Mitsubishi Electric Split-type Air-Conditioner

Introduction

This document provides installation instructions for Mitsubishi Electric Split-type Air-Conditioners. It is intended for installers and covers essential information for the safe and correct installation of the outdoor unit.

Important Safety Precautions

WARNING: This unit uses a flammable refrigerant (R32). Improper installation or handling can lead to fire, electric shock, injury, or refrigerant leakage, which may produce toxic gas when exposed to heat or flame.

• Do not attempt to install the unit yourself. Contact a qualified dealer or authorized service personnel.
• Follow all instructions in this manual precisely.
• Use appropriate safety gear and tools during installation.
• Ensure the installation location can support the unit's weight.
• Electrical work must be performed by a qualified electrician. Ensure the unit is connected to a dedicated, properly fused circuit.
• Do not damage power cables.
• Disconnect power before working on electrical panels.
• Use specified connection pipes and wires. Do not use extension cords or intermediate connections.
• Never install where flammable gases may leak.
• Do not connect the power cord via extension cords or use multi-outlet power strips.
• Use only supplied or specified parts.
• Ensure electrical connections are clean and secure.
• Properly attach all covers, including the maintenance panel on the outdoor unit.
• Ensure no substance other than the specified refrigerant (R32) enters the refrigerant circuit.
• Ventilate the area if refrigerant leaks occur.
• Use appropriate tools and piping materials rated for the refrigerant pressure.
• When pumping down refrigerant, shut off the compressor before disconnecting refrigerant lines.
• Securely connect refrigerant lines before starting the compressor.
• Tighten flare nuts with a torque wrench as specified.
• Ensure electrical connections comply with national regulations and that the unit is properly grounded.
• Install a ground fault interrupter (GFI).
• Ensure the area is well-ventilated and free of ignition sources if using a gas burner or flame-producing device.
• Do not use unauthorized methods for defrosting or cleaning.
• Do not puncture or incinerate the unit.
• Be aware that refrigerants can be odorless.
• Protect piping from physical damage and minimize piping length.
• Ensure compliance with national gas regulations.
• Keep all ventilation openings clear.
• Do not use low-temperature brazing alloys for refrigerant lines.
• Perform maintenance only as recommended by the manufacturer.
• Do not modify the unit.

CAUTION:

• Install a ground fault interrupter (GFI) depending on the installation location to prevent electric shock.
• Follow instructions carefully for drain/piping work to prevent water leakage and damage to household items.
• Do not touch the air inlet or aluminum fins of the outdoor unit, as this can cause injury.
• Avoid installing where small animals might enter, as they can cause malfunctions or fires. Keep the area around the unit clean.
• Do not operate the air conditioner during interior finishing work or floor waxing. Ensure the room is well-ventilated after such work before operating the unit to prevent water leaks or condensation.

Technical Data

Note: Power consumption may vary depending on the combination of indoor units.

Installation Site Selection

Choose a location that:

• Is not exposed to strong winds.
• Ensures good airflow and is free from dust.
• Avoids rain and direct sunlight as much as possible.
• Does not disturb neighbors with operating noise or hot air.
• Has a solid wall or support to prevent amplification of noise and vibrations.
• Is not in an area where flammable gases may leak.
• Is level for installation.
• Is at least 3 meters away from TV or radio antennas to avoid reception interference.
• Is protected from snowfall or blowing snow. Consider awnings or bases in heavy snow areas.

Avoid the following locations to prevent interference or damage:

• Areas where flammable gases may leak.
• Areas with heavy machine oil.
• Areas with oil splashes or oil mist (e.g., kitchens, factories).
• Areas with salty air (near the sea).
• Areas with sulfurous gases (e.g., hot springs).
• Areas with high-frequency or wireless equipment.
• Areas with high concentrations of volatile organic compounds (VOCs) like phthalates or formaldehyde.

