About a week ago, a new water heater was installed. Next day, I noticed intermittent dripping from the T&P valve. I understand it was high pressure because of thermal expansion. So, with a pressure guage, I checked the water pressure. The guage pegged out at 100. I lowered the pressure, now the tank doesn’t leak. However, I still get pressure reading at 100. Even tried a new guage that went to 300 psi. When I lower the pressure, visually it appears there is little force from the faucet and if you open a faucet while the guage is attached the pressure drops to under 30 psi. (Guages are good, I tested at the neighbors.) Usually, when I put the guage on it jumps to 50 or 60 then moves a little slower to 100. In other words, it looks like pressure is low, but I keep getting a high reading. Am I needing a PRV repair or replacement or a thermal expansion tank. Thanks….