todd wrote:

My home is two stories, with a basement, in the Northeast. Public
water enters the basement, then there is a ball valve, regulator,
meter, dual check valve, and another ball valve. Over the last several
weeks (since it has gotten cooler), most mornings there is no water at
the second story of the house. I then go to the first floor and try
the kitchen faucet. If there is good flow in the kitchen, it will
usually then charge the system up to the second floor. If there is no
water on the first floor, I have to go to the basement and close and
open the downstream ball valve. This will then charge the whole house.
Closing and opening the upstream ball valve in the basement does not
charge the system. I figure my problem is either the regulator or the
dual check valve. Anyone have an idea how to remedy this, and what is
a dual check valve?


http://www.crd.bc.ca/water/crossconn...checkvalve.htm

The valve is there to prevent water in the house lines from
backing up into the street Main.

I bet the dual check diaphragm is sticking under pressure.
Since you have a PRV and a check, the water heater must have
an expansion tank. Does yours? Without one, system
pressure can go above normal.

Another possible is that the street Main pressure suddenly
drops overnight, causing the check to jam.

Jim