P8 Pipe temperature out of range (coil not cooling or heating)

What the control is telling you

The coil temperature does not move far enough from room temperature: in cooling the coil must be at least 3°C below the return air, in heating at least 3°C above. It takes at least 9 minutes (cooling) or 27 minutes (heating) to detect. Not checked in dry mode or during defrost.

Applies to: PEAD-RP35/50/60/71/100/125/140JA and JA(L) ducted indoor units (220-240 V models)

Likely causes

• Low refrigerant charge
• Pipe sensor holder loose on the pipe
• Refrigerant circuit fault
• On multi-unit systems: line sets crossed between units
• On multi-unit systems: indoor/outdoor wires crossed between units
• Room or pipe sensor reading wrong
• Service valves not fully open

Test and repair steps

1. Make sure both service valves on the outdoor unit are fully open.
2. Check that the TH2 and TH5 sensors are clipped tightly to the pipe.
3. Compare room and pipe temperatures on the remote (or with the outdoor A-Control service tool) with real readings.
4. Check the refrigerant charge and look for leaks.
5. On twin/triple or multiple systems, confirm each line set and S1-S2-S3 wire goes to the matching indoor unit.
6. After the repair, cycle the power and run the unit to confirm the code does not come back.

Models that show this code

14 models in Mr. Slim PEAD-RP JA(L) ducted indoor unit

Other codes on the same units

• P1 Room (intake) air sensor TH1 open or shorted
• P2 Liquid pipe sensor TH2 open or shorted
• P4 Drain float switch disconnected
• P5 Drain overflow - float switch wet with pump running
• P6 Coil freeze or overheat protection
• P9 Coil sensor TH5 open or shorted
• Fb Indoor control board memory error
• PA Water leak detected