F5
Pioneer Outdoor Discharge Pipe Temperature Sensor Fault

Indoor unit shows F5 and may stop during heating defrost cycles

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Open or shorted discharge pipe sensor, Sensor not properly attached to discharge line, Damaged sensor harness, Outdoor PCB sensor input failure

How to Fix / Troubleshooting

Safety first: Turn off power and allow the outdoor unit to cool before touching refrigerant lines; they can be extremely hot.

Steps to try:

  • Locate discharge sensor: This sensor is usually strapped to the small-diameter discharge line exiting the compressor.
  • Check mounting and insulation: Ensure the sensor is tightly attached and covered with insulation as originally installed.
  • Inspect wiring: Follow the sensor wires to the PCB, checking for damage or loose connectors.
  • Reconnect and test: Reseat the connector, restore power, and test operation.

When to call a pro: Persistent F5 after sensor replacement indicates an outdoor PCB issue.

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Repair Difficulty

Hard 4/5

Required Part

Compressor Discharge Temperature Sensor (NTC)
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