P3
Keystone Low Temperature Protection / Freeze Protection

Keystone portable air conditioner shows P3 and may not start the compressor.

Advertisements

Possible Causes

Evaporator coil too cold, low ambient temperature, restricted airflow, faulty evaporator sensor

How to Fix / Troubleshooting

Steps:

  • Check room temperature: Do not operate the unit in COOL mode if the room is below the minimum specified temperature.
  • Clean filter and coil: Ensure good airflow through the evaporator.
  • Allow thawing: If ice is present, unplug the unit and let it thaw completely.
  • Sensor check: If P3 appears frequently under normal conditions, test and replace the evaporator sensor.
Advertisements

Repair Difficulty

Easy 2/5

Required Part

Evaporator Temperature Sensor
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements