I have a 21yr old State/Courier Gas fired water heater (old but looking/working great.)
While doing annual maintenance (checking TPR & draining), I noticed that the cold water supply pipe is actually very warm to the touch, almost hot. Following the water supply line back toward the source, it gradually cools down to a point about 6’ out, where it is then cold to the touch.
It’s apparent that either the hot water is backing up into the cold water supply, or just by conduction the WH is warming the supply pipe.
QUESTION: Is this an issue to be concerned about? If so what are some of the possible repairs/concerns?
Water expands when it is heated. The water has only one way to expand and that is back up the supply line as long as there is no check valve in the line to stop this flow. If there is a check valve in the supply line then an expanstion tank is recommended.
The is also a fill tube that drops from the top of the WH to the bottom so that the cold water is heated before it can escape to the system. In a heater that old it is very possible that that tube doesn’t exist any more. So as the hot water rises to the top of the heater it can either go out the HW supply or into the cold water line. This is just another possibility.
I have a brand new WH, it does it and every WH I ever had did it also. The only way to prevent it is to completely isolate the cold water supply from the WH. The laws of physics demands that the heat is transferred thru the easiest path(the cold water).
Thanks everyone… Like I said, it seems like it is working fine. Since I’m not a plumber, nor do I play one on TV, I didn’t know if it was something that could be a cause of concern. I know enough about Hot Water Heaters to know that they can and do blow up. Thanks again for all the advice. We’ll let it go a while longer and see how it lasts. So far it’s been an excellent appliance, with virtually no maintenance.