Do you often face problems with your water heater (Geyser) and not know what is the exact reason for that? Well, it is quite a common scenario with all us and most of the people often suffer from this problem. If you have tried every solution with your water heater but still couldn't find the accurate result, then maybe you should check and look its thermostat.

Yes, even a minor problem in the water heater thermostat can hinder the normal working of the appliance. Though, most of the people are not aware of this issue but hey, you just found one of the possible reasons for your faulty water heater.

Basic details of the water heater thermostat:

A water heater has 2 thermostats – the upper thermostat and the lower thermostat. Both the thermostats play a crucial role in the proper working of the water heater. If any of the thermostats fail, then your water heater may not perform in its expected manner.

Now, if you are wondering how the 2 thermostats affect the working of the water heater, then let us have a look at the same.

If the upper thermostat goes bad or faulty, then you will not get any hot water and it interrupts the suitable functioning of the water heater
However, if the lower thermostat goes faulty, then the flow of hot water becomes very slow or less. 

Though, there are lesser chances that the water heater thermostat will get faulty but it is not advisable to take any risks. Therefore, it is recommended to keep a check on the thermostat to determine which of the 2 is a faulty one and thus ultimately to replace it. 

Testing the water heater thermostat:

For the effective and suitable working of the water heater, it is necessary to check the water heater thermostat after regular interval of time. Now, if you are thinking that checking the thermostat would be a difficult task, then to your surprise it is not that difficult and can be easily done.

It is quite very easy to test the water heater thermostat for its effective working. Read along to find the needed steps to properly check the thermostat in the best possible manner.

a) Testing the upper thermostat of the water heater:

These are the following steps that you need to follow for checking the upper part of the water heater:

1. Make sure that the main power of the water heater is switched off
2. Once you are okay with this, then move towards removing both the access panels along with the insulin covers
3. In the next step, you should also remove the plastic covers available 
4. Before moving to any other step, you should make sure that the reset button of the water heater is not tripped. If this is the case, then you should first sort this out
5. Now make use of a small screwdriver and adjust the temperature of the upper thermostat to the highest level. Along with this, adjust the setting of the lower thermostat and keep it to the minimum level.
6. Now, turn on the power of the water heater. As soon as you do it, make sure that both the wires above the reset button are receiving voltage. If you see voltage coming to both the wires, this means that all the connections of the water heater are stable and are good to go
7. In the next step, place the probes of multi-meter on the contact screws of the upper element. Post doing this:

If you do not have power at the particular element, then the upper thermostat is faulty and thus needs replacement
But, if you have power at the upper thermostat, then it is the time to check and test the lower thermostat

b) Testing the lower thermostat of the water heater:

These are the steps that you need to follow for testing the lower thermostat:

1. Adjust the temperature of the upper thermostat to the lowest value
2. As soon as you do that, you should hear the click off sound from the thermostat. If you do not hear any such sound, then you should wait for some time and let the water heat a little and then should continue with the remaining process
3. Now adjust the temperature of the lower thermostat to the highest level
4. Use one probe of the multi-meter on the top contact screw and put the other probe on the water tank. After doing this,

If you are not getting reading, then replace the upper thermostat as it is not able to send the reading to the lower thermostat
But, if you have a reading and power, then move to the next step

5. Put one meter probe on the lower contact screw while putting the other probe on the water tank. After doing this,

If you are getting reading, then the lower thermostat is in good condition and does not require any replacement
However, if there is no reading, then the lower thermostat is faulty and it should be replaced

These are some of the easy and quick steps that you can follow for testing the thermostats available in the water heater. If needed, you can always take the help of an expert professional for testing and then replacing the thermostats.


Checking on the thermostats of the water heater is one of the most essential needs that you should fulfill at a regular interval. It can be quite risky to avoid keeping a check on the thermostat of the water heater. Also, with the regular checking and testing of the thermostat, you can enhance the lifeline of the water heater and thus can get its benefits for the maximum time.

If you need any other information or detail about the testing of the water heater thermostat, then please do comment below and contact us. We are always ready to help our readers, in the best possible manner, with the best information that we have.