Heat traps and lack of hot water

Q: I found your Web site after reading an article in the Family Handyman and I wanted to thank you for the time and effort it took in putting it together. I will immediatly replace the drain valve on my year-old gas heater. I wondered about another problem. A friend has told me that my heater could be siphoning and that would explain why I seem to run out of hot water quickly. He said it had to to with hot water rising on the cold water side of the heater. Sure enough: my cold water pipe was hot to the touch above the shut-off valve. Any idea what is going on and how I could fix it?

A: Well, you have two issues here. Heat rises, and so does hot water, so when your tank has been unused for awhile, the hottest water is at the top, and it will also rise into the plumbing. If your tank is plumbed with flex lines, you can remove them and put in longer ones, creating a heat trap by putting a big gooseneck in the line. Then you insulate the pipe. The heat won't go beyond the trap and the insulation will keep you from losing energy. However, I doubt that has much to do with your lack of hot water. One possibility is that you have high-flow showerheads. Changing to low-flow will help. Another is that your dip tube is broken or missing, as described in the Handyman article. A third is that your expectations are simply greater than your tank's capacity. You can run a typical 40-gallon out in 10-15 minutes, even with low-flow heads. Then you have to start thinking about a bigger tank or one with a higher recovery rate. (1995-2000)

Ins and outs of heat traps

Q: I see on the Rheem web site that they sell heat trap fittings that are for the hot and cold water sides of the heater. They look like check valves. I know you have something about a heat trap "loop" and was wondering what are the advantages/disadvantages of these fittings. Thanks, Jim

A: Their primary disadvantage is that they rattle. It's especially bad if you have a recirc loop that keeps water moving. Piping does an astonishingly good job of broadcasting water heater noise. Even if the water heater is at one end of the house and you're at the other, you'll be able to clearly hear the noise, especially at night, when it can be enough to keep you awake. -- Randy Schuyler

A1: Hello: There is a new type of heat trap fitting on the market that is simply a rubber flap in the pipe. When water flows, the flap is pushed aside. The advantages are that it's quiet and small. Whether it does much good (not a tight seal) or will last long are unknown. The advantages of a loop are that there are no moving parts or flow restriction. It does need to be insulated to perform well. The ball type check valve was/is an ongoing source of complaints. -- Larry Weingarten (2/03/05)