Before you proceed further with the process of testing the heater thermostat take a screwdriver and the multimeter.
Test upper thermostat electric water heater.
Using the multimeter connections touch the top to legs at the same time.
The lower thermostat has only two terminals.
The structure of an electric water heater is pretty simple.
Touch one probe of the multimeter to each terminal on the lower thermostat.
To look for faults you will need to use a screwdriver.
The reading on the multimeter should be zero.
If you have a voltage stick you can use that as well.
If the water is hot enough at appointed temperature the meter won t show reading.
The upper thermostat has two functions.
Use the screwdriver to set the lower thermostat to the highest setting.
Start by checking the thermostat terminals for the supply of power.
While the other is found right on the bottom.
Leave the upper thermostat in the lowest setting and test the lower thermostat.
Your water heater usually has two elements and two thermostats.
This is important especially as open and grounded heating elements result in inaccurate tests.
However they do go bad and testing water heater thermostats is still required.
Connect the multimeter pin ends on point 1 2 as shown in the picture below.
To look at the faults in the upper thermostat you need to turn off the lower one.
If you want to test a thermostat on an electric water heater you will also need to check the heating element.
If you get the reading of 240v on terminal 1 and terminal 3 then the power is on but if you get no readings then the power is off.
Testing the water heater thermostat involves the checking of the heating element also.
The meter should read 0.
Test the water heater thermostat.
First it allows the upper element to heat the water in the top of the tank.
If the water is cold the multimeter will point near zero.
One should be sitting on the top of unit 1.
Check the power supply of the thermostat.
You will also need to check the water heater thermostat with digital multimeter tools.
When this water is hot enough it shuts the upper element off.
And when it comes to thermostats the device uses two of them generally.
