Originally Posted by bob_okc
My water heater just started whining while the hot water is being used. Used the pressure relief valve to make certain that there was no air. It works fine and it's not leaking.
There is supposed to be
air in the top of the heater heater tank....(that "head of air" allows for expansion as the water heats).
1.) Turn your WH OFF,
2.) Drain the tank,
3.) Refill it, (with the P&T relief valve closed), to re-establish the necessary/required "head of air"
3.) Re-light it and allow it to heat the water
'96 Safari, 10 gal Suburban WH