On the covered Kenmore hybrid gas water heater, E08 means Kenmore's service table lists this code as: energy Cut-Out (ECO) switch open. Check the inlet water filter and measure the water temperature. Let the tank cool and check the thermostat setting.
Differential
Likely causes of “Kenmore hybrid gas water heater code E08”, and how to tell them apart
- 1
The Energy Cut-Out switch has opened
What separates it The water heater shuts off and the display shows E08
How to confirm Check the inlet water filter and measure the water temperature
- 2
Water that has overheated
What separates it The tank water is hotter than the ECO opens at
How to confirm Let the tank cool and check the thermostat setting
- 3
An ECO switch that is stuck open
What separates it The water is below 149 degrees and the switch is open
How to confirm Check the switch with a multimeter
- 4
Open or disconnected wires in the ECO harness
What separates it Wires are loose
How to confirm Check the harness and connections
- 5
A control board that does not see the switch correctly
What separates it The switch and wiring are fine
How to confirm Replace the control board
Before you touch a setting
Record this first — changing settings destroys the evidence
- That the display shows E08
- The water temperature
- Whether the inlet water filter is clogged
- The model and serial numbers
Try in this order
0 of 10 completedCorrect only the documented fault domain
ReversibleThe control board detected the Energy Cut-Out (ECO) switch has opened and prevented power to the main valve. Check inlet water filter. Measure the water temperature. The ECO switch opens at 185 degrees Fahrenheit, plus or minus 14 degrees, and closes at temperature 149 degrees, plus or minus 14 degrees. Check the ECO switch with a multimeter to see if it's open or closed. Check the ECO wire harness and connections for any open or disconnected wires. If the ECO switch is open and the water temperature is below 149 degrees, replace the control board. Parts named: ECO switch, Control board.
Check the inlet water filter and measure the water temperature
ReversibleThe ECO switch opens at 185 degrees F, plus or minus 14, and closes at 149 degrees F, plus or minus 14; a clogged filter can let the tank overheat.
Check the ECO switch and its harness with a multimeter
ReversibleWith the cord unplugged, test the switch for open or closed and check the ECO wire harness and connections for open or disconnected wires.
Replace the control board if the switch is open and the water is cool
ReversibleThe chart says if the ECO switch is open and the water temperature is below 149 degrees F, replace the control board; it lists the ECO switch and the control board as the parts.
Check the inlet water filter
ReversibleA blocked filter can restrict flow and contribute to overheating.
Measure the water temperature
ReversibleThe ECO switch opens at 185 degrees Fahrenheit, plus or minus 14, and closes at 149, plus or minus 14.
Check the ECO switch with a multimeter
ReversibleSee whether it reads open or closed.
Check the harness
ReversibleLook for open or disconnected wires in the ECO harness.
Replace the control board
ReversibleIf the ECO switch is open and the water is below 149 degrees, the table says to replace the control board.
Test the heater
ReversibleRestore power and gas and watch that E08 does not return.
Model-specific
What is true of this model and not of its siblings
- The code on this page
- E08, the Energy Cut-Out switch is open.
- Parts involved
- The ECO switch, the harness, the inlet filter and the control board.
- Source
- Sears PartsDirect's table for Kenmore hybrid gas water heaters.
- What the ECO is for
- The Energy Cut-Out is a safety switch that opens if the tank water gets too hot. It cuts power to the main valve so that the heater cannot keep heating, and it closes again only when the water has cooled, which is why the temperatures in the table matter.
- Why the filter is checked first
- A blocked inlet water filter restricts flow into the heater and can let the water overheat. Cleaning it is cheap and quick, and it is the first check in the table before any part is replaced.
Stop boundary
When this stops being a self-service repair
- !Hot water above 149 degrees F can scald, so measure and handle it with care while you check the E08 fault
- !If the ECO switch is open and the water is below 149 degrees, replace the control board
- !Turn off the gas and the power before checking wiring
- !If you smell gas, leave the house and call the gas company
Evidence ledger
Sources behind this answer
Where the manufacturer's article stops. The switch temperatures, the filter check and the harness check are chart text; the scald caution and the gas leak advice are general safety guidance.
Exact questions
Common questions
What does E08 mean on a Kenmore hybrid gas water heater?+
Kenmore's service table lists this code as: energy Cut-Out (ECO) switch open.
At what temperature does the ECO switch open?+
185 degrees F, plus or minus 14; it closes at 149 degrees F, plus or minus 14.
Is the filter involved?+
Check the inlet water filter first.
When is the board at fault?+
When the switch is open and the water is below 149 degrees.
Can I bypass the ECO switch?+
No. It is a safety device that protects the tank, and bypassing it is dangerous.
What does a cool tank with an open switch mean?+
If the water is below 149 degrees and the ECO is still open, the switch or the control board is at fault, as the table says.