Last year, I had a leaky T&P valve on the water heater and after replacing it I found that the real problem was a broken water expansion tank. After replacing it, the leak was fixed. Unfortunately, the T&P is leaking again and I found the water pressure to be 62 psi and my tank is only about 51 psi.
It is my understanding that the water expansion tank should be about the same pressure as my water pressure. What's the exact method of relieving system pressure so that I can pump up more air into the expansion tank?