieve all the pressure by hitting the release button on my filter. This releases all the pressure to 0. Then I turn the bolt counter-clockwise, as instructed in the manual. I turn the incoming shut off back on and make sure that the pressure is reading 55 psi. I then turn back on the shutoff for the house and run a faucet and check the psi to make sure it still comes back to 55 psi. Once it hits 55 psi and stays, I leave.

I come back 12 hrs later and it is reading 80 psi? I then again isolated the PR valve, pressure gauge and filter and relieve the pressure by hitting the button on the filter. I turn the incoming shutoff back on (leave the house shutoff off) and the psi running through the PR valve read 80 psi again. I though for sure once I did this it would read 55 psi and that the extra psi was due to thermal expansion from the water heater, but it can't be if the house plumbing is shutoff and not influencing the PR valve?

It's a brand new PR valve, so I"m confused. I've re-set it 2 or 3 times already???? The PR valve says it can handle pressures up to 400 psi.

 

[IFIXH20]

Try setting the pressure without Isolating the PRV. Open a tub valve (cold side) or a hose bibb ( on back side of PRV) and set PRV pressure while water is moving through the system. Make sure the water heater is not heating when setting PRV pressure.

 

[wingnutty]

Ok, so I checked it today and psi was over 100! WTH! I had it set at ~50 psi.

I tried to do as you suggested and turned on a spigot while trying to adjust the pressure and it really isn't working. I turn the screw on the PRV and the pressure doesn't change while I'm turning the screw.

Can thermal expansion really bump up the psi by 50? I've been checking it regularly and it had held at 50 psi for a couple of days before I checked it today and saw it at 100.

Do you think it's a bad PRV? Or could there be another cause?

 

[johnjh2o]

Thermal expansion can raise the pressure high enough to open the relief valve on the water heater. Which opens between 125 & 150 PSI.

 

[wingnutty]

Ok, thermal expansion tank installed.

Pressure is still a bit wacky. No matter how I adjust the PRV, the pressure remains at 45 psi. When the water is running, the psi drops and when it stop running, it returns to 45 psi. When I adjust the PRV to increase the pressure, nothing happens, it remains at 45 psi (I've adjusted the PRV by isolating the valve (turning water off), adjusted when water running, the whole 9 yards, makes no difference, it always stays at 45 psi).

BUT here is where it is weird. If I adjust the PRV, whole-house pressure remains 45 psi, but when I isolate the PRV (turn water off downstream of the PRV and leave it on upstream), the pressure is different, depending on how I adjust the PRV. So if I increase the pressure on the PRV and isolate the valve, it will increase, but as soon as I turn on water to the house (downstream of PRV), it goes back to 45 psi???? I always run some water out the spigot after adjusting and it always returns to 45 psi. How could this be? Anyone have any ideas?

I'm wondering if I have a bad PRV, but it is brand new. I did get it as Ace Hardware and it isn't a top of the line Watts (which I would prefer). Maybe this valve just isn't reliable?

 

[IFIXH20]

Post some pics of prv and piping around prv.

 

[wingnutty]

Ok, here some pics.

Starting at the bottom:

1. primary shut off valve for house, there is another tee coming off near here for an irrigation line, that line has a shutoff and is off as irrigation is not being used.

2. PRV

3. Pressure Gauge

4. Tee, vertical tee serves master bath and a few spigots, shutoff on the tee right above where the photo is cut off

4. Horizontal portion of tee, this tee serves the remainder of the house.

5. Filter

6. Shutoff for the entire house not served by the vertical line (#4)

7. Not shown: thermal expansion tank is installed ~2' downstream from end of photo.

 

[IFIXH20]

There is a good possibility you may have debris lodge in the PRV from the galvanize piping or from the installation itself. Carefully open PRV to check for debris. (check inlet screen, main chamber pressure spring & cartridge)

 

[johnjh2o]

There is a good possibility you may have debris lodge in the PRV from the galvanize piping or from the installation itself. Carefully open PRV to check for debris. (check inlet screen, main chamber pressure spring & cartridge)

I agree with IFIXH2O. But the PRV you have installed doesn't have a screen, it's the lowest price one that Watts sells. If you replace it get a better model.
http://www.watts.com/pages/_products_details.asp?pid=776

 

[IFIXH20]

I like the big beefier ones too John

 

[wingnutty]

I agree with both of you. I think i will be replacing it soon. I think my previous PRV also failed to due debris possibly also

Funny thing is this 'cheap one' cost just as much as a good one, but I didn't have a good one available locally and wanted to get it installed asap. I think I'll try and return this one, seeing as it didn't work for more than a day!

 

[johnjh2o]

Try a plumbing supply house you should get a better deal there then you will get in a hardware store.