Water Pressure Regulating Valve Question

[dlow]

I am an owner of a new construction home which I moved into about 10 months ago. When I moved in, the water pressure in the home was at a normal level of about 50 PSI. Over time, it has continued to creep up to the point where it was at about 120 PSI yesterday!

I think it has been over 100 PSI for the past couple of weeks. I don't know much about plumbing at all, so I didn't take any action until I decided to do more research. Yesterday, after realizing I needed to take action, I adjusted the pressure reducing valve to 50 PSI. Since yesterday, the water pressure crept back up to 65 PSI.

1. Is this a sign the pressure reducing valve is bad?
2. Could I have caused damage to the plumbing system in my house by not fixing this sooner?

 

[Terry]

The T&P is set for 150 PSI on the water heater. Code is 80 PSI or less on a home, so therefore the PRV on yours. Normally if the PRV has failed, it won't reduce back again. I would keep an eye on it though. I think you are fine though. I've seen homes without PRV's that had high incoming pressures for years. It's is first noticed when the T&P of the water heater bleeds pressure off. It is much better to keep it under 80 though. Much.

 

[Sponsor]

 

[dlow]

The T&P is set for 150 PSI on the water heater. Code is 80 PSI or less on a home, so therefore the PRV on yours. Normally if the PRV has failed, it won't reduce back again. I would keep an eye on it though. I think you are fine though. I've seen homes without PRV's that had high incoming pressures for years. It's is first noticed when the T&P of the water heater bleeds pressure off. It is much better to keep it under 80 though. Much.

Thanks Terry for the quick response. Any idea on what could cause the water pressure to slowly creep up over time, while no changes were made to the PRV?

 

[CountryBumkin]

If your on City water main they may have increased the line pressure on their end. However a working PRV would still keep the pressure in your home in the correct range.

Do you have an expansion tank (air bladder-water) on your water heater? If yes, it may have gone bad. That could explain some jump in pressure, but probably not going from 50 psi to 100.

 

[dlow]

Yes, there is an expansion tank. Here is the setup (not shown is that I have a tankless water heater).

 

[Reach4]

The air precharge is best at the normal water pressure or maybe 1 or 2 PSI higher. The precharge is set with the water pressure=0.

The tank should be empty of water at the normal pressure. Try knocking near the top.

The bigger your WH and the higher you set your water heater temperature to, the bigger the thermal expansion tank needs to be to accept the expanded water. There are calculators and tables available.

If you dribble water from a faucet, what does the pressure go to? If you don't use any water, and you turn off (or vacation) the water heater temporarily, what happens to the water pressure? Some PRVs are rebuild-able.

 

[dlow]

The air precharge is best at the normal water pressure or maybe 1 or 2 PSI higher. The precharge is set with the water pressure=0.

The tank should be empty of water at the normal pressure. Try knocking near the top.

The bigger your WH and the higher you set your water heater temperature to, the bigger the thermal expansion tank needs to be to accept the expanded water. There are calculators and tables available.

If you dribble water from a faucet, what does the pressure go to? If you don't use any water, and you turn off (or vacation) the water heater temporarily, what happens to the water pressure? Some PRVs are rebuild-able.

As of now, with the water pressure at 65, the tank sounds like it is empty. If I dribble water from the faucet, the pressure goes down to about 60.

Yesterday, prior to making an adjustment to the PRV, it was at 120. After adjustment, it was at 50. Today, with no further adjustment, it is at 65.

Also, my home is still under the 1 year warranty by the builder, so if there is something wrong with it, then I want to help identify what needs to be fixed by the builder.

 

[hj]

A tankless heater does not need an expansion tank., since there is no thermal expansion. Your increase in pressure may be because the adjustment was no done properly, or the valve is creeping, although if they creep, the do NOT stop at a constant pressure like 65 psi.

