Fujitsu AST18 SERIES - User Manual

Questions and Answers

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Keith StaffordAug 14, 2025
Why is my Fujitsu Air Conditioner cooling (or heating) poorly?
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  Douglas FuentesAug 14, 2025
  Poor cooling or heating performance in your Fujitsu Air Conditioner can be due to several reasons: * A dirty air filter. * Blocked intake grille or outlet port. * Incorrect room temperature settings. * Open window or door. * Bright sunlight entering the window during Cooling operation (close the curtains). * Too many people or heating apparatus and computers inside the room during Cooling operation.
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Deborah DixonAug 18, 2025
What to do if my Fujitsu AST18 doesn’t operate at all?
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  webstersierraAug 18, 2025
  If your Fujitsu Air Conditioner doesn’t operate at all, check the following: * Has there been a power failure? * Has a fuse blown out, or a circuit breaker been tripped? * Is the timer operating?
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Christine BrownAug 25, 2025
What to do if my Fujitsu AST18 Air Conditioner operates differently from the remote control unit’s setting?
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  Julia HenryAug 25, 2025
  If your Fujitsu Air Conditioner operates differently from the remote control unit’s setting, check if: * The remote control unit’s batteries are dead. * The remote control unit’s batteries are loaded properly.
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Hannah WhitakerAug 27, 2025
Why is water produced from the outdoor unit of my Fujitsu Air Conditioner?
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  kingmicheleAug 27, 2025
  During Heating operation, water may be produced from the outdoor unit of your Fujitsu Air Conditioner due to the Automatic Defrosting operation.
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elizabethwagnerAug 31, 2025
Why is there noise coming from my Fujitsu Air Conditioner?
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  Jessica JohnsonAug 31, 2025
  The noises you hear from your Fujitsu Air Conditioner could be due to: * The sound of water flowing in the air conditioner’s piping during operation and immediately after stopping the unit. * The sound of coolant flowing, which may be particularly noticeable for about 2 to 3 minutes after starting operation. * A sizzling sound during Heating operation, which is produced by the Automatic Defrosting operation.
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Steven GreeneSep 3, 2025
Why is my Fujitsu Air Conditioner emitting mist or steam?
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  Michael HarrisonSep 3, 2025
  The emission of mist or steam from your Fujitsu Air Conditioner can be caused by: * 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.
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Tiffany BraunSep 6, 2025
Why Fujitsu AST18 Air Conditioner doesn't operate immediately after turning it on?
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  Jennifer DennisSep 6, 2025
  Your Fujitsu Air Conditioner might not operate immediately because: * 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 electrical breaker is turned off then on again or the power supply plug is disconnected and then reconnected, the protection circuit will operate for about 3 minutes, preventing unit operation during that period.
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John MartinezSep 10, 2025
Why does my Fujitsu AST18 Air Conditioner smell?
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  Megan DiazSep 12, 2025
  A smell emitted from your Fujitsu Air Conditioner's indoor unit may be the result of room smells (furniture, tobacco, etc.) which have been taken into the air conditioner.
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Erin JordanNov 20, 2025
Why does the Fujitsu AST18 airflow become weak or stop?
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  Julie RomeroNov 20, 2025
  Weak or stopped airflow in your Fujitsu Air Conditioner can occur due to several reasons: * When 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. * During Heating operation, the unit will temporarily stop operation (between 7 and 15 minutes) as the Automatic Defrosting mode operates. * The fan may operate at very low speed during Dry operation or when the unit is monitoring the room’s temperature. * In the monitor AUTO operation, the fan will operate at very low speed. * In case of Multi-type unit, if multiple units are operated in different operation modes...