"Bubba" wrote in message
...

Nope! Check the pressure with all faucets closed. Water heater burner
or heating element not on. If pressure is managable, then turn the
water heater burner or electric elements on. Now watch the water
pressure. IF it starts rising, you most likely have a backflow
preventer in the line and you will need an expansion tank. The
pressure regulator on the incoming line to the house is just to
control the amount of pressure you want to your home, usually because
the pressure provided by the city is too high.
Bubba


IOW, its probly the other water heater that's causing the ( closed ) system
to over pressurize.

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SVL