Mitsubishi Heavy Industries Air Conditioner User Manual

General Precautions

⚠️ WARNING: Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.

❗ CAUTION: Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury or property damage.

Please adhere to these precautions for your safety.

• This unit is designed for refrigerants R32 or R410A. Check the outdoor unit label for refrigerant information.
• Symbols used in this manual: ? (Strictly prohibited), ✔️ (Handle with care), ⚡ (Ensure proper grounding).
• Refer to the user and installation manuals for detailed information.
• Service personnel should refer to the installation manual.
• For R32 units: This equipment uses flammable refrigerant. If a leak occurs in the presence of an ignition source, there is a risk of ignition.

General Warnings:

• National laws regarding disposal must be strictly followed.
• Do not use any means other than those recommended by the manufacturer to accelerate defrosting or cleaning.
• Store the unit in a well-ventilated area appropriate for its operation.
• Do not use the unit where ignition sources are present (e.g., open flames, gas appliances).
• Do not pierce or incinerate the unit.
• Be aware that refrigerants may have odors.

Installation Precautions

⚠️ WARNING:

• This system is intended for domestic and residential use. Use in harsh environments (e.g., workshops) may lead to poor performance.
• Installation must be performed by your seller or a qualified installer. Improper installation can cause water leaks, electric shock, or fire.

❗ CAUTION:

• Do not install where flammable gases may leak, as this can cause fires.
• Ensure an earth leakage circuit breaker is installed. Failure to do so may result in electric shock.
• Ensure the drain pipe is installed correctly for complete drainage. Improper installation can cause water dripping, potentially damaging furniture.
• Ensure the system is properly grounded. Never connect the ground wire to gas pipes, water pipes, lightning conductors, or telephone ground wires. Incorrect grounding can cause electric shock.

Environmental Information: This product contains fluorinated greenhouse gases. R32 has a Global Warming Potential (GWP) of 675. R410A has a GWP of 2088. Consult the outdoor unit's nameplate for the amount of refrigerant and its CO2 equivalent.

Operation Precautions

⚠️ WARNING:

• Children should not play with the air conditioner.
• Avoid prolonged exposure to cold airflow, as it may affect your physical condition and health.
• Children should not perform cleaning or maintenance without supervision.
• Do not insert anything into the air outlets, as this could damage the fan or cause other issues.
• This air conditioner can be used by children aged 8 and above, and persons with reduced physical, sensory, or mental capabilities, if supervised or instructed on safe use and the associated hazards.
• Keep the remote control out of reach of children to prevent accidental ingestion of batteries or other accidents.

❗ CAUTION:

• Use only approved fuses. Do not use steel or copper wire as a substitute for a fuse, as this can cause damage or fire.
• Do not handle switches with wet hands to avoid electric shock.
• Do not hang or swing from the indoor unit; a fall could cause injury.
• Keep flammable insecticides or aerosol sprays away from the air conditioner.
• Do not expose combustion appliances directly to the airflow, as it may affect their performance.
• Do not wash the air conditioner with water, as this can cause electric shock. High-pressure cleaning systems may damage the aluminum fins, reducing efficiency.
• Do not place items containing water (e.g., vases) on the unit. Water ingress can damage insulation and cause electric shock.
• Do not install the unit where airflow is directed at animals or plants, as it may affect their health.
• Do not step on, sit on, or place objects on the unit. A fall could cause injury.
• Periodically check the unit's support structure. If damage is not repaired promptly, the unit could fall and cause injury.
• Do not touch the aluminum fins of the heat exchanger, as this can cause personal injury.
• Do not place any electrical appliances or objects under the indoor or outdoor units. Condensation may stain items and cause accidents or electric shock.
• Do not operate the system without the air filter. This can lead to system malfunction due to heat exchanger obstruction and drain pump blockage.
• Ventilate the room regularly when using the air conditioner with combustion appliances. Insufficient ventilation can lead to oxygen deficiency.
• When cleaning, stop the unit and disconnect the power. Never open the panel while the fan is rotating.
• Do not place objects near the outdoor unit or allow leaves to accumulate around it, as small animals may enter and contact electrical components, causing malfunctions, smoke, or fire.
• Do not disconnect the power immediately after stopping the unit. Wait at least 5 minutes to avoid water leakage or unit damage.
• Do not control the system using the main power switch, as it may cause fire, water leakage, or unexpected fan operation.
• Avoid spilling liquids or placing water containers on the unit. Water ingress can damage insulation and cause electric shock.
• Contact your distributor for internal unit cleaning. Do not attempt it yourself, as incorrect detergents or methods can damage plastic parts and cause leaks. Detergent contact with electrical components can cause damage, smoke, or fire.
• If you hear thunder or suspect lightning, stop the unit and disconnect the power to prevent damage.
• If the power cord is damaged, contact your distributor or a qualified installer for replacement to avoid hazards.

