I have a regulator coming into the house which I replaced today.

Why would I need an expansion tank now when there has not been one for the
last 9 years I have owned this house and it has not been a problem up till
now? What has changed?
Joe

wrote in message
ups.com...
do you have a anti siphon valve at the water line entrance? if so you
need a pressure tank.

with no abilty to backflow when your heater heats water it expands and
causes the valve to open.

if not you need a pressure regulator valve installed at the entrance