AO Smith electric water heater keeps shutting off, e02

[mike4500]

Model Number

50 g

Brand

-brand-

Age

1-5 years

I have an AO Smith 50 gallon with the electronic display. I initially had to replace the lower element due to limescale. Once I did that and cleaned out the sediment, I had an e02 error code on the panel. I replaced the upper element, and then replaced the thermostat as tech support said that might be causing the problem. I am still getting the error code. I unplugged the electronic panel, and the unit functions for a few hours when I turn off the breaker, wait several minutes then turn it on again. However, a few hours later I get the blinking red light (2 flashes) and the unit stops heating water. The red high limit button is NOT tripped. I have tested the power at the thermostat and the elements with a multi meter and they all check out fine.

Any thoughts? I am at a loss.

 

[Jake]

It sounds like the main control is malfunctioning, what's the complete model number of this water heater?

Jake

 

[mike4500]

ES12-50R55DV 110

 

[Jake]

Thanks,

I'd override the ESM first and see if the ESM is the culprit.

--->Overriding The Energy Smart® Module (ESM) If the Energy Smart® Module (ESM) is not working: Simply unplug the interface module and turn the set point knob on the Electronic Thermostat (ET) to the desired temperature (See Figures 9 & 10).

To replace a broken or damaged ESM module, see page 36 for ordering information.

Jake

 

[mike4500]

No, it's not. I had already unplugged the ESM and the problem persists. A little more information....sometimes when I shut off power at the breaker, let is sit for a while and then turn the power back on, it will do it's diagnostic cycle (blinking green light) and then start flashing red (2 times). But then sometime later it will start to heat the water and the green light will begin flashing rapidly. It may stay that way for a few hours but eventually the heater shuts off and the light flashes red (2 times) again.

I'm thinking maybe a short somewhere? Not sure how to test for that though.

 

[Jake]

Possibly a short somewhere, check all your wires for frayed or cut insulation on them shorting out.

Jake

 

[mike4500]

I checked all the wires and didn't find any problems, frayed insulation, etc. However, there is a four pin white plug in the water heaters junction box that I believe is the connector for the smart grid module, and two of the wires have come out of the pin/connector. I don't think this would have an effect like I am seeing though, and I never connected a smart grid module to the heater.

What I don't understand is why the unit keeps giving me a high temp limit code when it isn't heating up in the first place and the red reset button never "pops.".

 

[Jake]

Ok, yes I really don't know, I rarely service these newer water heaters, so your best bet is to Contact AO Smith again to see what's going on.

Jake

 

[Josh R]

I checked all the wires and didn't find any problems, frayed insulation, etc. However, there is a four pin white plug in the water heaters junction box that I believe is the connector for the smart grid module, and two of the wires have come out of the pin/connector. I don't think this would have an effect like I am seeing though, and I never connected a smart grid module to the heater.

What I don't understand is why the unit keeps giving me a high temp limit code when it isn't heating up in the first place and the red reset button never "pops.".

Did you figure out what it was?

 

[mike4500]

I eventually called an electrician, who said it seemed to be a short at the top of the tank where the wires for the power and smart module are. He said it appeared the thin wires for the smart module had burned out from the plastic connector. I called AO Smith and told them, they had me send them some photos of the area, and then they authorized a replacement. So not happy that I had to replace it, but very happy with AO Smith that they honored the warranty. I replaced it with another AO Smith model, but a more base model without the smart module option. Less things to go wrong. No problems with the new one, plus it was much cheaper and lowes gave me a credit for the old one, not just a straight replacement, so I ended up with a lowes gift card for the difference.