I have a few questions about an electric hot water heater. It's a 40 gallon
electric model with an upper and lower thermostat. It sits in the basement
and the facets that it's connected to haven't been used in a few years. I
wasn't getting any hot water when I turned the hot side of the faucet on, so
I took the inspection covers off the hot water heater. I pressed the reset
button and it pulled in and I can hear the unit working now.
The question I have is should I get 220 volts across the lower heating
element and lower thermostat when I check both screw terminals? I get 120
volts when I touch one and one side of the meter to ground. But when I check
both terminals I get nothing.
The upper thermostats and element read 220 volts when the meter is placed on
the pair of screws at the same time. Is the lower working right?
Only one heater element comes on at any given time. The top will come on
first, and not until it heats up and shuts off will it send power to the
bottom element. So, turn it on, you should have 220-240v across the top
element, nothing across the bottom element. Let it run a bit. After a short
period of time, the top of the tank will be hot, the upper thermostat shuts
off the upper element, and sends power to the bottom element. You will no
longer have anything across the top element, and you will have 220-240
across the bottom element. When the rest of the tank warms up, bottom
element shuts off, the entire tank is up to temperature.
The reason for this is for the top element to come on and quickly heat the
top of the tank. That way you get hot water quickly without having to wait
for the entire tank to heat up. I once did not understand this and thought
something was wrong with the thremostat, so I wired both elements to the top
thermostat. Fortunately, the breaker in the breaker panel quickly popped
before I burned the house down :(. I figured it out real fast.
And you would also have gotten 120 volts if you touched the OTHER end of
that element, because the thermostats in most electric water heaters are
single pole switches. The upper thermostat disconnected one side of the
220 volt line, but the other side was still connected to the lower element.
Typically, the upper thermostat has a sequencer. So that one
element is powered, or the other. But not both at the same time.
Sounds like the lower element is hot enough, and so it's heating
on the top element. Since you can turn off an element by breaking
one leg of the 220, it's very possible to read 120 volts to
Quite possible that your WH is just fine. What's the complaint?
Christopher A. Young
You can't shout down a troll.
Other than I was not getting any hot water, found the internal breaker in
the heater and reset it, nothing.
Then as inquiring minds want to know, is everything working correctly? That
was the reason for the questions, I obviously didn't understand how the
Ook and Jeff then explained to me that it's working correctly.
"Stormin Mormon" <email@example.com> wrote in message
The red button near the wh element is not a breaker. It's a heat
limit switch. Although it does break the ciruit, it does so on the
basis of high temp, not high current. Using the term breaker will
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.