A plumber recently installed a new pressure reduction valve and expansion tank in my house (which previously had neither) because the water pressure was unusually high. About a week after the install, I started hearing a low, loud foghorn noise whenever I turned on any faucet in the house or flushed the toilet. The noise comes a few seconds after the water comes on, and it typically only happens after periods of no water usage, such as in the morning or when I get home from work. I spoke to the plumber who is coming back next week, and he doesn't think the problem is the PVR unit itself, but everything I'm seeing online indicates that usually is the problem. What could be causing this noise?
Update: the plumber came out and agreed it sounds like the PRV. He replaced it, and two days later I haven't heard the noise once.
Best Answer
To me it sounds like the Pressure Reducing valve or Regulator is not properly sized but it could be a less expensive model also.
The noise you are hearing is the regulator a spring tensioned device getting close to its pressure setting and chattering this often sounds like a fog horn on water pipes in some cases it can be a high pitched also. I have found that high end valves or water regulators have fewer problems but these are expensive.
The pressure tank will usually dampen the noise is your air charge close to your operating pressure? If the air charge is set up like a well down at 30-40 psi the bladder will be flattened with a 60 psi tank pressure.
If your PRV is set at 60 your pressure tank should be charged to 56-58 and that will help dampen the noise as the air dampens the vibrations.