On Tue, 22 Jan 2013 19:33:11 -0500, Stumpy wrote:

So you have a relief thingy on the LINE, and not on the heater itself?
-- EA


An overpressure in the tank should pressurize the inflow and outflow too.

Especially if the water supply has a working pressure regulator on it -
I'm still putting off
adding an expansion-tank to the cold wqater supply at the HWH.