How to Fix / Troubleshooting

Safety: Risk of scalding. Turn OFF power and allow the unit to cool before working on it.

Corrective steps:

Check the temperature setpoint on the display and reduce it to a safe level (e.g., 120°F / 49°C).
Remove the cover and inspect the outlet thermistor and wiring. Ensure it is firmly attached to the outlet pipe or heat exchanger and wiring is intact.
Descale the heat exchanger and elements if there is evidence of scale buildup, which can cause localized overheating.
Test the outlet thermistor resistance and replace it if readings are out of specification.
If the unit still overshoots temperature, the control board may be failing to modulate the elements correctly and should be replaced.

After repairs, verify outlet temperature with a thermometer at a nearby faucet to ensure safe operation.

Display shows E13; unit may limit output temperature or shut down.

Possible Causes