Fujitsu AST12RSHCW - User Manual

Questions and Answers

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Mary EdwardsAug 3, 2025
Why is my Fujitsu Air Conditioner cooling performance poor?
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  fmcmahonAug 3, 2025
  Poor cooling performance in your Fujitsu Air Conditioner can stem from several factors. First, ensure the air filter isn't dirty. Check that the air conditioner's intake grille or outlet port is not blocked. Verify that the room temperature settings (thermostat) are correctly adjusted. Also, make sure no windows or doors are open, and close curtains to block bright sunlight. Finally, consider if there are too many people or heating apparatus in the room, or if the unit is set to SUPER QUIET operation.
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Christina KingAug 8, 2025
Why does my Fujitsu AST12RSHCW airflow is weak?
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  Wendy WallerAug 8, 2025
  Weak or absent airflow in your Fujitsu Air Conditioner can occur for several reasons. When heating operation is started, fan speed is temporarily very low to allow internal parts to warm up. During heating, if the room temperature rises above the thermostat setting, the outdoor unit will stop, and the indoor unit will operate at a very low fan speed. The unit will temporarily stop operation (between 7 and 15 minutes) as the automatic defrosting mode operates. During dry operation, the fan may operate at very low speed when the unit is monitoring the room’s temperature. Also, the fan will operate at very low speed during SUPER QUIET operation or in monitor AUTO operation.
K
Kelly WhiteAug 12, 2025
What to do if my Fujitsu Air Conditioner doesn't operate at all?
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  Teresa RichardsonAug 12, 2025
  If your Fujitsu Air Conditioner isn't operating, start by checking if the power supply plug is disconnected from the outlet. Then, check for a power failure in your area. Inspect the fuse to see if it has blown out, or if a circuit breaker has been tripped. Also, verify that the main POWER switch is not set to the OFF position and that the timer is not operating.
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Andrea ParkAug 16, 2025
Why does my Fujitsu AST12RSHCW smells?
- B
  Benjamin SmithAug 16, 2025
  If your Fujitsu Air Conditioner emits a smell, it's likely that room odors (from furniture, tobacco, etc.) have been drawn into the unit. As a result, these smells may be emitted from the indoor unit.
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madeline54Aug 21, 2025
Why is my Fujitsu AST12RSHCW Air Conditioner not operating immediately?
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  Jordan JonesAug 21, 2025
  Your Fujitsu Air Conditioner might not operate immediately if the unit was recently stopped and then restarted. The compressor will not operate for about 3 minutes to prevent fuse blowouts. Also, if the power supply plug was recently disconnected and then reconnected, the protection circuit will operate for about 3 minutes, preventing operation during that period.
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melissa75Aug 26, 2025
Why does my Fujitsu Air Conditioner makes noise?
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  christopherlaneAug 26, 2025
  The noises from your Fujitsu Air Conditioner can arise from several reasons: * During operation, and immediately after stopping the unit, the sound of water flowing in the air conditioner’s piping may be heard. * Particularly noticeable for about 2 to 3 minutes after starting operation, you may hear the sound of coolant flowing. * During heating operation, a sizzling sound may be heard occasionally, produced by the automatic defrosting operation.
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Frank SimsAug 29, 2025
Why does Fujitsu AST12RSHCW Air Conditioner emit mist or steam?
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  Olivia McclureAug 29, 2025
  Mist or steam emitted from your Fujitsu Air Conditioner can occur in two situations: during cooling or dry operation, a thin mist may be seen emitted from the indoor unit due to sudden cooling of room air. During heating operation, the outdoor unit’s fan may stop, and steam may be seen rising from the unit due to automatic defrosting operation.

Summary

Features and Functions

Automatic Operation

Starts operation automatically based on room temperature and thermostat settings.

Sleep Timer

Adjusts thermostat for sleep and auto-turns off unit at set time.

Wireless Remote Control Unit

Provides convenient control over the air conditioner's operation.

Swing Operation

Louvers swing automatically to distribute air evenly throughout the room.

Removable Intake Grille

Indoor unit's grille is removable for easy cleaning and maintenance.

Mildew-Resistant Filter

Air filter treated to resist mildew, ensuring cleaner use and easier care.

Super Quiet Operation

Reduces airflow for quieter operation by selecting the QUIET mode.

Air Cleaning Filter (Optional)

Optional filter cleans air using an electrostatic principle.

Power Diffuser (for warm air to your feet)

Directs airflow downwards to warm feet quickly and efficiently.

Safety Precautions

Warning!

Important safety alert regarding potential hazards and precautions.

Danger!

Critical safety alert for severe risks and user non-serviceable parts.

Caution!

Safety advice to prevent minor injury, damage, or improper use.

Name of Parts

Fig. 1 Indoor Unit

Identifies components and labels for the indoor unit.

Fig. 5 Outdoor Unit

Identifies components and labels for the outdoor unit.

