Toller wrote:
Thats about the last thing you want to do. Why would you even consider it?

There are (at least) 2 possible reasons for a check valve on the inlet
of a hot water heater.

1 - Some municipalities require a check valve to prevent the flow of
water from the house back to main.

2 - A check valve is used when a recurculating system is used to
prevent long waits for hot water at fixtures far from the heater.

If you do use a check valve, you should also use an expansion tank in
between the valve and the water heater. If you don't, you run the risk
of having water leak from your pressure relief valve when the water
heats up and has no place to go due to the check valve.

Toller wrote:
Thats about the last thing you want to do. Why would you even consider it?

"Ed" wrote in message
. net...
Should I put a back flow preventer or check valve on the water inlet on a
water heater ?