 

[Themp]

Here is an article on when you need an expansion tank with a tank less water heater.

http://rogergriffith.com/2015/06/21/tankless-water-heaters-and-thermal-expansion-tanks/

It looks like you have a pressure gauge connected to your system in the photo you posted. When you turn off all the water and it drops to 60 PSI, how long does it take to go back to 65 PSI? Can you watch it creep up to 65 and them stop completely? They make another type of pressure gauge that you can buy and hook it to a spigot and it will show you the maximum pressure that it saw over time. You then can let this watch your pressure for 24 hours and see what it shows as the max.

http://www.homedepot.com/p/3-4-in-Plastic-Water-Pressure-Test-Gauge-DP-IWTG/100175467

 

[FullySprinklered]

PRVs seem to get wonky when they're going out. It's not that it's always too high, or always too low. I've tried to set the pressure on them a bunch of times and a couple of days later I'm called back and have to replace the valve. Apparently one of the symptoms is inconsistency.

 

[Dj2]

You need a new PRV. You can rebuild the one you have, I just think that it's better to get a new one.

 

[dlow]

Thanks everyone for the replies. This morning, it was at 60 PSI when I woke up. I left for the day and returned 10 hours later and it was up to 75 PSI with no changes.

Sounds like I need a replacement PRV. I will push to have have the builder replace it under warranty soon.

 

[dlow]

Update on my situation above. A plumber sent by the home builder (warranty repair) has come out twice and adjusted the PRV. The most recent time, about 4 weeks ago, he adjusted the water pressure to about 60 to 62. He blamed the creep up in water pressure on the locking nut being loose (but I know for sure the nut wasn't loose either time. he was the one who adjusted it the first time).

The water pressure is starting to slowly creep up again, it is at about 68, and I am concerned it will continue to creep. Trying to figure out how I can convince the home builder that it needs replacement, not continually adjusting it. My home warranty is up in a few weeks.

Also, has anyone used the following type of PRV? If so, wanted to get your thoughts on the quality

 

[CountryBumkin]

I haven't seen that valve before - but I don't like the idea of the plastic on the valve. I think the plastic will deteriorate over time. A well built brass valve is the way to go. IMO.

 

[FullySprinklered]

Replace the PRV before the contractor runs the clock out on you. His plumber is dumb as a bag of hammers.

 

[MACPLUMB]

that is not plastic it is composite material, but what you need is a Thermal Expansion tank installed on the cold side of your water heater
the reason the pressure keeps creeping up is because when the water heater recovers hot water it expands because you have a new house with no leaky faucets, running toilets there is no where for this extra water to go, when ever a faucet is opened or turned on or something else reliefs the extra pressure

 

[dlow]

that is not plastic it is composite material, but what you need is a Thermal Expansion tank installed on the cold side of your water heater
the reason the pressure keeps creeping up is because when the water heater recovers hot water it expands because you have a new house with no leaky faucets, running toilets there is no where for this extra water to go, when ever a faucet is opened or turned on or something else reliefs the extra pressure

Thanks. Based on my post #5 above with picture, is the Thermal Expansion Tank installed in the wrong location?

 

[Reach4]

Based on my post #5 above with picture, is the Thermal Expansion Tank installed in the wrong location?

Probably not, but it is not clear what your photo shows. Is the water coming in from your slab to the bottom of the PRV, and the expansion tank is on the output side? That is how it should be.

 

[dlow]

Probably not, but it is not clear what your photo shows. Is the water coming in from your slab to the bottom of the PRV, and the expansion tank is on the output side? That is how it should be.

Yes, expansion tank is installed after the PRV, as a branch of the cold water intake into the tankless water heater.

Could the thermal expansion tank also be an issue? Not sure what is was pressurized to.

 

[Reach4]

Replace the PRV before the contractor runs the clock out on you. His plumber is dumb as a bag of hammers.

Maybe. Maybe he knows but wants to come back.

Yes, expansion tank is installed after the PRV, as a branch of the cold water intake into the tankless water heater.

Just checking.

Could the thermal expansion tank also be an issue? Not sure what is was pressurized to.

Not according to #8, and I certainly agree. However the tank could hide a leaky PRV for a while. I would set the precharge to maybe 52 to 55 PSI with your 50 PSI PRV setting.

I agree that your PRV should be replaced or repaired. What is the make and model of your PRV?