Relocation and Repair Precautions

⚠️ WARNING:

• Do not perform any repairs or modifications. Consult the unit's supplier. Unauthorized repairs can cause water leaks, electric shock, or fire.
• For repairs, consult your distributor. Incorrect repairs can cause electric shock, fire, etc.
• If relocating the air conditioner, contact your distributor or a qualified installer. Improper installation can lead to water loss, electric shock, or fire.
• If you detect any abnormality (e.g., burnt smell), stop the system, disconnect power, and consult your distributor. Continued operation under abnormal conditions can lead to malfunction, electric shock, or fire.
• If the air conditioner is not cooling or heating properly, it may be due to a refrigerant leak. Contact your distributor. If refrigerant needs to be added, contact your supplier for instructions. Refrigerant contact with skin can cause cold injury. Inhaling refrigerant gas excessively may temporarily impair nervous system function (dizziness, headache) or cardiac function (arrhythmia, palpitations). If refrigerant leaks onto a heater, stove, or iron, harmful gases may be generated.

Indoor Unit

Air Inlet: Where air is drawn in.

Air Outlet: Where air is blown out.

Air Filter: Removes dust and dirt from the air inlet. (See page 26 for cleaning instructions).

Refrigerant Pipe and Electrical Cable Connection: Connects the indoor and outdoor units.

Unit Display Section (Remote Signal Receiver): Receives signals from the remote control.

Drain Hose: Drains water from the indoor unit.

Accessories

• Remote Control: Wireless remote control unit.
• Remote Control Holder: For mounting the remote control on a wall.
• Wood Screws (x2): For mounting the remote control holder.
• Batteries (x2): R03 (AAA, Micro).

Outdoor Unit

Air Inlet: Located on the side and rear surfaces.

Air Outlet: Where air is expelled.

Outdoor Unit Fan: Circulates air.

Heat Exchanger: Transfers heat.

Remote Control Display and Indicators

The remote control display shows operating status, temperature, and timer settings. Key indicators include:

• RUN Light (Green): Illuminates during operation. Blinks during HOT KEEP or SELF CLEAN mode pauses.
• TIMER Light (Yellow): Illuminates during timer operation.
• HI POWER Light (Green): Illuminates during HIGH POWER operation. Blinks during heating preparation.
• ECONO Light (Orange): Illuminates during ECONOMY operation.

Acoustic Signals: The unit emits 'PIPI' sounds for certain settings (e.g., 24°C auto mode) and 'PI' for ON/OFF operations (except SELF CLEAN).

