Eldom digital water heater shows E05; temperature reading is unrealistic (e.g., - - or 99°C constantly).

Safety: Turn off power before removing covers or touching wiring.

Steps:

• Verify sensor placement: Remove the cover and locate the NTC probe. Ensure it is fully inserted into its thermowell on the tank and secured with its clip or bracket.
• Check sensor type: If the sensor was recently replaced, confirm that a correct Eldom-compatible NTC (same resistance curve) was used. Using a generic sensor with different characteristics can trigger E05.
• Measure resistance vs. temperature: At room temperature, measure the NTC resistance and compare with Eldom specifications (often ~10 kΩ at 25°C). If the reading is far off, replace the sensor.
• Inspect wiring: Look for damaged insulation or moisture on the sensor cable and connector. Dry any condensation and reseat connectors.
• Control board check: If a known-good sensor still gives E05, the analog input on the control PCB may be defective and the board will need replacement.