Fig. 6 Remote Control Unit

Identifies buttons, indicators, and functions of the remote control.

Remote Control Unit Display (Fig. 8)

Explains the indicators and displays shown on the remote control screen.

Preparation

Turn on the Power

Steps to connect the power supply and turn on the air conditioner.

Load Batteries

Instructions for inserting batteries into the remote control unit.

Set the Current Time

Guide to setting the current time on the remote control for timer functions.

To Use the Remote Control Unit

Notes on operating the remote control, including range and signal reception.

Remote Control Unit Holder

Instructions for mounting the remote control holder.

Operation

To Select Mode Operation

How to start the unit and select operating modes (Auto, Heat, Cool, Dry, Fan).

To Set the Thermostat

Instructions for adjusting the desired temperature using the remote control.

To Set the Fan Speed

How to change the fan speed settings (Auto, High, Med, Low, Quiet).

To Stop Operation

Procedure to stop the air conditioner operation.

About AUTO CHANGEOVER Operation

How the unit automatically selects operating modes based on room conditions.

About Mode Operation

Details on how Heating, Cooling, Dry, and Fan modes function.

Timer Operation

To Use the ON Timer or OFF Timer

Steps to set a specific time for the unit to turn on or off.

To Use the PROGRAM Timer

Allows integration of OFF and ON timer operations in a single sequence.

To Cancel the Timer

Procedure to cancel any active timer settings.

To Stop Air Conditioner Operation while the Timer is Operating

How to manually stop the unit when a timer is active.

To Change the Timer Settings

Instructions for modifying existing timer settings.

Sleep Timer Operation

To Use the SLEEP Timer

Sets the length of time until the air conditioner operates to stop.

To Change the Timer Settings

Procedure to modify the sleep timer settings.

To Cancel the Timer

Cancels the sleep timer operation and returns to normal mode.

To Stop the Air Conditioner During Timer Operation

Allows manual stoppage of the unit while the sleep timer is active.

About the SLEEP Timer

Explains how the sleep timer automatically modifies thermostat settings.

Adjusting the Direction of Air Circulation

Vertical Air Direction Adjustment

How to adjust the vertical airflow direction using the remote control.

Right-Left Adjustment

Manual adjustment of the right-left louvers for preferred airflow direction.

Swing Operation

To Select SWING Operation

Activates automatic swinging of the Air Flow Direction Louvers.

To Stop SWING Operation

Deactivates the automatic swinging of the Air Flow Direction Louvers.

About Swing Operation

Notes on swing range, automatic switching, and temporary stops.

Manual Auto Operation

How To Use the Main Unit Controls

Instructions for operating the unit using controls on the main unit panel.

Cleaning and Care

Remove the Intake Grille

Steps to remove the indoor unit's intake grille for cleaning.

Clean with water

Instructions for cleaning the removed intake grille.

Replace the Intake Grille

Procedure for reattaching the intake grille after cleaning.

Cleaning the Air Filter

Steps for cleaning the air filter, including removal and reinstallation.

When using the optional Air Cleaning Filter

Notes on using and maintaining the optional air cleaning filter.

Troubleshooting

NORMAL FUNCTION - Doesnt operate immediately

Checks for issues when the unit does not start immediately.

NORMAL FUNCTION - Noise is heard

Identifies common sounds and their potential causes during operation.

NORMAL FUNCTION - Smells

Addresses potential smells emitted from the indoor unit.

NORMAL FUNCTION - Mist or steam are emitted

Explains the occurrence of mist or steam during cooling/dry operation.

NORMAL FUNCTION - Airflow is weak or stops

Diagnoses reasons for weak or stopped airflow, especially during heating.

NORMAL FUNCTION - Water is produced from the outdoor unit

Explains water production from the outdoor unit during heating.

CHECK ONCE MORE - Doesnt operate at all

Checks common causes for the unit failing to operate at all.

CHECK ONCE MORE - Poor Cooling performance

Troubleshoots issues related to reduced cooling efficiency.

CHECK ONCE MORE - The unit operates differently from the Remote Control Units setting

Addresses discrepancies between remote settings and unit operation.

Operating Tips

Heating Performance

Information on heat-pump efficiency and performance in low temperatures.

Microcomputer-controlled Automatic Defrosting

Details on the automatic defrosting function during heating in cold conditions.

AUTO Restart - In Event of Power Interruption

Explains how the unit restarts automatically after a power failure.

Temperature and Humidity Range

Specifies the recommended operating temperature and humidity ranges for each mode.

Fujitsu AST12RSHCW Specifications

General

Type	Split System
Cooling Capacity	3.5 kW
Heating Capacity	4.0 kW
Refrigerant	R32
Weight (Indoor Unit)	9 kg
Noise Level (Outdoor Unit)	50 dB(A)
Power Supply	220-240V, 50Hz
Coefficient of Performance (COP)	4.0
Noise Level (Indoor Unit)	42 dB(A)