Remote Control Buttons

The remote control features various buttons for operation:

• MODE: Selects operating mode (AUTO, COOL, HEAT, DRY, FAN).
• TEMP (▲/▼): Adjusts the temperature.
• HI/ECO: Switches between HIGH POWER and ECONOMY modes.
• SILENT: Activates SILENT mode for quieter operation.
• ON TIMER: Sets the auto-on timer.
• OFF TIMER: Sets the auto-off timer.
• WEEKLY: Activates/deactivates the weekly timer.
• SLEEP: Activates the SLEEP timer (auto-off with temperature adjustment).
• MENU: Selects SELF CLEAN or PRESET modes.
• FAN SPEED: Adjusts fan speed (AUTO, ULo, Lo, Me, Hi).
• AIR FLOW (U/D): Adjusts airflow direction (up/down).
• NIGHT SETBACK: Activates comfort mode for nighttime.
• SET / Child Lock: Confirms settings or activates/deactivates child lock.
• CANCEL: Cancels timer operations.
• TIMER: Sets the current time and timer functions.
• PROGRAM: Sets the weekly timer.
• ACL: Resets the microcomputer.
• TIME SET UP: Used for setting the current time.

Installation Examples

The manual illustrates two types of ceiling-concealed installations: one with side air outlet and one with downward air outlet. Both show the indoor unit integrated into the ceiling, with air inlets and outlets clearly marked, along with the location of the remote signal receiver.

Battery Replacement

Replace batteries when the unit does not respond to the remote or the display fades. Follow these steps:

1. Remove the cover and take out the old batteries.
2. Insert two new R03 (AAA) batteries, observing polarity.
3. Close the cover.
4. Press the ACL button with a pen tip.

Notes: Do not mix old and new batteries. Remove batteries if the remote will not be used for an extended period. Battery life is typically 6-12 months.

Remote Control Holder

The remote control can be mounted on a wall using the provided holder for convenient access.

Remote Control Handling Warnings

• Avoid placing the remote in high temperatures or near heating appliances.
• Do not place obstructions between the remote and the unit's display section.
• Keep the remote away from direct sunlight and intense lighting.
• Do not spill any liquid on the remote control.
• Handle the remote with care to avoid dropping it.
• Do not place heavy objects on the remote or stand on it.

Remote Control Failure

If the remote control fails:

• Check if the batteries are depleted and replace them.
• Use the unit's temporary ON/OFF button for operation.
• Contact your distributor for remote control inspection or replacement.

Temporary Operation

The ON/OFF button on the unit itself allows temporary operation when the remote control is unavailable. The unit will operate in AUTO mode with AUTO fan speed. Press the button once to turn on, and again to turn off. Note: Holding the button for more than 5 seconds may initiate maintenance mode.

Child Lock

This function locks the remote control to prevent accidental operation. To activate, press and hold the SET button for 3 seconds or more. The display will show '3'. While active, only the ON/OFF button works. To deactivate, press and hold SET again for 3 seconds.

AUTO Mode

The air conditioner automatically selects the operating mode (COOL, HEAT) based on the room temperature when started. If operating multiple indoor units, AUTO mode may lead to the outdoor unit stopping if room temperatures vary significantly. In such cases, using COOL or HEAT mode directly is recommended.

Operation: Press MODE to cycle through modes, then press ON/OFF to start. Press ON/OFF again to stop.

Note: If no air is outputted during heating, refer to page 28.

AUTO Mode Temperature Adjustment

In AUTO mode, the default temperature is 24°C. You can adjust this between 18°C and 30°C using the ▲ or ▼ (TIMER) buttons.

FAN SPEED

Select fan speed (AUTO, ULo, Lo, Me, Hi) using the FAN SPEED button. This function is not available in DRY mode. Changing from high to low speeds may produce a refrigerant flow sound.

Airflow Direction

The airflow direction can be adjusted up or down using the AIR FLOW button. While the remote display will change, the unit's louvers may not move accordingly.

COOL/HEAT/DRY/FAN Modes

Select the desired mode (COOL, HEAT, DRY, FAN) using the MODE button. Recommended settings are:

• COOL: 26°C-28°C
• HEAT: 22°C-24°C
• DRY: 24°C-26°C

Adjust temperature and fan speed as needed. The unit can be operated or mode changed while it is running.

Operating Temperature and Humidity Limits

Ensure operation within these limits to prevent protection device activation:

• Outdoor Temperature: -15°C to 46°C (Cooling), -15°C to 24°C (Heating)
• Indoor Temperature: 18°C to 32°C (Cooling), 10°C to 30°C (Heating)
• Indoor Humidity: Below 80%. High humidity may cause condensation and water leakage.

