Testing is the only option if you want to determine whether or not one or both of them has failed.
Electric hot water heater thermostat test.
In this case testing the thermostat is a little bit of a technical task but not hard at all.
Structure of water heater.
An electric hot water heater has two thermostats controlling two separate heating elements one in the upper half of the tank one in the lower half.
An electric water heater uses one or two heating elements to heat the water inside the tank.
Remaining always on is the most common issue with electric water heaters.
Although most of the cases this scenario occurs for the power supply problems.
Electric water heater thermostats are a fairly simple devices that can fail from time to time.
To look for faults you will need to use a screwdriver.
Upper thermostat makes it possible for you to have cold water supply when you turn on the tap of hot water.
When a water heater no longer produces hot water.
Electric water heaters have one or two elements and each is controlled by a thermostat.
If you want to test a thermostat on an electric water heater you will also need to check the heating element.
Lower thermostat ensures that the hot water keeps coming and it does not turn cold when you turn on the hot water tap.
This is important especially as open and grounded heating elements result in inaccurate tests.
How to test water heater thermostat this case might happen for the defected thermostat.
You will also need to check the water heater thermostat with digital multimeter tools.
If the hot water heater is not working one of the thermostats may be bad.
The electric heater has a total of two thermostats each performing distinct functions.
How to test a water heater element with a multimeter.
When a lower heating element or thermostat fails the top thermostat and element will continue to heat water in the upper half of the tank but you will notice the hot water quickly runs out or is only lukewarm.
You can test them with the power off using an ohmmeter to measure resistance or with the power on using a voltmeter to measure voltage.
When an upper heating element or thermostat fails the entire water heater stops producing hot water.
Working of a thermostat.
In general there are three main components in an electric water heater.