E3 error on gas model, ECO (energy cut off) or high limit opened, burner will not light

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Overheating due to scaled tank, thermostat failure, gas control valve internal fault, restricted water flow

Safety first: Turn OFF gas and power. Allow the heater to cool.

Checks:

Inspect for signs of boiling or rumbling noises indicating heavy scale.
Verify water flow through hot outlets is normal (no severe restriction).
On some models, the ECO is non-resettable and integrated into the gas control valve; if tripped, the valve must be replaced.

Corrective actions:

Flush the tank to remove sediment and scale.
Replace the gas control valve/thermostat assembly if ECO has opened and cannot be reset.

Warning: Do not attempt to bypass ECO or high-limit devices.

Hard 4/5

Gas Control Valve / Thermostat

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