HEAT Mode Characteristics

Mechanism: The unit heats outdoor air and transfers it indoors. Heating capacity decreases in low outdoor temperatures. A delay may occur before warm air is supplied. Additional heating may be needed in very low temperatures.

Defrosting: In cold, humid conditions, the outdoor heat exchanger may freeze, reducing heating efficiency. The unit automatically enters a defrost cycle (5-15 minutes), during which the RUN light blinks, and the fan may stop. Water vapor may be emitted from the outdoor unit during defrosting. The unit resumes heating after defrosting.

SLEEP TIMER (Auto-off)

The unit automatically turns off after a set time. The temperature adjusts automatically to prevent excessive cooling or heating. Set the timer using the SLEEP button. The yellow timer light indicates it is active. To cancel, press SLEEP or MODE.

OFF TIMER (Auto-off)

The unit turns off at a preset time. Set the timer using the OFF TIMER button, then adjust the time using the ▲ or ▼ (TIMER) buttons and confirm with SET. The yellow timer light indicates it is active. To cancel, press CANCEL.

ON TIMER (Auto-on)

The unit turns on 5-60 minutes before the set time to reach optimal room temperature. Set the timer using the ON TIMER button, adjust time with ▲ or ▼ (TIMER) buttons, and confirm with SET. The yellow timer light indicates it is active. To cancel, press CANCEL. Note: Pressing ON/OFF after setting ON TIMER cancels the setting.

SLEEP TIMER + ON TIMER Combined Operation

You can combine SLEEP TIMER (auto-off) and ON TIMER (auto-on) functions. For example, set the unit to turn off after 3 hours and then turn on again by 8:00 AM.

ON TIMER + OFF TIMER Combined Operation

Combine ON TIMER and OFF TIMER settings for sequential operation. The unit can be set to turn off at a specific time and then turn on later. The 'Comfort Start' feature ensures the room reaches the desired temperature by the ON TIMER's set time.

Weekly Timer

Set up to 4 programs per day for a total of 28 programs. The timer repeats weekly unless cancelled. Activate/deactivate the weekly timer using the WEEKLY button. The yellow timer light illuminates when active. Notes on timer interaction and program limits apply.

HIGH POWER / ECONOMY Modes

HIGH POWER: Intensifies cooling/heating for 15 minutes for rapid temperature change. It cancels if HIGH POWER is pressed again, the mode is changed, 15 minutes pass, or SILENT/NIGHT SETBACK is activated.

ECONOMY: Provides smoother, energy-saving operation. The unit adjusts temperature by +1.5°C (cooling) or -2.5°C (heating) relative to the set point. The 'eco' symbol appears. It cancels if HI/ECO is pressed again, the mode is changed, or NIGHT SETBACK is activated.

NIGHT SETBACK Mode

Maintains room temperature around 10°C for comfort during cooler periods or when the room is unoccupied. Temperature cannot be adjusted in this mode. It is not compatible with HIGH POWER or ECONOMY modes.

Cancellation: Press NIGHT SETBACK or MODE.

SILENT Mode

Reduces the noise level of the outdoor unit for quieter operation. It is not available in DRY or FAN modes. It will resume if the unit is turned off and on again, or if SLEEP/OFF TIMER/SELF CLEAN is cancelled. Note: Noise reduction may vary by model.

MENU Function

Use the MENU button to select SELF CLEAN or PRESET operating modes.

SELF CLEAN Operation

This function runs for approximately 2 hours after AUTO, COOL, or DRY operation to remove internal moisture and prevent mold growth. The RUN light will be illuminated. To stop immediately, press ON/OFF. To cancel and switch to SLEEP or NIGHT SETBACK, press those buttons. This function does not remove existing mold or dirt.

