Hot water heater - sometimes hot, sometime cold.

[ouchmythumb]

Hi guys,

I have an A O Smith Permaglas energy saver water heater.
A few days ago my hot water got very hot, much hotter than normal. I thought it odd but didn't worry about it. Then yesterday it went cold. I tested the voltage at the input and it was 240V, I opened the panel and hit the reset button and did not hear the slight noise I usually hear when the elements get hot. I adjusted the heat higher and then lower and heard nothing. The water remained cold all day. Today it was hot again and now it is cold once again. My guess is that the thermostat is bad but I don't know anything about water heaters. Anyone have advice on how to trouble shoot this thing and where to buy a new t-stat, if that is the problem.

Also can someone tell me were to look for serial numbers/model numbers or some such on this thing? I don't see anything around the access panel and I don't want to remove the fiberglass wrap if I don't have to.

[BOA]

Turn off the power and check the element(s) for continuity using the ohms setting. Hope This is not too late...

[ouchmythumb]

Hi BOA,

Not too late, I've been out for a few weeks.

The bottom element reads 13.5 Ohms. The top element reads 1 on the same setting. I think it is probably bad.

Do you suppose that would cause the symptoms I have been seeing? Recently I have had hot water but currently I have cool water, I can shower in it but it isn't fun.

I took off the insulation and found the specs:

I have a
A. O. Smith
model EES 52 913
50 gallon electric water heater.

[ouchmythumb]

I went to Home Depot and discovered that I can replace both elements and both thermostats for $30. I generally try to understand the problem and just fix what is broken but the whole thing is at least 15 years old and the parts are so inexpensive I might as well just replace everything and not bother trying to pin down what part went bad.

Thanks all.

[Phelps]

It's usually the bottom thermostat only, when this happens. They work more often as that its closer to where the cold water keeps entering the water heater. There is points inside. I often take suspected bad ones apart to inspect and see and confirm. I do that with almost everything I replace in anything, whether furnace/water heater control boards or whatever. I always like to see.

Inside are a set of points like the older cars had, or Square D well pressure switches have. They get pitted. They can glue themselves together and the spring associated with how the 'stat functions does not release the points from each other, due to this arc-welded like condition, and the water heater gets hot to where it steams more and you might not even be able to hardly touch metal faucet handles or spout. Sometimes the pressure relief valve trips open because of this. Then it goes cold after that because what often happens is the reset button (round red button) on the top thermostat can trip out.

[ouchmythumb]

I drained the tank and discovered that the top element was badly damaged. The bottom element looked fine but I already had the new one so I replaced it as well. I filled the tank back up, turned it on and I have hot water, brown but hot and the brown went away after a while.

Draining the tank was a job. I suspect that some sort of mineral crud had precipitated out and plugged the drain. I blew some water back into the drain and that cleared it up a bit but it still took a long time to drain. Once the level was below the top element I pulled it and used a siphon to get the rest of the water out, that went a lot faster.

I will hang on to the t-stats for a while, so far things seem to be ok without replacing them but I will look the old ones over and it they look bad I will replace them.

[Fischer]

If you're still getting brown water, you probably have a ton of sediment in the bottom of the tank. You'll notice brown most apparently when you fill your bathtub.

Cure:

Turn off the power.

Shut the water off

Take off your cold water flex connector on the top of the tank
Make sure there's a down tube intact (plastic tube extending into the tank from the cold water inlet directing incoming water to bottom of tank.
Drain the tank (you can speed this up considerably by using an air compressor at about 40psi and connected into the cold water inlet. You can hook up a quick disconnect from a 3/4 galvanized nipple to a 3/4 x 3/8" reducer. When you attach the quick disconnect don't jam it in, let it slowly charge itself to 40 psi)

When the tank is empty connect the cold water up again, turn on and let the water blast the bottom of the tank, fill maybe 1/10 full.

Shut it off-let it drain and repeat 3 or 4 times.

Make sure you drain all your other fixtures at the same time to flush the system.