Water pressure too high?

[Michael Larson]

Originally Posted by rbrady

Doesn't a pressure relief valve prevent pressure relief through the building supply? I thought they did not allow back flow.

Not always true.

Series: PRV-1
Description: Small Diameter Water Pressure Reducing Valves
Available Sizes: 1/2 to 1 in. (15 to 25mm)

Series PRV-1 Water Pressure Reducing Valves are designed to reduce incoming water pressure to a sensible level to protect plumbing system components and reduce water consumption. Their bronze bodies are suitable for water supply pressures up to 300psi (20.7 bar) and may be adjusted from 25 – 75psi (1.7– 5.2 bar). The standard setting is 50psi (3.4 bar). All parts are easily serviceable without removing the valve from the line. The standard bypass feature permits the flow of water back through the valve into the main when pressures, due to thermal expansion on the outlet side of the valve, exceed the pressure in the main.

• • Installation Instructions
  • Specification Sheet

[psiposs]

The home is occupied and though I like the idea to measure at the laundry supply, I don't want to move a washing machine or disconnect hoses and turn water valves rarely used to measure inside the house. I didn't see a pressure regulator in the crawl space either. I will just note what I saw OUTSIDE and make a note about inside pressure.
Otherwise I suppose I'd need a handful of adapters to connect a faucet to the gauge somewhere in the house.

[Roy D. Cooke, Sr]

Originally Posted by psiposs

The home is occupied and though I like the idea to measure at the laundry supply, I don't want to move a washing machine or disconnect hoses and turn water valves rarely used to measure inside the house. I didn't see a pressure regulator in the crawl space either. I will just note what I saw OUTSIDE and make a note about inside pressure.
Otherwise I suppose I'd need a handful of adapters to connect a faucet to the gauge somewhere in the house.

If there are no taps on in the home regardless where you measure you will get the same pressure reading.

...Cookie

[Jeffrey R. Pope]

Originally Posted by rbrady

Doesn't a pressure relief valve prevent pressure relief through the building supply? I thought they did not allow back flow.

I assume you mean a pressure reducing valve, rather than a pressure relief valve, in which case, Michael posted the pertinent information.

As Jim pointed out, even when using the same model code (the UPC in this case), local jurisdictions will vary in their requirements.

[Michael Larson]

Originally Posted by jpope

I assume you mean a pressure reducing valve, rather than a pressure relief valve, in which case, Michael posted the pertinent information.

As Jim pointed out, even when using the same model code (the UPC in this case), local jurisdictions will vary in their requirements.

Good catch Mr Pope. I read his post as meaning reducing not relieving.

[rbrady]

Originally Posted by jpope

I assume you mean a pressure reducing valve, rather than a pressure relief valve

That's right, you're absolutely correct!

I have seen at least one pressure relief valves leaking after the water heater turned on, most likely due to a no-backflow type pressure reducing valve.

[Jack L. Gilleland]

If there is no pressure reducing valve at the home you can get the pressure reading at the hose bibb. If there is a pressure reducing valve check to see if the hose bibbs come off of the line prior to the valve.

[Russel Ray]

I find exterior hose bibs with higher water pressures almost all the time....
...if there is a landscape irrigation system present, and when I did landscaping in Texas, we also used a higher pressure for the irrigation system.

For the house, 40-80 psi, although I personally prefer 40.

Several years ago I found 176 psi in a home that was only a couple of years old. The seller had already disclosed that he had been having a lot of plumbing problems but that his plumber couldn't determine what was wrong. Hmmmmmmmm. Maybe need a new plumber? I explained to my Clients what was wrong, and they bought the house. They are also currently good friends of mine, and in four years of owning the house, have had no problems after having my plumber install a new pressure regulator and lower the pressure to 40 psi.

[gporter]

Originally Posted by rray

I find exterior hose bibs with higher water pressures almost all the time....
...if there is a landscape irrigation system present, and when I did landscaping in Texas, we also used a higher pressure for the irrigation system.

For the house, 40-80 psi, although I personally prefer 40.

Several years ago I found 176 psi in a home that was only a couple of years old. The seller had already disclosed that he had been having a lot of plumbing problems but that his plumber couldn't determine what was wrong. Hmmmmmmmm. Maybe need a new plumber? I explained to my Clients what was wrong, and they bought the house. They are also currently good friends of mine, and in four years of owning the house, have had no problems after having my plumber install a new pressure regulator and lower the pressure to 40 psi.

wow.

[Frank P. Newman]

Originally Posted by rcooke

If there are no taps on in the home regardless where you measure you will get the same pressure reading.

...Cookie

That is correct - so it really doesn't matter where you measure to determine what pressure all devices in the home must be able to withstand. "In use" pressure will indeed be different downstream of a pressure reducing valve.