This is expected, as the cold water coming in is heated, it expands and increases pressure in the whole system. Some houses will have backflow preventers or pressure regulators on the main line coming in that prevents this added pressure from going back into the city's lines, and you end up with your case. Specifics of yo uinstallation will impact where and what is over-pressurized (normally the entire system is).
Most installations, this added pressure (a few psi) isn't above the operating pressures, but I agree, it is annoying.
I had the same situation and added a thermal expansion tank to remedy it. Fairly easy install.
Happy to explain further
|