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Author:
gw (CT)
The water pipes in my house occasionally hammered loudly. The noise seemed to be loudest at the point of the incoming water line, from either the water meter or the pressure reducing valve. Water pressure measured 45 psi when flowing but quickly increased to 120 psi as water flow stopped due to closing valves (indicating the PRV had internal leak-through). Upon disassembling the PRV, I found the cartridge piston seals and the brass cylinder were badly worn. Based upon this, I thought the worn-out PRV was the source of the water hammering as well (due to piston chattering when attempting to regulate pressure).
I replaced the PRV (a 3/4" Cash Acme EB-86) and now the pressure holds steady where it is set. However, now the water pipes pulse and hammer terribly (approx 3 pulses per second) while water is running. While pulsing, the water pressure gage bounces rapidly between 20 - 100 psi. The only way to avoid this pulsing is to begin water flow very gradually. In case this is relevant: the new PRV is a Cash Acme EB-45 but because a 1" PRV was delivered, I had to reduce both ports to 3/4".
I would like to know whether this water pulsing is being caused by the new PRV or by the water meter (or possibly something else).
:...Should I try yet another PRV (another brand, another type, the intended 3/4" size)?
:...Should I install a water hammer arrestor (if so, where)?
: Other suggestions?
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Author:
packy (MA)
putting on my leiutenant columbo hat and coat, i would venture a guess that if the pipes did not rattle before the new PRV was installed but rattle after it was installed, the PRV becomes the prime suspect.
i can't imagine that reducing the inlet and outlet would have anything to do with this.
if there is an inlet screen filter on your PRV, check it for debris ???
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Author:
hj (AZ)
You are describing the symptoms when a PRV is installed backwards.
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Author:
gw (CT)
hj: Thank you for your input. The PRV is installed with the arrow facing the correct direction of expected flow. If this PRV is installed in the opposite direction, it acts almost as a 1-way valve and there is only a trickle of flow, regardless of pressure setting.
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Author:
gw (CT)
packy: Thank you for your response. I also tend to think that the pulsing is being caused by the PRV. My only uncertainty comes from this being a new PRV and the pulsing did occasionally occur with the old PRV.
Here are a few more clues for Columbo: The pulsing began several months ago, occurred randomly and then diminished to a fairly rare occurrence for the past month or so. During the past month I also noticed two toilet fill valves (old style ball float) that were not shutting off; so I replaced those. A humidifier tap valve (i.e. ice maker valve) also began leaking in my basement; so I tightened the clamp to stop the leaking there as well. During this time the vibrating pipes began again. There was also a loud shuttering (sounded like a goose honking) in the pipes just after toilet valves would close.
I attached a pressure gage and noticed that, just after valves closed, pressure gradually increased from 45 psi to 120 psi as the toilet vales or pipes make the "goose honking" sound. My assumption is that the toilet flush valves not shutting off and the tapping valve leaks were due to over-pressure caused by the failed PRV. Furthermore, when water began to flow, there was initially no pulsing in the pipes. The pulsing began only after the water pressure dropped below 45 psi. This led me to believe that the PRV was also the cause of the pulsing because the internal piston *should* not move from the closed position until the outlet pressure dropped below the regulator set point. I imagined that, as pressure fell within activation range, the PRV piston began to chatter inside the PRV and this was amplified by the velocity of water in the pipes. In my mind, this also explained why these symptoms had disappeared (or minimized) for several months. The leaking toilets probably helped to bleed off the excess pressure from the internal leak-by of the PRV, thus preventing pressures from reaching 115 psi and preventing the PRV piston from attempting to forcefully slam to the closed position. I had convinced myself that this was the cause... until I replaced the PRV and now the pulsing is worse than ever.
While it is certainly possible that I received a defective PRV, I want to at least verify these thoughts with a professional before I break out the torch and work on soldering in an anti-hammer tank or return the PRV. The pressure is now being regulated perfectly but the pulsing and hammering is worse than ever. Initially the pulsing sound *seemed* to be coming from the water meter (and the "pulses" could be seen in the rotation of the red flow indicator on the meter) but, because the meter is located only a few inches form the PRV, it is very difficult to be sure of the source of pulses.
: I am curious to know if anyone on this forum has witnessed either a water meter or a PRV causing this type of pulsing and hammering.
: Assuming the PRV is the cause, how can I be assured that replacing the PRV (again) would correct the problem this time?
: The PRV I used is a half-cartridge style. Is another style of PRV recommended for eliminating pulsing?
: Would installing a water hammer arrestor correct this issue by dampening the pressure pulses that are returning to the PRV?
Thank you to everyone who takes the time to read through and respond to these posts!
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Author:
gw (CT)
For the benefit of anyone else with this situation (loud "goose honking" sound resonating through water pipes), I solved my problem by replacing the water pressure regulator valve. The problem was challenging to diagnose initially because the sound occurred with the old pressure regulator (which was known to be defective) but the problem was not cured by replacing the pressure regulator valve. The replacement valve I had used regulated pressure properly but the valve chattered as it reached final pressure (much like the effect of squeezing the neck of a ballon as air escapes). Replacing that valve with a new PRV finally cured the problem. For reference, the original (failed, noisy) PRV was a Cash-Acme EB-86; the second (noisy) PRV was a Cash-Acme EB-45LF and the final (good) PRV is a Watts N45B.
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