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Mario, Master Plumber
Category: Plumbing
Satisfied Customers: 815
Experience:  Master Plumber, Fire Sprinkler, and Jobbing Spec.
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I have an A. O. Smith ELJF-50 water heater in one of my rental

Customer Question

I have an A. O. Smith ELJF-50 water heater in one of my rental properties. It is a 240 volt dual element 50 gal low boy. I'm not sure if I'm setting the elements properly or if there is something else wrong. The water heats for several hours and then it just shuts off. I have to push the electrical rest button to get it going again. And then it works fine for several hours and then shuts off again. I have both the upper and lower elements set at the 90 degree setting for safety. What can I do to figure out what's wrong? I am not an electronics expert so I will need something pretty straight forward. I do have a multimeter so I can check for voltage, current and resistance.
Submitted: 8 years ago.
Category: Plumbing
Expert:  Mario replied 8 years ago.



you have a either a bad element or a bad stat


over time the elements build up scale and a false reading goes back to the stat triping the stat ( causing you to push the button )


or the stat can get week and trip on a false temp


i have found that replacing the elements and the ststs when this happens is the best thing to do the cost is only around 30 to 40 dollors and usualy easy to do if you have experience


if your electricty skills are week do not atempt this project if you are good and handy i can tell you how




if the heater is older then 10 years replace the heater you are out of warentee and you mey be better off putting the money towards a new heater

Mario and other Plumbing Specialists are ready to help you
Customer: replied 8 years ago.
Mario, thanks. Just a clarification. When you say stat you mean tmermostat, right? Where is it on a hot water heater? Is there a way to check which element is bad? I would hate to just replace both for no reason.
Expert:  Mario replied 8 years ago.

yes i mean thermostat


to test an element you must


1) shut off the power

2) with a tester comferm that the power is off

3) remove the wires from the element and then test continuity between the two legs of the element then re assyemble


your issue is not that it is bad in terms of its a blown element but you have a heavy calcum build up that that it wont shut off in time for the unit ot heat up right so you may get contunity from it