PRESET Function

Allows you to save your preferred settings (mode, temperature, fan speed, airflow direction) for quick recall. After selecting preferences, press SET. Then, press MODE for over 3 seconds to activate PRESET mode.

Auto Restart Function

The unit automatically resumes its previous operating state after a power interruption. Timer settings and HIGH POWER operations are cancelled.

Tips for Effective Operation

• Set a comfortable room temperature to save energy and promote well-being.
• Adjust airflow direction for even temperature distribution.
• Clean air filters regularly for optimal performance and energy efficiency. Professional cleaning is recommended.
• Operate the unit only when necessary, utilizing timer functions.
• Avoid direct sunlight and drafts. Keep windows and doors closed during cooling.
• Keep heat sources away from the unit when cooling.

Before Maintenance

• Always disconnect the power supply before performing any maintenance.
• Do not spill liquids on the unit.
• Clean the unit with a soft, dry cloth.
• Do not touch the aluminum fins of the heat exchanger.
• Do not use hot water (over 40°C), gasoline, solvents, or abrasive cleaners, as they can deform or scratch the unit.

During Operation

Air Filter Cleaning: Clean the air filter regularly. Professional cleaning is recommended. Note: The air filter cannot be washed with water. A clogged filter reduces cooling/heating capacity, increases noise, and wastes energy.

End of Season Maintenance

1. Run the fan for 2-3 hours to dry the interior.
2. Turn off the unit and disconnect the power supply (the unit consumes approx. 2W even when off).
3. Clean and reinstall the air filters.
4. Remove batteries from the remote control.

Beginning of Season Maintenance

1. Ensure the grounding wire is not pinched or disconnected.
2. Check the outdoor unit frame for corrosion or rust.
3. Ensure no obstacles block airflow around the indoor and outdoor unit vents.
4. Connect the power supply.
5. Insert batteries into the remote control.

Correct Installation Position

Ensure proper ventilation by not placing objects in front of the indoor unit. Avoid installation in locations prone to flammable gas leaks, oil splashes, corrosive atmospheres (sea breeze, sulfurous gases), or near electronic devices (TV, radio) that may cause interference. Ensure the drain hose discharges water correctly. Install the unit on a stable, vibration-free surface. Avoid locations where noise or airflow may disturb neighbors. Keep air inlet/outlet areas clear.

Troubleshooting Guide

Before contacting a distributor, check the following:

• Unit not operating: Check if the power switch is on, if the timer is set, or if there is a power failure or blown fuse.
• Poor cooling/heating: Check if the room temperature is set correctly. Ensure air filters are clean and not obstructed. Check for open windows or doors. Ensure direct sunlight is not entering the room. Check for heat sources in the room or excessive occupancy.

If problems persist after these checks, or if specific error conditions (refer to page 28 or 29 of the manual) are met, interrupt power and contact your distributor.

Airflow Notices

• No airflow during heating start-up: The unit waits 2-5 minutes for the heat exchanger to warm up (HOT KEEP function). The RUN light blinks (1.5s ON, 0.5s OFF).
• Delayed heating or weak warm air: This can occur in low outdoor temperatures with high humidity, triggering an automatic defrost cycle. The RUN light blinks. Wait for defrosting to complete.
• No airflow during DRY mode start-up: The RUN light illuminates.

Noise Notices

• Water running sound: This is the normal sound of refrigerant circulating within the unit.
• Cracking sound: Caused by expansion/contraction of plastic parts.
• Hissing sound: Caused by refrigerant control valves or electrical components.
• Whistling sound: Indicates the compressor speed is increasing or decreasing.
• 'Shoooo' sound upon shutdown: Produced when stopping operation of another indoor unit.

