Slight temperature difference between indoor room temperature and pipe temperature thermistor

What does P8 mean?

The P8 abnormality is detected when there is an insufficient temperature difference between the indoor room temperature (TH1) and the indoor pipe temperature (TH or TH) during cooling or heating operation. In cooling mode, the pipe temperature must be within the cooling range (TH_pipe - TH1 < -3°C) after 9 minutes. In heating mode, the condenser/evaporator pipe temperature (TH) must be within the heating range (TH_pipe - TH1 > 3°C) after 17 minutes. Potential root causes include refrigerant shortage, disconnected thermistor holder, defective refrigerant circuit, converse connection of extension pipes, or incomplete opening of stop valves.

• Difference between indoor ambient temperature sensor (e.g., P24) and pipe temperature sensor (e.g., P25) exceeds threshold.
• Poor insulation on piping.
• Faulty indoor room temperature sensor.
• Faulty pipe temperature thermistor.
• Incorrect sensor calibration.

Click steps to track your progress.

1. 1

   Using the remote controller and the outdoor controller circuit board, check the pipe (liquid or condenser/evaporator) temperature against the room temperature display. Set SW of the outdoor controller circuit board and connect an A-Control Service Tool (PAC-SK ST) to display the pipe temperatures.

2. 2

   Verify the connection of extension pipes for converse connection. Inspect the indoor/outdoor unit connecting wires for converse wiring.

3. 3

   Inspect the stop valve to ensure it is completely opened.

4. 4

   Check for refrigerant shortage or leakage in the refrigerant circuit.