Perfect Aire mini split error code F5

Common causes

• The fan is blocked by ice, snow, leaves or debris.
• The motor bearings are worn or the motor has failed.
• The fan motor connector is loose or its wiring is damaged.
• The fan drive circuit on the outdoor board has failed.

How to fix it yourself

Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.

1. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.
2. Look at the outdoor unit: clear leaves, cottonwood fluff, snow or ice from the coil and make sure the fan can spin freely and nothing is stacked against the cabinet.
3. With power off, spin the outdoor fan by hand. It should turn freely with no grinding or wobble.
4. Reseat the fan motor connector on the outdoor board.
5. In heating mode in winter, ice on the fan blades after a defrost cycle can trigger this; let it thaw and retest.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

Outdoor fan motors are replaceable but sit next to high-voltage inverter components. Call a technician if the fan spins freely and the connector is tight but the code persists.

Common causes

• The zone E indoor coil outlet temperature (T2B) thermistor has failed (they do drift and fail with age and heat cycling).
• Its plug has worked loose from the control board, or a pin has corroded.
• The sensor lead is chafed, pinched or chewed, giving an intermittent open or short.
• The control board's sensor input has failed (rare compared with the sensor itself).

How to fix it yourself

Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.

1. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.
2. If the code comes straight back after a reset, the fault is real and not a glitch.
3. With power off, locate the zone E indoor coil outlet temperature sensor (T2B) on the refrigerant line for zone E inside the outdoor unit, near the port it serves. Follow its lead back to the board and reseat the plug firmly.
4. Inspect the lead for damage along its whole length, especially where it passes through the chassis.
5. If you have a multimeter, unplug the sensor and measure its resistance. A reading near zero ohms (short) or infinite (open) confirms a bad sensor. Most mini split thermistors read roughly 5 to 20 kΩ at room temperature, so a value in that range with a steady drift as you warm it in your hand means the sensor is fine and the board is the suspect.
6. Replacement thermistors are inexpensive and plug in. Match the part number from the parts list for your model.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

Sensor swaps are a doable DIY job on most units. Call a technician if the sensor tests good and the code persists, because that points at the control board.