Other Notices

• Unit not restarting immediately: A 3-minute protection timer prevents immediate restart after shutdown. The RUN light may stay on.
• No air during heating start-up: See Airflow Notices.
• No air during DRY mode start-up: See Airflow Notices.
• Mist in COOL operation: Normal condensation.
• Unpleasant odor: May be caused by tobacco, cosmetics, or other substances absorbed by the unit.
• Unit does not restart after power outage: Ensure the auto-restart function is enabled. If not, restart manually using the remote.
• Remote signals not received: Ensure the unit's display is not exposed to direct sunlight or bright lights.
• Moisture formation at air outlets: Can occur after prolonged operation in high humidity.
• Fan not stopping immediately: The indoor fan may run for up to 2 hours in SELF CLEAN mode. The outdoor fan runs for about 1 minute for protection. The RUN light may stay on during SELF CLEAN.

Contact Your Distributor

Contact your distributor immediately if you experience any of the following:

• Frequent blown fuses or switches.
• Overheating power cord or damaged cord cover.
• Damage to the power cord (requires qualified repair).
• Interference with TVs, radios, or other electronics.
• Unreliable switch operation or abnormal noises.
• Foreign objects entering the unit or airflow regulator malfunction.
• Unit not functioning with blinking RUN and TIMER lights (0.5s ON, 0.5s OFF).

If irregularities persist after a power cycle, contact your distributor.

Multi-unit Air Conditioner Operation

• Simultaneous Operation: Indoor units cannot operate in different modes (e.g., COOL and HEAT) simultaneously. The first unit started has priority. To change priority, either stop the prioritized unit or match its mode to the other unit. The RUN light illuminates if units operate in different modes.
• Automatic Operation: In AUTO mode, the system selects cooling, drying, or heating based on room temperature. In multi-unit systems, AUTO mode may cause the outdoor unit to stop if room temperatures vary; use COOL or HEAT mode directly in such cases.
• Refrigerant Oil Recovery: If indoor units have been inactive for a long period, performance may temporarily decrease. A process to recover refrigerant oil may occur, potentially producing sounds of refrigerant flow.

Self-Diagnosis Function

The unit has a self-diagnosis feature to help identify problems. Error codes are indicated by the blinking patterns of the RUN and TIMER lights:

• RUN Light Blinking:
  • 1 blink: Heat exchanger sensor 1 error.
  • 2 blinks: Room temperature sensor error.
  • 3 blinks: Heat exchanger sensor 3 error.
  • 4 blinks: Drainage error.
  • 5 blinks: Active filter voltage error.
  • 6 blinks: Indoor fan motor error.
  • 7 blinks: Insufficient refrigerant or closed service valve.
• TIMER Light Blinking:
  • 1 blink: Outdoor temperature sensor error.
  • 2 blinks: Outdoor heat exchanger liquid pipe sensor error.
  • 4 blinks: Evacuation pipe sensor error.
  • 5 blinks: Suction pipe sensor error.
• Continuous RUN Light Blinking:
  • 1 blink: Power failure.
  • 2 blinks: Outdoor unit error.
  • 3 blinks: Overcurrent (compressor lock, open phase, power transistor short, closed service valve).
  • 4 blinks: Power transistor error.
  • 5 blinks: Compressor overheating.
  • 6 blinks: Signal transmission error.
  • 7 blinks: Outdoor fan motor error.
  • Continuous blinking: Refrigeration overpressure protection.
• RUN Light Blinking Twice:
  • 1 blink: Rotor lock.
  • 2 blinks: Closed service valve.

Refer to the manual for detailed causes and solutions for each error code.

EU Declaration of Conformity

Mitsubishi Heavy Industries Thermal Systems, Ltd. declares that the Split Type Air Conditioner (various models listed) conforms with EU Directives: Machinery 2006/42/EC, and applied standards EN 60335-1, EN 60335-2-40. The authorized representative in the EU is MHIAE SERVICES B.V.

UK Declaration of Conformity

Mitsubishi Heavy Industries Thermal Systems, Ltd. declares that the Split Type Air Conditioner (various models listed) conforms with UK Directives: Supply of Machinery Regulations S.I. 2008/1597, and applied standards EN 60335-1, EN 60335-2-40. The authorized representative in the GB is Mitsubishi Heavy Industries Air-Conditioning Europe, Ltd.