Hydraulic Indoor Unit LED2 (Green) 7 Flashes, LED1 (Red) 3 Flashes - Heat exchanger thermistor (outlet/intermediate) error

What does LED2 7 Flashes, LED1 3 Flashes mean?

This indicates a problem with the heat exchanger thermistor, which measures the temperature at the outlet or an intermediate point of the heat exchanger. The outdoor unit may also show '4 Flashes' for a heat-exchange thermistor (outlet) error after pressing the ENTER switch.

• Faulty thermistor sensor.
• Loose or damaged wiring to the thermistor.
• Fouling or blockage in the heat exchanger affecting temperature readings.

Click steps to track your progress.

1. 1

   Turn off the main power supply to the heat pump for 30 seconds, then turn it back on.

2. 2

   If the outdoor unit ERROR LED is blinking, press the ENTER switch to confirm the specific '4 Flashes' error code.

3. 3

   If the error persists, use the 'Reset HP' function (Line 6711) in the control system.

4. 4

   Contact a qualified service technician to inspect the heat exchanger and thermistor.