Originally Posted by ilyaz
The only single-handle faucet was in the kitchen but it's not there anymore, just two pipes sticking out from the floor.
Not sure I understand you 3rd question. Can you give me an example?
By the way, what happens if the heater is never flushed/drained? We've had it for about 3 yrs and never performed any sort of maintenance on it.
I don't want to hijack this thread. I'm interested in Redwood's analysis of what's causing a gradual and steady cooling of the hot water in the shower (besides a bad dip tube). And, I could think of an example of the kind Ilyaz wanted, so I figured I'd speak up.
An example might be a shower head that allows you to turn off the water at the shower head temporarily to lather up. If someone were to do that, (to answer the phone, say) and then dried off and got dressed and never did shut off the water at the faucet, then there would be a direct connection between the hot and cold water supply piping via the shower valve. If that person then came home and turned on the lawn sprinkler, he could find that he's watering his lawn with hot water instead of cold water. In Plumber-ese, that kind of situation is called a "cross connection".
What Redwood is thinking is that you might have one of these cross connections in your house, and any cold water getting into the hot water supply piping would result in the shower gradually becoming cooler. (cuz then you have cold water coming in both the cold water and hot water supply piping into your shower valve)
What happens if you don't flush your water heater for three years?
That depends heavily on the hardness of your water.
Scale, or "lime" forms on the hottest surfaces when water is heated. This scale is formed from the hardness ions in the water precipitating out on hot surfaces. So, if you have hard water and you have a gas fired water heater, you can expect a lot of scale to form on the hot bottom of the enamel coated tank where the gas flame impinges. That scale insulates the water from the flame, and causes the metal bottom of the tank to get much hotter than it otherwise would, and that will increase the thermal shocking to the tank and shorten the life of the tank.
The same thing happens on the heating elements of an electric hot water heater. However, in that case, the heater can be drained and the heating elements removed and cleaned.
If you have soft water, then you get much less scale because most of the hardness ions have been taken out of the water before it reaches your house.
If you have soft water, you probably didn't do any harm at all to your water heater by not flushing it for 3 years. Truth be told, lotsa new home owners never flush their water heater. I had an A. O. Smith BTRC250 commercial water heater, and every time I'd flush it, the water would run clear right off the bat, so I eventually stopped bothering to flush it every month. The whole idea of flushing is to clean out any sediment or dirt accumulated at the bottom of the tank, but in my case, there was never any accumulated dirt to flush out.
If you do have any scale forming in your water heater, the tell tale sign is that your water heater will make funny (rumbling, popping or wheezing) noises when the main burner trays are firing. If you don't hear any funny noises like that when your water heater's main burner trays are firing, then I wouldn't be concerned.
Just start flushing your water heater every month from now on.