Water Heater Thermostat Upper Vs Lower

Use the water heater tester to check terminals 1 and 2 the lower set.

Water heater thermostat upper vs lower. Rarely do both thermostats fail at the same time although i do recommend replacing both when one fails. 1 turn off the circuit breaker to the water heater. The upper thermostat is different from the lower thermostat. When an electric hot water heater s elements short out or burn through cool water is the result.

But if the water is hot that becomes later becomes cold then you have a damaged lower thermostat. Normally it will not be able to keep the water hot but it will do the best it can depending on the water flow. It s not necessary that both thermostats will do the same work their work can vary according to the water heater unit. I m guessing that setting your top thermostat to a 150 would give you small amount of really hot water rather quickly while setting the upper and lower thermostats evenly to a moderate temperature 115 125 would be your quickest way to get a full tank of hot water.

Replace the upper thermostat. If you turn the hot water tap and cold water runs out then the upper thermostat is damaged. The reading should be between 110 and 120 volts. When an upper heating element or thermostat fails the entire water heater stops producing hot water.

Repeat the test with the other screw. Hj az circulation system or not the upper one only operates when the heater is almost out of water and the lower it is set the cooler the water will get before it turns on. They should be set the same but the lower one can be set a few degrees cooler if you feel better about that only one element works at a time the upper one works until the water temperature is reached in the upper half of the water heater then it switches to the bottom element to heat the lower half this keeps hot water flowing longer when it is being drawn for showers the lower element is. Most manufacturers recommend changing the lower thermostat setting while leaving the upper thermostat at the factory setting.

As soon as you complete this task you can fix it. This should insure that lower thermostat is allowed to engage. The upper thermostat is the primary one that contains the high limit switch and the lower thermostat is used to detect the change in the temperature of the water. The upper thermostat is larger and controls the lower thermostat.

To check the lower thermostat you need the upper thermostat turned off. The lower thermostat needs to be turned to its highest setting. However you will need to know how to test a water heater thermostat to find the faulty unit. Thermostat setting on dual element heater.