On May 27, 4:03*pm, "HeyBub" wrote:
Duke of Hazard wrote:
My water heater will over-pressurize and open the blow-off valve and
begin spilling water to the drain in the utility closet. I've tried
stepping down the temp. incrementally to find a position that it
likes, but nothing acceptable for showers will be acceptable for the
heater. *We've since been turning off the water supply valve to keep
it from overflowing when we're not in need of hot water.

I called a plumber and the guy mentioned that they keep cranking up
water pressure through our area to supply the folks farther out with
decent pressure. *He was wondering if we had a pressure reducing valve
in the unit and I was going to check on that before I had a plumber
physically come out. *I believe it is more a problem with excessive
water pressure coming to the tank because if we shut off the cold
water supply to the unit it will not spew water even with the
temperature elevated.

Replace the T/P valve under the theory that the most likely culprit is the
one that shows the symptom.

I agree but my post was intended to cover all possible bases

I forgot a reminder - exercise those T/P valves annually, at the same
time that you do a sediment flush and anode inspection (you do do all
that stuff, right? RIGHT?)

nate