Eliwell E1

What does Eliwell E1 mean?

E1 indicates probe Pb1 (the thermostat/room temperature probe) has failed. The controller cannot read a valid temperature and switches to timed compressor control using the Ont and OFt duty-cycle parameters instead of regulation by measured temperature. The alarm icon stays on continuously until the fault is cleared.

Symptoms

• Display alternates between 'E1' and the set-point value.
• Alarm icon LED remains permanently on.
• Compressor runs on fixed duty-cycle timing rather than responding to actual temperature.
• Minimum and maximum temperature alarms are disabled.
• Buzzer activates if fitted.

Common causes

• Pb1 probe wiring is open-circuit (broken cable or loose terminal).
• Pb1 probe is short-circuited.
• Probe type parameter H00 is set to PTC when an NTC probe is connected, or vice versa.
• Measured temperature is outside the probe's operating range (–50 °C to +110 °C for NTC).
• Probe connector corroded or pulled from terminal block.

Diagnostic steps

1. 01

   Inspect probe wiring and terminals

   Power down the controller, then check Pb1 terminals for loose wires, corrosion, or visible cable damage. Re-seat connectors and torque terminals to the specified value.

2. 02

   Verify probe type parameter H00

   Enter the programming menu and confirm H00 matches the probe fitted: 0 = PTC, 1 = NTC. Change the setting if incorrect, then cycle controller power to apply the change.

3. 03

   Measure probe resistance

   Disconnect Pb1 and measure resistance with a multimeter at a known ambient temperature. An NTC probe should read approximately 10 kΩ at 25 °C; an open or shorted reading confirms a failed probe.

4. 04

   Replace probe Pb1

   Fit a new probe of the correct type and rating. NTC probes have no polarity; route the extension cable away from power wiring to avoid EMI interference.

5. 05

   Confirm alarm clears

   Power up the controller and verify the display returns to normal temperature reading and the alarm icon extinguishes.

When to call a professional

If replacing Pb1 and correcting H00 does not clear E1, the controller input circuit may be damaged. A qualified refrigeration technician should test the input voltage, verify wiring integrity against the panel schematic, and replace the controller module if the input remains unresponsive. Refrigeration systems operating on duty-cycle control without probe feedback can over-cool product, creating food-safety risk.