wrote in message

A replacement regulator likely comes with the backflow preventer
required by most current plumbing codes which means you also need the
expansion tank to account for the expansion of heated water since the
backflow preventer will not allow water to flow back to the street to
relieve overpressure.

With a backflow preventer and no expansion tank you will typically see
frequent discharge from the T&P valve on the water heater as it relieves
the overpressure.

Pete C.

Ah, thank you. Very clear. Is there some reason that it's a bad idea to
simply allow the discharge from the T&P valve to occur? The water
heater is outside the house, not in an area that will be damaged by
water.


I believe I've read that some regulators can be rebuilt, without the need to do
plumbing. It might be worth looking into.

Bob