Home » Fujitsu Air Conditioning troubleshooting

Fujitsu Air Conditioning troubleshooting

In the event of a malfunction (burning smell, etc.), immediately stop operation, turn off the electrical breaker or disconnect the power supply plug, and consult authorized service personnel.

Merely turning off the unit’s power switch will not completely disconnect the unit from the power source. Always be sure to turn off the electrical breaker or disconnect the power supply plug to ensure that power is completely off.

Fujitsu air conditioning doesn’t operate immediately

  • If the unit is stopped and then immediately started again, the compressor will not operate for about 3 minutes, in order to prevent fuse blowouts.
  • Whenever the Power Supply Plug is disconnected and then reconnected to a power outlet, the protection circuit will operate for about 3 minutes, preventing unit operation during that period.

Noise is heard

  • During operation and immediately after stopping the unit, the sound of water flowing in the air conditioner’s piping may be heard. Also, noise may be particularly noticeable for about 2 to 3 minutes after starting operation (sound of coolant flowing).
  • During operation, a slight squeaking sound may be heard. This is the result of minute expansion and contraction of the front cover due to temperature changes.


Some smells may be emitted from the indoor unit. This smell is the result of room smells (furniture, tobacco, etc.) which have been taken into the air conditioner.

Mist or steam are emitted

  • During Cooling or Dry operation, a thin mist may be seen emitted from the indoor unit. This results from the sudden Cooling of room air by the air emitted from the air conditioner, resulting in condensation and misting.
  • During Heating operation, the outdoor unit’s fan may stop, and steam may be seen rising from the unit. This is due to the Automatic Defrosting operation.

Airflow is weak or stops

  • When the Heating operation is started, fan speed is temporarily very low, to allow internal parts to warm up.
  • During Heating operation, if the room temperature rises above the thermostat setting, the outdoor unit will stop, and the indoor unit will operate at very low fan speed. If you wish to warm the room further,
  • set the thermostat for a higher setting.
  • During Heating operation, the unit will temporarily stop operation (between 7 and 15 minutes) as the Automatic Defrosting mode operates.
  • During the Automatic Defrosting operation, the OPERATION Indicator Lamp will flash.
  • The fan may operate at a very low speed during Dry operation or when the unit is monitoring the room’s temperature.
  • During SUPER QUIET operation, the fan will operate at a very low speed.
  • In the monitor AUTO operation, the fan will operate at a very low speed.

Water is produced from the outdoor unit

During Heating operation, water may be produced from the outdoor unit due to Automatic Defrosting operation.

Doesn’t operate at all

  • Is the Power Supply Plug disconnected its outlet? Has there been a power failure?
  • Has a fuse blown out, or a circuit breaker been tripped?

Poor Cooling performance

  • Is the Air Filter dirty?
  • Air the air conditioner’s intake grille or outlet port blocked?
  • Did you adjust the room temperature settings (thermostat) correctly?
  • Is there a window or door open?
  • In the case of the Cooling operation, is a window allowing bright sunlight to enter? (Close the curtains.)
  • In the case of Cooling operation, are there heating apparatus and computers inside the room, or are there too many people in the room?