Water Heater Troubleshooting

[ronaldrc]

Water heaters and troubleshooting them. I thought this little bit of information might help
someone down the road.

I have been in the Electrical trade for around 40 years, Yes I am old! And most of
this time has been troubleshooting.

Have you never been called to check a water heater and the problem is the overload
cutout is popping out on the upper thermostat? Well this is a common problem and is
usually caused from a thermostat stuck in the closed position the heating elements is
shorted to the case of the heater and the thermostat can?t cut it off ,or thick sludge has
coated around the upper thermostat.

Once I fixed one with this problem and I seen the customer a few months later and
they told me they had to replace the heater because they had another electrician to work
on it and it still did the same thing.I didn?t ask them why they didn?t called me back. I
was afraid of the answer. ?The other electrician replaced the thermostat too.?

But anyway I was called the other day for the same thing the overload was popping
out on a customers water heater.

Checked the heater elements around 13.5 ohms between the terminals on both.
Checked the elements to ground with a high resistance ohm meter to ground they
where both clear.

Checked thermostats with a ohm meter and turned the set screws back and forth to
make sure they where switching on and off right, they checked good.

And as I was getting ready to tell the customer all the electrical checks out and there
must be sludge around the upper element it donned on me that there was something
funny when I turned the upper thermostat up and down .And what it was , the element
was becoming energized when I turned the set screw counterclock wise.

Not really thinking about it all I was interested in was that the stat was switching back and
forth between the two terminal screws.

The person that had put the thermostat in had put the upper thermostat wire where the
lower thermostat wire should be and the lower wire where the upper should be.
And if you examine this circuit with the elements reversed the electrical power is never
shut off to the upper element. So the cutout has no choice it will pop out if working
properly.
Then it donned on me this was probably what was wrong with the heater I mentioned
above.It is easy not to pick up on this so check for this.

Everyone have a Merry Christmas and a great New Year.

 

[bkludecke]

Thanks for the tip. We troubleshoot electric water heaters all the time and it never hurts to have another "arrow in the ol' quiver"

One of my favorite tricks is replacing the lower element w/o draining the tank. If the tank is so choked w/sediments that the lower element overheats and fails it is usually best to r&r the tank. Sometimes though, the h/o is either unwilling or unable to pay the price and a new element may buy another year or two. Problem is, the sediment may prevent draining the tank to replace the element; sooo. We take a large towel or blanket and put it at the bottom of the tank, make sure ALL water valves are closed (off), get the new element ready to go, unscrew the old element almost all the way, say a prayer, pull the old element HARD (best to be wearing gloves), and shove in the new one ASAP. With the valves off very little water is lost to the towel and you are done in minutes. It's scary the 1st couple of times & then it's just SOP.

 

[Bob NH]

I also watch a plumbing board www.terrylove.com. The SOP for plumbers facing electric water heater problems is drain the sludge by connecting a hose to the drain and running water through it until clear. Then replace both elements and both controls. The customer feels good when he sees all of that sludge from the tank, and feels good about all of the electrical parts replaced.

A burned out lower element is almost always a sign of excessive sludge in the bottom of the tank.

If the heater is past warranty period, they recommend replacing the heater, which is probably more than an electrician wants to do.

From my experience, there is always a risk of replacing elements because the tank can be corroded enough that breaking loose the element can break loose enough rust that you can't get the new element to seal.

 

[bkludecke]

Yeah we've seen that too.

 

[mdshunk]

From my experience, there is always a risk of replacing elements because the tank can be corroded enough that breaking loose the element can break loose enough rust that you can't get the new element to seal.

Years back, many water heaters had elements with square flanges, and 4 bolts (one in each corner). On a very old water heater, you were lucky if you got all four bolts out without snapping one off. I quit changing the 4-bolt elements, because of that. I havn't seen an element of that style in a very long time. They pretty much all screw into a bung now, but there's a couple of new sizes of bungs nowadays. Joy.

I notice that it's mostly older folks call me to fix electric water heaters. That must have been the electrician's A.O. in times of old. Older folks call me to fix lamps and small kitchen appliances on a semi-regular basis also. I'll do the lamps (heck, I keep a good many lamp parts on the trucks), but they can get someone else to fix the toaster.

 

[LarryFine]

One of my favorite tricks is replacing the lower element w/o draining the tank.
We take a large towel or blanket and put it at the bottom of the tank, make sure ALL water valves are closed (off), get the new element ready to go, unscrew the old element almost all the way, say a prayer, pull the old element HARD (best to be wearing gloves), and shove in the new one ASAP. With the valves off very little water is lost to the towel and you are done in minutes. It's scary the 1st couple of times & then it's just SOP.

Great tip. I just did both elements in one about a week ago. I lost maybe a cup of water from both, total.

I made a funnel from aluminum foil, one end tucked under the 'bung' and shaped to keep the insulation dry, and the other end shaped into a spout and into a shallow aluminum baking pan.

It seems the more you try to do it fast, the harder it is to get the new element started. Just go casually, and it's quick and easy.

 

[bkludecke]

Oh yeah, and I always keep a plug of duct seal handy just in case.