Some water heaters will alert you if the reset button is tripped—a buzzer or beeper may go off when it happens. With some models, you will realize the switch has been tripped the next time you take a shower when you only have cold water available.
There are many reasons why your water heater trips the reset button. The primary reason is that the tank is overheating. The water overheating can cause serious problems including increased pressure inside the tank, scalding temperatures for water at the tap, and damage to the anode rod. Here we get to the bottom of specific reasons that the reset button may become tripped.
If you have a gas-powered water heater, it will have only one thermostat, which will usually be located near the base of the tank. If you have an electric water heater, it will often have two thermostats, one at the bottom of the tank and the second just above the midway point on the tank. If one or both thermostats have gone bad or is about to fail, that can trip the reset button.
Most commonly, when a thermostat fails, it becomes stuck in the on position, causing the tank's water to continue heating past the indicated temperature. This presents a severe hazard if it is not stopped, which is why the reset button trips—to protect the water heater from becoming damaged.
Problems with Heating Element
Your water heater will have as many heating elements as it does thermostats. If one of them develops a short in the wiring, it could result in an unsafe arc of electricity. The electricity arc can cause the heating element to receive power when it otherwise should not, which could eventually cause the water to become overheated. This situation will also prompt the reset button to trip.
Issues With the Emergency Cut Off (ECO) Switch
An emergency cut off (ECO) switch is the part of your water that turns off the water heater during an emergency. If the ECO switch has failed, either from spontaneous failure or from multiple incidents of overheating, it will activate automatically, to prevent a problem (that may not be real) and trip the reset button. A failed ECO switch will not cause the water heater to overheat by itself.
If all of the above are working correctly, it is possible that there is bad wiring somewhere in the water heater. This faulty wiring could be causing the water to overheat and then trip the reset button. This problem will require a professional plumber's intervention to find the problem wiring and replace it.
Reset Button Problems
If none of the above are the problem, the reset button itself could be faulty and trip when not needed. This can also cause a feedback problem to the ECO switch. It can sometimes be challenging to know the exact cause of a tripped reset, so it is usually helpful to consult with a professional plumber about it.
In general, if the reset button gets tripped once, just reset it. Not all issues with the reset are dangerous, expensive, or concerning. Sometimes, a power surge can even trigger the reboot. However, if it is a continual problem, you will need to contact a professional plumber to diagnose and fix the problem.