Whistling New PRV and Pressure Gauges


Old 01-01-14, 04:48 PM
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Whistling New PRV and Pressure Gauges

Installed a new 25 AUB Watts PRV with pressure guages up stream and downstream of PRV. Experienced intermittent whistling whenever the city inlet side pressure approached 80-90psi. This typically happens at very late at night when noone in the neighborhood is using water. The down stream pressure is set to 65 psi. I made some adjustments to the PRV but it was like playing wack-a-mole. I would wait for the whistling to occur, leave the water running and run downstairs and adjust the PRV until the whistling would stop. However the whistling would just reappear at a different flow rate/upstream pressure/downstream pressure combination.

I listened closely and discovered the whistling was coming from the pressure gauges I installed. I removed them and replaced them with plugs and 98% of the whistling went away. But I still get that annoying whistle coming from the PRV 2% of the time. So it would appear the PRV is whistling but the mechanical components of the pressure gauges are resonating and amplifying the sound.


1.) Are there pressure gauges that don't resonate or if they do have a resonant frequency very far away from the PRV whistling mode?

2.)Has anyone heard of the watts 25AUB PRV being particularly problematic in this way? (I was thinking about changing it out but it is expensive. It has already been replaced once for a different reason so this one will be on my dime.)

3.) Any other ideas for eliminating the problem.
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Old 01-01-14, 07:07 PM
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I've never heard of a PRV whistling before (though maybe the plumbers on the forum have experienced it before). I would lean towards maybe a bad washer on the main shutoff valve or the main valve not fully open.
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