Regulator Replaced/Still occasional High Pressure & PR Valve on Water

[MasterPlumbersKeymaster]

We live at the bottom of a hill and have city water.

Recently we starting having problems with occasional high bursts of water pressure when faucets were turned on and noticed dripping from the PR Valve on the Water Heater. (Water heater is ~9 years old) We blew out toilet components and both hot and cold lines in the same bathroom sink.

Since we have owned the home 2+ years we have always had occasional banging pipes when the faucets or toilets turn on, but not off. Water hammer arrestors were installed on both the hot and cold lines of the washer to no avail.

We just had the pressure regulator replaced, however we are still experiencing occasional bursts of high pressure and leaking from the valve. I checked and the water company says no local work done.

What next? Expansion tank? We have not replaced the PR valve but it’s on the list to do. How hard are they to install?

[PLUMBILLParticipant]

If you are going to replace your pressure reducing valve I would do that prior to installing the expansion tank on the cold water pipe to your water heater.

Have you tested your water pressure with a gauge or cleaned the seating area of your pressure reducing valve?

[Retired plbg1Participant]

Sounds like you have a buildup of pressure and your PRV leaves it go by, I think they make PRV with a relief valve built in check with watts.

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Art retired plbg

[turdchaserParticipant]

You should absolutely have an expansion tank on the system. Having a PRV on the piping is the same as having a check valve. Water will flow into the house but not out. When the water heater kicks on and heats water the water expands building pressure up to the point that the T&P valve on the water heater opens and spits water out in a closed system (one with a one way valve in it). In a open system the expanding hot water will actually move backwards in the line and disipate the buildup of pressure into the miles and miles of municipal water piping.
In the States it is not an acceptable practice to allow the T&P to operate like this. ( T&P gets weeker with age and keeps opening at a less and less pressure or fails to open from rust and corrosion buildup and your tank BLOWS UP or the constant increase of water pressure, up to the point of 150psi, it takes to open the T&P tears apart the rest of your plumbing system). However allowing the T&P to operate like this in other Nations seems to be a common practice.
So do have an expansion tank and also verify the PRV has not failed and your house pressure is in the 50psi to 70psi range.

» This message has been edited by turdchaser on 12 March 2004

[SelgasParticipant]

Turdchaser

Just to keep you informed as to what we do here with a hot water TPR valve fitted water heater – we run the tpr valve discharge to waste but……. we also fit a relief valve on the cold water inlet to the water heater which is set at 70% of the pressure of the hot water relief so in fact when the water is being heated the cold water valve discharges cooler water to waste. But heck we ain’t got no water shortages or water meters in most places in this here God’s Own Country so it don’t matter much.

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Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians

[racefanoneParticipant]

Try putting a thermal expansion ball valve on the cold water supply line to the water heater.The ball valve is used in place of the expansion tank .I use them on every heater I install.

[turdchaserParticipant]

Peter,
Thanks for the insight it makes a little more since now.
Turd

[PLUMBILLParticipant]

I know they have pressure reducing valves with a thermal expansion by-pass feature but what is an thermal expansion ball valve and who makes them?

Or are you talking about the Watts Governor 80 ball cock?

» This message has been edited by PLUMBILL on 15 March 2004

[racefanoneParticipant]

The valve I use is made by Watts. It is a ball valve with a releif type valve on the side. It is set at 125 psi pressure and 210 degrees.F.The releif valve has a 3/8″ compression nut for 3/8″o.d. copper which must be piped to a drain.Not familiar with the valve you mentioned.The ball valve can also be used as a shutoff for the cold water to the tank.

» This message has been edited by racefanone on 16 March 2004

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