bought an old house (1942) installed new pex plumbing and all new fixtures. also a new pressure regulator. found I had a nearly plugged main water line, so replaced it with pex. when i replaced the main line i had to relocate the regulator. now the whole system; pipes and all; vibrate very loudly whenever any water supply fixture is turned on. I can eliminate it if i turn the faucet being used to minimal flow. the pressure is set at 50psi.and has been tested at that level. I am nearly convinced that the regulator may have been damaged by the rust in the old galvanized main water line that i replaced. but I would like someones opinion before replacing the regulator. thanks for the help in advance!