Mystery Racket

[jgh1]

Morning Folks,

We’ve got something of a doozy, and I’m hoping someone can point me in the right direction. A pipe in the crawl space vibrates like crazy. You can feel it in the floor, both downstairs and up, and it sounds like someone dropped a cellphone on vibrate into the bell of a euphonium. Sometimes the “caller” lets it ring for a moment and then hangs up, other times the thing just buzzes away for minutes on end. The Mrs. and I are not amused, especially at 1:30am. We’ve been trying to deal with this for a while, including with the assistance of some plumbers, and forums like this one, but with no luck. We have gathered some evidence and made some inferences:

*It’s worst at midday and late at night, when few other people are using water (we’re on city mains).

*There is a PRV, set to 50 psi, recently replaced. After the noise we saw pressure transients on a tattle-tale gauge; to 75psi with the old one, and to 60psi with the new.

*Shutting everything off—water main cutoff, water heater breaker, water heater cutoff, toilet feeds—reduces the frequency and intensity, but doesn’t actually eliminate the problem.

Thanks in advance,
Glen

 

[frodo]

Morning Folks,

We’ve got something of a doozy, and I’m hoping someone can point me in the right direction. A pipe in the crawl space vibrates like crazy. You can feel it in the floor, both downstairs and up, and it sounds like someone dropped a cellphone on vibrate into the bell of a euphonium. Sometimes the “caller” lets it ring for a moment and then hangs up, other times the thing just buzzes away for minutes on end. The Mrs. and I are not amused, especially at 1:30am. We’ve been trying to deal with this for a while, including with the assistance of some plumbers, and forums like this one, but with no luck. We have gathered some evidence and made some inferences:

*It’s worst at midday and late at night, when few other people are using water (we’re on city mains).

*There is a PRV, set to 50 psi, recently replaced. After the noise we saw pressure transients on a tattle-tale gauge; to 75psi with the old one, and to 60psi with the new.

*Shutting everything off—water main cutoff, water heater breaker, water heater cutoff, toilet feeds—reduces the frequency and intensity, but doesn’t actually eliminate the problem.

Thanks in advance,
Glen

do you have an expansion tank on the cold piping at the water heater?

 

[jgh1]

do you have an expansion tank on the cold piping at the water heater?

We don't. I dismissed that angle when the noise persisted with the water heater breaker, water main, and water heater valve all off/closed; prematurely? Do you conceive of the tank addressing the problem directly, or indirectly by regulating pressure in the system? Trying to learn as much as I can.

Thanks,
Glen