crazy water heater? Hot water changes temp by itself!?

Question

Sometimes my hot water is only lukewarm, other times it is so hot I can't even wash my hair in the shower. It has been like this for as long as I've owned my home (4 years). When the water was scalding hot one time I turned it to a very low setting and that helps sometimes but the water still is acting up. It was really hot all the time for the last week until I turned it down yet again. what's going on?

Answer 1

You don't mention whether it is an electric or gas water heater, so we'll go through both. It's likely the thermostats, (2), that have gone crazy, theyt control the elements on an electric unit. They are located under a couple of metal covers, one towards to the top of the tank, the other near the bottom. They aren't hard to replace, just remember to shut of the electricity to the unit before doing any repairs, make a drawing showing which color wires go to which screws, then replace them on the new thermo the same way they came off the old one. Same goes for the top and bottom. If it's gas, then it gets more difficult. It would most likely be the gas control valve, which incorporates a thermostat into the back side of the valve. This would be the grey boxy looking thing near the bottom burner opening. The complete unit has to be replaced, which necessitates draining the tank, taking the gas burner, pilot and thermocouple lines loose from the bottom of the valve and then unscrewing it out of the side of the tank. You stated that it's been acting up for over four years, which means it's way out of warranty and the valve is a very expensive part. So if it's a gas unit, you may want to just replace the entire thing rather than try to get a new thermo/gas valve.

Answer 2

I understand the expected life time of a water heater is 10 years. You mentioned "a few years." It may simply be reaching the end of it's useful life. Having had problems like this, I'll tell you that you do NOT want that thing to rupture and empty the water where ever it is sitting. Get it checked by a professional or just go for replacement.