CoHotelier
New Member
Symptom:
The prv (Watts LF25aub 1”) howls or sings loudly when it’s opening and closing, but not during the flow event (toilet, shower, doesn’t matter). If I throttle down flow at a hose bib, I can get it to howl/resonate continuously at very low flow.
System Details:
The building has 4 rooms, each with sink/tub/shower/lav. It is a standalone addition to our motel, so quite often two or three - and potentially four sets of fixtures could be running at once.
Incoming town line pressure is 175psi as shown on our nearby fire system gauge on a dedicated 2” line. Domestic 1” Ts off of that line outside of the building.
The incoming domestic line is 1” with a 1” Watts LF25aub PRV followed by a Watts Reduced Pressure Backflow Preventer.
I’ve had the PRV open, no obvious defects, and screen isn’t clogged at all.
Grabbing, adding mass, tension, etc to the PRV makes no difference
I did add an expansion tank on the system near the domestic hot water heater to remove any home-side back pressure concerns, however I don’t think internal line pressure from expansion is a problem as the PRV is noisy on both opening and closing… I don’t see how line pressure build up from heated water would act fast enough to cause a problem on close, or after a full flow event… plus it’s all behind a backflow device.
Adjusting pressure up and down seems to have an erratic, but not reliable effect. If I crank the pressure up I can get it quieter, but not silent, and not reliably quiet. Even at near 80psi it can still be noisy, it’s erractic.
I’ve got a couple potential reasons this is happening as I see it…
Solutions are…
Thanks all for any attention you can give this.
The prv (Watts LF25aub 1”) howls or sings loudly when it’s opening and closing, but not during the flow event (toilet, shower, doesn’t matter). If I throttle down flow at a hose bib, I can get it to howl/resonate continuously at very low flow.
System Details:
The building has 4 rooms, each with sink/tub/shower/lav. It is a standalone addition to our motel, so quite often two or three - and potentially four sets of fixtures could be running at once.
Incoming town line pressure is 175psi as shown on our nearby fire system gauge on a dedicated 2” line. Domestic 1” Ts off of that line outside of the building.
The incoming domestic line is 1” with a 1” Watts LF25aub PRV followed by a Watts Reduced Pressure Backflow Preventer.
I’ve had the PRV open, no obvious defects, and screen isn’t clogged at all.
Grabbing, adding mass, tension, etc to the PRV makes no difference
I did add an expansion tank on the system near the domestic hot water heater to remove any home-side back pressure concerns, however I don’t think internal line pressure from expansion is a problem as the PRV is noisy on both opening and closing… I don’t see how line pressure build up from heated water would act fast enough to cause a problem on close, or after a full flow event… plus it’s all behind a backflow device.
Adjusting pressure up and down seems to have an erratic, but not reliable effect. If I crank the pressure up I can get it quieter, but not silent, and not reliably quiet. Even at near 80psi it can still be noisy, it’s erractic.
I’ve got a couple potential reasons this is happening as I see it…
- Outside pressure at 175psi throttled down to 60psi is too big of a drop at very low flow conditions (opening and closing) for the prv.
- The PRV is oversized at 1” for the four bedroom unit and is outside of its ideal operating conditions trying to handle high pressure and very low flow.
- The PRV is faulty (it’s six months old, but the noise started immediately upon install).
Solutions are…
- Buy a rebuilt kit for $50 and see if that fixes it.
- Replace it with a new same unit, Watts 1” (Logic being even I used a rebuilt kid there could be something wrong with the hard parts or the cast of the original unit that a rebuilt kit wouldn’t address and it’d be a wasted $50 and time). Same unit would ease install effort.
- Replace it with a new same brand/model lf25aub unit, but in ¾” instead of 1”. A little repiping but nothing crazy.
- Replace it with a different brand 1” (I had looked at the 1” Caleffi 535 series with gauge, but not sure it’s right for my application).
Thanks all for any attention you can give this.
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