[rrufrano]

We have narrowed our situation down, thanks to village tinker, to repair of pop off valve.
All Points Bulletin....any handyman/woman who can fix a pop off valve, please get in touch with me.
Almost desperate here

[RICH1]

You may need an expansion tank ! Number 2 if your Water Heater Thermostat is bad , such as the water becoming too HOT, that pressure relief valve will also blow off water ! Number three, your water pressure regulator is inop or needs adj. x The POP OFF VALVE works for a reason

[villagetinker]

You can 'test' the expansion tank by tapping on the tank, it should sound dull at the bottom and ring at the top. I just replaced mine, the original (8 years old) rang dull all the way up, the new one changes to a ring at the middle. NOTE: you need to set the pre-charge to your existing water pressure, in our case this was 62 PSI. Also note when installing the new one use Teflon tape, and if the joint leaks a little, put a little more twist on the joint, use two pairs of wrenches do not apply pressure on the plastic pipe. I have previously posted the steps to do this in another thread.

[retiredguy123]

Note that a T&P (temperature and pressure) valve is designed to open when either the water temperature exceeds 210 degrees or the water pressure exceeds 150 psi. Those are extreme conditions which you would normally never experience, even if you didn't have an expansion tank. Hopefully, you just have a malfunctioning valve and don't have the conditions that would cause the valve to open as designed.

[Topspinmo]

If you’re talking about pressure relief valve very easy to replace for about 15 bucks if you have skills?