Testing water heater thermostats is important in locating water heater problems.
Test water heater element thermostat.
Common residential dual element water heaters are 240 volts.
You can find this information on the data tag on the side of the water heater.
How to test an electric hot water heater thermostat step 1.
When it goes bad you don t have any hot water at all.
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.
Turn the water heater circuit breaker off inside the main service panel.
This is when the upper thermostat has a problem.
Start by checking the thermostat terminals for the supply of power.
If the water is hot enough at appointed temperature the meter won t show reading.
To look for faults you will need to use a screwdriver.
Now sometimes you use the hot water tap to only discover cold water coming out.
Connect the multimeter pin ends on point 1 2 as shown in the picture below.
Before you proceed further with the process of testing the heater thermostat take a screwdriver and the multimeter.
Pull away any insulation that is.
If you want to test a thermostat on an electric water heater you will also need to check the heating element.
This article deals with thermostats on electric water heaters.
The upper thermostat controls both the upper and lower element.
Test the water heater thermostat testing the water heater thermostat involves the checking of the heating element also.
Both thermostats control two different heating elements for the heater to function.
If the data tag is missing you can identify single element vs dual element by the number of access panels on the water heater.
To look at the faults in the upper thermostat you need to turn off the lower one.
You can find the voltage written on the end of the heating element.
In this case also check the current at the high limit switch.
This is important especially as open and grounded heating elements result in inaccurate tests.
If the water is cold the multimeter will point near zero.
The access panels are on the side of.
You will also need to check the water heater thermostat with digital multimeter tools.
When shopping for a water heater thermostat you need to know how many elements the water heater has and the voltage.