Water Pump Hot and Cold

[BaconLover]

We just noticed that when using the water pump that when you turn on the cold water faucet (either kitchen or bathroom sink) that when the pump turns on, a bit of hot water comes through. Is this normal or do I have some kind of leak?

The one thing I need to test is whether I get cold water when I turn on the hot water faucet. I’ll do that this weekend, but I thought I would ask if others have had this problem and what the cause could be. Thanks in advance!

[Bill]

It is normal, it is annoying, it can be fixed without too much monetary cost - but there is a possible high cost involved. Here's the explanation.

The water heater fills from the cold-water pipe, of course. As the water inside the heater gets hot, the air in the space at the top of the heater tank also gets hot - and of course air expands as it gets warm. This increases the pressure in the tank a bit, which forces a small amount of heated water back into the cold water fill pipe. When you turn on the cold water faucet, the first thing you get is that shot of warm water that is sitting in the cold water pipe.

You can prevent this by installing an anti-backflow valve in the water heater's cold water inlet, so heated water can't flow backward into the fill pipe. The valve is cheap, and not hard to install.

So why doesn't TM do this when the build the trailer? The problem is that, with the anti-backflow valve in place, the water heater can't drain backward through the fill pipe. If you are draining down for cold weather, you have to remove the anode rod to drain the heater, and that is kind of a pain - and easy to forget. A full water heater will freeze and burst, and that is a very big deal.

One of the outstanding advantages of the TM is that the water system will drain by gravity through the drain valves under the trailer. No need for a water heater bypass kit, no need to pull the anode rod. Installing an anti-backflow valve removes this advantage.

You are in LA, so it may not be a big deal for you, especially if you stay out of cold places - in the mountains, for example. But if you sell the trailer, don't forget to mention it to the buyer.

Bill

[BaconLover]

Thanks Bill! I had read some posts about the air space in the water heater, but I wasn’t sure that was what was going on here, so thank you for confirming that it’s normal.

As long as it’s normal, I’m not too worried about it - I was just afraid that I had screwed up my hot water heater somehow. I’m always worried about having no water in the tank while the heat is on, so any little hot water thing makes me concerned that I’ve messed up the water heater!