How do I reset an electric water heater?

Use these points to understand the procedure in your model's manual. Do not open electrical covers unless you can safely isolate and verify power. If the high-limit control tripped, have the cause investigated and corrected before return to service, as Rheem requires in the cited manual.

1. 1Turn off the breaker for the water heater. A. O. Smith warns that circuit breakers can be mismarked, so check the incoming power wires with a voltmeter before you touch anything. If you can't do that, leave the panel on.
2. 2Let a hot tank cool. Lennox says that if the unit has been overheating, give it time to reach a safe temperature before you begin any inspection or reset attempt.
3. 3Locate the control using the model's instructions. A conventional tank may place it behind an upper access panel and insulation; an electronic model can use a different cover or power board. The cited Bradford White procedure is for its commercial electric units, so do not assume it describes your residential heater.
4. 4Identify the specified reset control. On some conventional tanks it is a red button on the thermostat. Confirm the location from the rating plate, wiring label and manual instead of guessing from the color.
5. 5Reset only as the manufacturer directs. A click can show that a manual control reset, but it does not establish that the overheating cause is gone. Do not bypass the high-limit control.
6. 6Restore all covers before service resumes. Put insulation, protective covers and access panels back as the manual shows. Restore power only after the overheating cause has been investigated and corrected and the tank is completely full.
7. 7Allow the model's recovery time. Heating time depends on tank size, element rating, inlet temperature and use. Watch for another trip or signs of overheating rather than treating a fixed wait as a successful repair.

Those are the safety boundaries. The model's manual supplies the actual procedure, and a technician should handle electrical diagnosis or an unexplained high-limit trip.

### How do I know the button tripped?

Lennox lists a few signs that a reset may be needed: no hot water or suddenly cold water, a heater that is not heating after a power outage, an electric heater that stopped working unexpectedly, and a reset button that has visibly popped out. It also says that when the button is out of its normal position, the system has been triggered and needs attention.

The button belongs to the high-limit control, often called the ECO, short for energy cut off. Rheem describes it as a temperature limiting control above the upper heating element, in contact with the tank surface. If the water temperature becomes excessively high, it breaks the power circuit to the heating element. Rheem also says: "Once the control opens, it must be reset manually."

A. O. Smith's troubleshooting chart puts the click to use: if the button clicks, the water heater got too hot and tripped the energy cut off. A click means the safety did its job. It does not tell you why the tank overheated.

### Why would the water get too hot in the first place?

Bradford White's service manual gives one clear route. A heating element with a short circuit to ground will in most cases cause the circuit breaker in the service panel to open. In some cases there may not be enough current draw for the breaker to open, and the element can then run continuously, which overheats the water. The ECO is what limits it.

### What if the button does not click?

Then the ECO probably was not the problem. A. O. Smith's chart says that if the energy cut off did not trip, the next step is checking the upper heating element, and if the upper element is good, replacing the upper thermostat. The chart also starts by checking for power at the top two screws of the upper thermostat, and if 240 volts is not present, checking the circuit breaker and wiring. That is live electrical work, so it belongs to a technician or a confident electrician. Our page on how to test a water heater heating element covers the meter checks with the power off.

Check the breaker panel first. Rheem's troubleshooting chart lists a blown fuse or tripped circuit breaker and a tripped manual reset limit (the ECO) as separate causes of no or little hot water. They are two different resets. If the breaker itself keeps tripping, that is a different problem from a tripped ECO. See why an electric water heater keeps tripping the breaker.

Not every tank resets the same way. Rheem's manual for its e-control electric models has another route: turn off the power, remove the user interface control and insulation, press the red RESET button on the power board and upper sensor assembly, then put the insulation and control back before turning the power on. Your model's manual, or the label on the tank, shows the right path. This walkthrough is for tank heaters, not tankless.

Gas tanks are a different job entirely. The reset there is a thermal switch behind the burner door, and the checks around it involve venting and gas. See where the reset button is on a gas water heater.

If the button trips again, stop pressing it and have the heater checked. Lennox says repeatedly pressing the reset button without addressing the root cause can make the problem worse over time, and it lists repeated tripping of the button or breaker as a reason to bring in a professional. It also lists a burning smell or unusual noises as signs that need attention right away.

Rheem is direct about why: "The cause of the high temperature condition must be investigated by qualified service technician and corrective action must be taken before placing the water heater in service again."

Bradford White's service manual says repeated actuation of the ECO reset button on the thermostat usually is the result of a grounded element. A. O. Smith's chart adds that if both elements test good, the thermostat contacts probably welded shut, causing the element to be on all the time, and it calls for replacing the thermostat.

Lennox's list of common causes when the reset button trips repeatedly includes a faulty or shorted heating element, a malfunctioning thermostat, loose, damaged or corroded wiring, an electrical short circuit within the unit, an undersized or failing circuit breaker, and water leaks affecting electrical components.

Two more cases call for stopping. If the heater has been through a flood, fire or physical damage, Rheem says to turn off power and water and not operate it again until qualified service personnel have thoroughly checked it. And after any element replacement, Bradford White says to be sure the tank is full of water before you energize the water heater.

### What should I tell the technician?

A few details save time. Say whether the button clicked, how long the heater ran between trips, whether the breaker tripped too, and whether there was any burning smell or noise. Take a photo of the rating plate. If the heater is old and the trips keep coming back, our page on why you might have no hot water covers the other failures to expect.

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