Required Clearances for Outdoor Unit

Ensure adequate space around the outdoor unit for proper airflow and maintenance. Specific clearances are required depending on the presence of obstacles above, in front, behind, or on the sides of the unit. Refer to diagrams for precise measurements (in mm):

• Obstacles Above: If no obstacles are in front or on the sides, an obstacle above is permissible if specified clearances are maintained (e.g., 100mm above, 500mm in front/sides).
• Front Opening (Air Outlet): If clearances are maintained, obstacles behind and on the sides are permissible (e.g., 100mm front, 200mm sides, 350mm rear if no top obstacle).
• Obstacles Only in Front: Requires clearance above, behind, and on both sides.
• Obstacles Front and Rear: May require an optional air outlet guide (MAC-856SG) and openings on sides and top.
• Obstacles Front, Rear, and Sides: If the unit is enclosed (e.g., porch), ensure adequate spacing to prevent reduced performance and increased power consumption. Consider an exhaust duct if airflow is insufficient. Do not install units directly behind each other.
• Maintenance Opening: Ensure a dedicated opening for service access.

Important Note on R32 Refrigerant: R32 is heavier than air and can accumulate near the floor. Ensure adequate ventilation to prevent flammable concentrations. If a leak is detected in a poorly ventilated area, do not use open flames until ventilation is secured.

Minimum Installation Space Requirements

Specific minimum installation areas (Amin in m²) are required based on the refrigerant charge (M in kg) for the unit, especially in enclosed spaces. These requirements ensure safety and performance. Refer to tables for specific values based on refrigerant quantity and installation configuration (e.g., A, B, C conditions for enclosed spaces).

Minimum installation spaces for indoor units also apply, depending on the mounting type (wall, ceiling cassette, etc.) and refrigerant charge.

Installation Drawing and Accessories

The installation drawing illustrates the placement and required clearances for the outdoor unit. Ensure all accessories are present before installation, including drain fittings, connection cables, piping, insulation, and mounting hardware.

WARNING: To prevent fire hazards, sheathe or protect refrigerant piping. External damage to piping can cause fires.

Note: Route power and connection cables at least 1 meter away from antenna cables.

Drain Piping for Outdoor Unit

Ensure proper drain piping is installed, especially in cold climates where freezing can occur. Condensate forms during heating; ensure the drain does not cause moisture damage or freezing.

Connecting Cables for Outdoor Unit

Follow these steps for connecting the indoor/outdoor unit connection cable and the power cable:

1. Remove the maintenance panel.
2. Connect the indoor/outdoor unit connection cable to the terminal block, ensuring wires are securely fastened and not exposed.
3. Tighten terminal screws and gently pull wires to confirm they are secure.
4. Repeat for all indoor units.
5. Connect the power cable.
6. Secure both cables with cable clamps.
7. Close the maintenance panel securely.

Important: Ensure each wire is connected to its correct terminal. Make the grounding wire slightly longer than others. Leave connection cables slightly longer for future maintenance.

Brazing and Pipe Connections

Precautions for R32 Refrigerant:

• Apply a small amount of refrigerant oil to flare connections.
• Use clean, seamless copper or copper alloy pipes.
• Use non-oxidizing brazing alloys only.
• Never mix refrigerants or allow air into the system.
• Use pipes of specified thickness; thinner pipes are insufficient.
• Ensure adequate ventilation and fire prevention measures.

Flaring and Connecting Pipes:

• Cut copper pipes cleanly and remove burrs carefully, keeping the pipe pointed downwards.
• Apply flare nuts before flaring.
• Perform flaring using the specified tool, ensuring dimensions match the table.
• Check the flare for smoothness and uniformity. Re-flare if necessary.
• Apply a thin layer of refrigerant oil to flare ends and connection ports.
• Tighten flare nuts by hand initially, then use a torque wrench to the specified torque. Overtightening can damage the flare nut and cause leaks.
• Insulate all exposed pipes to prevent burns or frostbite.

Pipe Connection Sizes: Refer to tables for correct pipe sizes (liquid and gas) based on indoor unit capacity and series.

WARNING: Securely connect refrigerant lines before starting the compressor.

CAUTION: Ensure unused ports have their nuts securely tightened.

Flushing Procedures and Leak Test

Leak Test and Flushing:

1. Remove the service port cap from the shut-off valve on the gas pipe side of the outdoor unit.
2. Connect a vacuum gauge and vacuum pump to the service port.
3. Run the vacuum pump for at least 15 minutes.
4. Close the gauge manifold valve, then turn off the vacuum pump.
5. Allow the system to remain under vacuum for 1-2 minutes to check for pressure drops. The gauge should indicate -0.101 MPa (-760 mmHg).
6. Quickly remove the gauge manifold from the service port.
7. Open all shut-off valves (gas and liquid) fully. Partial opening reduces performance.
8. Add the specified amount of refrigerant slowly.
9. Tighten the service port cap to restore the original state.

WARNING: Ensure no ignition sources are present before opening shut-off valves.

Refrigerant Filling:

• Connect the gas cylinder to the service port.
• Purge air from the hose.
• Fill with the specified refrigerant amount while the unit is in cooling mode.

CAUTION: Use liquid refrigerant for topping up to prevent compressor seizure. Warm the gas cylinder in warm water (below 40°C) if necessary, but never use open flames.

Record the filled refrigerant quantities and calculate CO2 equivalent as per regulations.

Maintenance Panel and DIP Switch Settings

The maintenance panel on the outdoor unit provides access to DIP switches for various settings. Follow instructions to remove and reattach the panel correctly.

Operation Mode Lock

This feature allows locking the unit into COOL/DRY or HEAT mode. Set SW1-3 ON to enable. Set SW1-4 OFF for COOL/DRY lock, or ON for HEAT lock.

Low Energy Standby Mode

Recommended when no indoor units are connected. Set via DIP switch (SW1) and jumper connector (SC751) on the outdoor unit's control board. Factory setting is disabled. Connect SC751 to CN750 to enable (SW1-2 ON), or to CN751 to disable (SW1-2 OFF).

Reducing Outdoor Unit Operating Noise

This function reduces operating noise, typically at night, by lowering the operating load. This may also reduce cooling/heating capacity. Enable by setting SW1-5 ON.

Test Run

Perform test runs for each indoor unit individually. This helps identify any issues with refrigerant piping or connection cables. Do not run all units simultaneously for the initial test.

Start-up Repetition Prevention: The compressor has a 3-minute delay after shutdown to protect it.

Wiring/Piping Correction Function: The unit has a function to detect and correct incorrect wiring/piping combinations. Follow the procedure involving SW871 (correction button) after power-on. The process takes 10-15 minutes. LEDs indicate the result. Ensure the unit is powered and shut-off valves are open. Do not touch the circuit board during this process.

User Explanation

Explain the operation of the air conditioner to the user using the User's Manual, covering remote control usage, filter cleaning, and safety precautions. Encourage the user to read the manual thoroughly.

Pumping Down

When decommissioning or moving the unit, pump down the refrigerant to prevent release into the atmosphere:

1. Turn off the breaker.
2. Connect the vacuum gauge to the outdoor unit's service port.
3. Fully close the shut-off valve on the liquid pipe side.
4. Turn on the breaker.
5. Start emergency cooling (COOL mode) on all indoor units.
6. When the vacuum gauge shows 0.05 to 0 MPa, fully close the shut-off valve on the gas pipe side and stop operation.
7. Turn off the breaker and remove the gauge and refrigerant lines.

WARNING: Shut off the compressor before disconnecting refrigerant lines to prevent explosions or injuries.

EC Declaration of Conformity

Mitsubishi Electric Consumer Products (Thailand) Co., Ltd. declares that the air conditioners and heat pumps comply with relevant EU directives, including Low Voltage, Machinery, EMC, Energy-related Products, RoHS, and Pressure Equipment Directives.