Water Heater Thermostat
If your looking for water heater thermostat information you can find
it all here. How to test or replace a thermostat. How to check the limit
switch, adjust the temperature, buyers guide and more.
Water heater thermostats are actually very simple devices. They
operate off of a bi metal switch located in the back of the thermostat.
When the bi medal disk reaches a certain temperature it will pop in or
out which ever the case may be and connect or disconnect the power
supply to the heating element. This bi metal disk is what you hear clicking
when the temperature is turned up or down.
Test a thermostat
How to check a thermostat with the power off. Thermostats can be tested with the power on
or off. You can check the voltage at the element to see if the thermostat is
working if your comfortable working with the power on.
Replace a thermostat
Replacing a thermostat is easy with this step by step guide.
No special tools required.
Water heater reset button
What to do if the reset button pops out.
How to reset your water heater limit switch.
Water heater temperature
How to adjust the temperature on a thermostat. What temperature should
your water heater be.
How to use a multimeter
How to read a multimeter to check continuity and voltage with an analog multimeter.
The thermostats in this pic are for a
duel element 240 volt storage water heater.
The thermostat on the left is the upper
or primary thermostat.
The thermostat on the right is the lower
or secondary thermostat.
The upper thermostat is mounted onto
a limit switch.
I have separated the limit switch and
thermostat so you can see each one separately.
This limit switch (top of pic) has a red reset button
As you can see this thermostat is
Power enters the thermostat on the top
left terminal. When the thermostat calls
for heat power is sent to the lower left
terminal which energizes the upper element
When the thermostat is satisfied power
is then sent to the upper right terminal
and is transferred to the lower thermostat.
This is the lower thermostat.
Power is sent to the top terminal from
the upper thermostat.
If the thermostat calls for heat
power will be transferred to the bottom
terminal which will energize the
The thermostat on the right is
designed for a single element
The thermostat on the left is
designed for a duel element water heater.
As you can see the single element
thermostat only has two terminals.
Power comes into the top terminal
from the upper thermostat.
When this thermostat calls for heat
power is transfered to the lower terminal
which energizes the lower element.
If your shopping for a water heater thermostat the two things you'll
need to know are the number of elements in the water heater and the
voltage of the water heater ( check the label on your water heater).
If the label is missing from your water heater you can find the
voltage written on the end of the water heater element.
The upper thermostat and limit switch are always sold together.
There are several brands of residential tank type electric water heaters.
You do not have to buy a brand specify thermostat.
If you must replace a thermostat its always a good idea to replace
both thermostats at the same time.
The links above go to Amazon.com. I use Amazon and recommend them
If you click one of the links and make a purchase, I will receive a small commission
which I use to keep this site up and to keep building pages.
Thanks for visiting.
Return from water heater thermostat to water heater repair guide home