Atlantic electric water heater does not heat; control panel shows E1 shortly after power-up.

Safety first: Switch OFF the circuit breaker and verify no voltage at the heater terminals with a multimeter before opening any covers.

Steps:

• Remove the front plastic cover to access the electronic control module on the Atlantic heater.
• Locate the tank temperature sensor (NTC probe) usually inserted in a dry well near the bottom of the tank and connected to the control board with two small wires.
• Disconnect the sensor plug from the control board and measure its resistance with a multimeter. At room temperature (20–25°C), most Atlantic NTCs read between 8–15 kΩ (check the rating label or service manual if available).
• If the reading is infinite (open) or near 0 Ω (short), the sensor is defective. Replace it with an original Atlantic NTC temperature probe of the same value.
• Inspect the wiring harness from the sensor to the control board for cuts, burns, or loose connectors. Reseat the connector firmly on the board.
• If the sensor and wiring test good but E1 persists, the temperature input circuit on the Atlantic control board may be faulty and the board should be replaced.
• After replacement, restore power and run a heating cycle to confirm that the error is cleared and the water heats normally.