George,

I can't find that series of posts that recommend putting a Canadian spec pressure-temp valve on the water heater because of the problem you indicate. However, Rob Mueller did post this, indicating that it was not unheard of. His message #264278:

"G'day,

One of the problems a coach that has rubber lines back to the water heater runs into is that the water temp in the water heater gets
heated to the same temperature as the engine cooling water. When the water pump is turned on water flows out of the temp / pressure
relief valve until the temperature of the water in the water heater is reduced below the setting of the temperature relief valve.

At first it thought using metal lines wouldn't be a good idea as you would lose heat through the lines, however, that might be a
good thing.

Rick,

Let us know if you experience the problem noted in the first paragraph."



Somebody will remember about the Canadian valve. They allow hotter hot water heaters up there.

Best,

Carey