Home>Discussions>PLUMBING>shuddering pressure reduction valve
9 posts / 0 new
Last post
chip19474
shuddering pressure reduction valve

I think my daughter's house has a shuddering pressure reduction valve (PRV). Just as the toilets are about to completely fill and stop, her pipes begin to shudder. The shuddering gradually gets softer and then goes away about 15 seconds after either toilet has stopped filling. The noise also happens after her washing machine stops filling during wash cycles. So, I'm wondering if there's no harm in lowering the water pressure at the PRV a small bit at a time between toilet flushes to see if the valve responds better??

Other than the PRV, I can't think of what else it might be. It's definitely not pipes banging from water hammer. Appreciate your thoughts.

Chip Krout
Skippack, PA

canuk
Re: shuddering pressure reduction valve
chip19474 wrote:

I think my daughter's house has a shuddering pressure reduction valve (PRV). Just as the toilets are about to completely fill and stop, her pipes begin to shudder. The shuddering gradually gets softer and then goes away about 15 seconds after either toilet has stopped filling. The noise also happens after her washing machine stops filling during wash cycles. So, I'm wondering if there's no harm in lowering the water pressure at the PRV a small bit at a time between toilet flushes to see if the valve responds better??

Other than the PRV, I can't think of what else it might be. It's definitely not pipes banging from water hammer. Appreciate your thoughts.

Chip Krout
Skippack, PA

Adjusting the PRV to lower the pressure won't hurt.

dj1
Re: shuddering pressure reduction valve

First, run a simple pressure check in different locations around the house, using a water pressure gauge in good condition. Right at the pressure reducer valve, at the washing machine, at the hose bib, etc.

If you get inconsistent readings over a period of time, or the pressure is higher than listed on the valve, your valve may be defective. Replace it.

If the pressure is normal, the problem may not be with the valve.

Do you know what type of piping you have?

johnjh2o
Re: shuddering pressure reduction valve

Even if the PRV is bad with out running any water the pressure will be the same throughout the house, the volume may not be the same depending on the piping, but the pressure will.

John

chip19474
Re: shuddering pressure reduction valve

Do you know what type of piping you have?[/QUOTE]

The supply and waste pipes are all copper. The problem started only a few weeks ago. My daughter has lived in the house for almost a year - it was built in 1982.

I don't have a gauge handy (I can get one) but I do know that she has what seems to be very good water pressure in the tubs, faucets, etc. I'm sure that the only way to tell if it's too high is to use a gauge but if setting the PRV to a lower setting, say one turn of the adjusting bolt at a time can't do any harm, I'd like to try that before calling a plumber!

Does that sound like an acceptable short term strategy!!??

dj1
Re: shuddering pressure reduction valve

OK, try it. One turn at a time. Be gentle with the retaining/locking and adjusting screws on the valve. Be sure to turn the adjusting screw in the correct direction.

johnjh2o
Re: shuddering pressure reduction valve
chip19474 wrote:

Do you know what type of piping you have?

The supply and waste pipes are all copper. The problem started only a few weeks ago. My daughter has lived in the house for almost a year - it was built in 1982.

I don't have a gauge handy (I can get one) but I do know that she has what seems to be very good water pressure in the tubs, faucets, etc. I'm sure that the only way to tell if it's too high is to use a gauge but if setting the PRV to a lower setting, say one turn of the adjusting bolt at a time can't do any harm, I'd like to try that before calling a plumber!

Does that sound like an acceptable short term strategy!!??[/QUOTE]

Turn the adjusting bolt out not in to lower the pressure.

John

Nestor
Re: shuddering pressure reduction valve

Chip19474:

Where I live there are no hills or mountains, and so we don't need pressure reducing valves on our water supply pipes.

However, I can tell you that we use pressure reducing valves on our hot water heating systems, and one of the most common problems is that people will change the pressure setting of their heating system PRV only to find out that the problem was a clogged filtration screen. The result is that once they clean the screen their PRV works properly, but their pressure setting is now out of whack.

Best to look for and clean any filtration screen in your PRV before you change it's pressure setting.

Take a look at your PRV and see if there's a large housing on the upstream end, like this:

If so, there's a filtration screen inside there, and if it's clogged up, it could be causing the PRV not to work properly:

You should also be aware that the companies that make pressure reducing valves will most often make repair kits for them. The repair kit will include a new diaphragm, new gaskets, a new seat and a new filtration screen. You just need the make and model number of your PRV, and you should be able to order a repair kit for it from most plumbing wholesalers if you pay cash. They'll just charge you the suggested list price. You can also order a filtration screen separately as a part.

I'm not sure if the design of a PRV would prevent back flow out of the filtration screen housing, but if you have isolating valves on both side of the PRV, I'd close them both before removing the screen.

Re: shuddering pressure reduction valve

My Friend.

You will want to increase the pressure at valve or change diapram or install new pressure regulator. Decreasing pressure will make the issue worse. This issue is due either to a bad diaphram in the Pressure regulator and or pressure difference between your city side pressure being greater than your resident pressure. The shuttering and hammering is from the diaphram vibrating.
If the regulator looks aged, my recommendation is to install a new one. Your resident operating pressure should be from 50 to 75 PSI, no greaer than 80! The higher the city pressure is, the quicker these diaphrams wear out. I have work on city pressures to home, greater than 175 psi, a 100 psi difference, The regulators are working over time. Hope this helps, Chris

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.