Originally Posted by harley
Turns out there's some sort of pressure release valve on the waterheater, and it was screwed in too tight. Created a pressure backup in the system,
They all said they'd never seen anything like it before.
Is this your current home? I'd want to look into it more if it were mine. The pressure thing on a water heater is totally a safety measure. It should not be getting activated in normal use, only in case of a fault.
If it is tripping normally, and that is relieving pressure on your plumbing, something is wrong. WH set to too high a temp and boiling, air (steam) in the WH, something.
edit - I got curious, here's a link: