Indoor unit displays F1 and the unit may run with poor performance or shut down.

Safety first: Turn off power before accessing the indoor coil and PCB.

• Step 1 – Check sensor mounting:
  • Locate the evaporator sensor clipped to the coil.
  • Ensure it is firmly attached and not hanging loose.
• Step 2 – Inspect wiring:
  • Look for pinched or rubbed-through insulation where the sensor wires pass through metal.
  • Secure loose wires with cable ties to prevent vibration damage.
• Step 3 – Replace sensor if suspect:
  • If the unit is older or the sensor shows signs of discoloration or cracking, replace it with a Hisense-compatible T1 sensor.
• Step 4 – PCB evaluation: If a new sensor does not resolve F1, the indoor PCB may be misreading the sensor and should be tested or replaced by a technician.