Mitsubishi Electric City Multi Indoor Unit Installation Manual

Introduction

For safe and correct use, please read this installation manual thoroughly before installing the air-conditioner unit.

1. Safety Precautions

1.1. Before installation and electric work

WARNING (Risk of fire): This symbol is only for R32 refrigerant. R32 refrigerant is flammable. If it leaks or contacts fire/heat-generating parts, it may create harmful gas and pose a risk of fire. Read the OPERATION MANUAL carefully before operation. Service personnel are required to carefully read the OPERATION MANUAL and INSTALLATION MANUAL before operation.

Symbols used in the text:

• Warning: Describes precautions to prevent danger of injury or death.
• Caution: Describes precautions to prevent damage to the unit.

Symbols used in the illustrations:

• ❌: Indicates an action that must be avoided.
• ❗: Indicates that important instructions must be followed.
• ⏚: Indicates a part which must be grounded.
• ⚠️: Indicates caution with rotating parts (displayed on main unit label, yellow).
• ⚡: Beware of electric shock (displayed on main unit label, yellow).

Warning: Carefully read the labels affixed to the main unit.

Warning:

• Do not install it by yourself (customer). Incomplete installation could cause injury due to fire, electric shock, unit falling, or water leakage. Consult the dealer or a special installer.
• Ask an authorized technician to install the air conditioner. Improper installation may result in water leakage, electric shock, or fire.
• Install the unit at a place that can withstand its weight. Inadequate strength may cause the unit to fall, resulting in injuries.
• Use specified cables for wiring. Make connections securely so that external force is not applied to terminals. Inadequate connection may generate heat and cause fire.
• Prepare for typhoons, strong winds, and earthquakes and install the unit at the specified place. Improper installation may cause the unit to topple and result in injury.
• Always use accessories specified by Mitsubishi Electric. Ask an authorized technician for installation. Improper installation may result in water leakage, electric shock, or fire.
• Never repair the unit yourself. Consult the dealer for repairs. Improper repairs may result in water leakage, electric shock, or fire.
• Do not touch heat exchanger fins. Improper handling may result in injury.
• When handling, wear protective equipment (gloves, boiler suit, safety glasses). Improper handling may result in injury.
• If refrigerant gas leaks during installation, ventilate the room. Contact with flame may release poisonous gases.
• Install according to this manual. Improper installation may result in water leakage, electric shock, or fire.
• Have all electrical work done by a licensed electrician according to standards and this manual. Use a special circuit. Inadequate power or improper work may result in electric shock or fire.
• Use only provided or specified parts. Defective parts may cause injury, water leakage, fire, electric shock, or unit falling.
• Keep electrical parts away from water. This may result in electric shock, fire, or smoke.
• When installing/relocating/servicing, use only the specified refrigerant. Do not mix refrigerants or allow air in lines. Mixing air may cause abnormal pressure, explosion, or hazards. Using incorrect refrigerant may cause mechanical failure, malfunction, or breakdown, potentially violating laws.
• Mitsubishi Electric Corporation is not responsible for malfunctions/accidents due to wrong refrigerant.
• Install indoor unit in a room equal to or larger than specified in the outdoor unit manual.
• Use only manufacturer-recommended means for defrosting or cleaning.
• Store the indoor unit in a room without continuously-operating ignition devices (open flame, gas appliance, electric heater).
• Do not pierce or burn the unit or refrigerant lines.
• Be aware refrigerant may be odorless.
• Pipe-work shall be protected from physical damage.
• Keep pipe-work installation to a minimum.
• Observe national gas regulations.
• Keep ventilation openings clear.
• Do not use low-temperature solder alloy when brazing refrigerant pipes.
• Ventilate room sufficiently during brazing. Ensure no hazardous/flammable materials are nearby.
• In closed/small rooms, check for refrigerant leaks before work. Leaks may ignite or release poisonous gases.
• If installed in a small/closed room, take measures to prevent refrigerant concentration from exceeding safety limits. Consult dealer. Exceeding limits may cause hazards due to lack of oxygen.
• Store appliance to prevent mechanical damage.
• For installation/relocation, follow manual instructions and use specific tools/components for the specified refrigerant.
• When moving/reinstalling, consult dealer or authorized technician. Improper installation may result in water leakage, electric shock, or fire.
• After installation, check for refrigerant leaks. Leaks exposed to heat sources may generate noxious gases.
• Do not reconstruct or change protection device settings. Tampering may cause fire or explosion.
• Dispose of product through your dealer.
• Do not use a leak detection additive.
• If supply cord is damaged, it must be replaced by manufacturer, service agent, or qualified persons to avoid hazard.
• Servicing only as recommended by manufacturer.
• Appliance not for use by persons with reduced capabilities unless supervised. Children should be supervised.
• Installer/specialist must secure safety against leakage according to local regulations. Manual instructions apply if local regulations are unavailable.
• Pay special attention to places like basements where refrigerant gas can stay (heavier than air).
• Intended for expert/trained users in shops, light industry, farms, or commercial use.

1.2. Precautions for devices that use R32 refrigerant

Caution:

• Do not use existing refrigerant piping. Old refrigerant/oil contains chlorine that deteriorates new unit's oil.
• Use piping made of C1220 (Cu-DHP) phosphorus deoxidized copper (JIS H3300). Ensure inner/outer surfaces are clean and free of contaminants. Contaminants may deteriorate oil.
• Store piping indoors and seal ends until just before brazing. If dust/dirt/water enters, oil deteriorates and compressor may fail.
• Use liquid refrigerant to fill the system. Gas refrigerant may change composition and reduce performance.
• Do not use refrigerant other than R32. Other refrigerants may cause oil deterioration.
• Use a vacuum pump with a reverse flow check valve. Pump oil may flow back and deteriorate refrigerator oil.
• Do not use tools for conventional refrigerants (gauge manifold, charge hose, leak detector, etc.). Mixing may deteriorate refrigerant/oil. R32 does not react with conventional leak detectors.
• Do not use a charging cylinder. May cause refrigerant deterioration.
• Be careful when managing tools. Dust/dirt/water may cause refrigerant deterioration.

1.3. Before getting installed

Caution:

• Do not install where combustible gas may leak. Accumulation may cause explosion.
• Do not use where food, pets, plants, precision instruments, or artwork are kept. Quality may deteriorate.
• Do not use in special environments (oil, steam, sulfuric smoke). Performance may reduce or parts may be damaged.
• In hospitals, communication stations, etc., provide protection against electromagnetic noise. Inverters, generators, medical equipment may cause erroneous operation or fail. Air conditioner may affect such equipment.
• Do not install on a structure that may cause leakage. High humidity (>80%) or clogged drain may cause condensation drip. Perform collective drainage.
• Install indoor models at least 2.5 m above floor.
• Do not install above cooking or food processing areas.

1.4. Before getting installed (moved) - electrical work

Caution:

• Ground the unit. Do not connect ground wire to gas/water pipes, lightning rods, or telephone lines. Improper grounding may cause electric shock.
• Install power cable without tension. Tension may cause cable break, heat, and fire.
• Install a leak circuit breaker. Lack of it may cause electric shock.
• Use power line cables of sufficient capacity and rating. Undersized cables may leak, heat, and cause fire.
• Use only specified capacity breaker and fuse. Larger capacity may cause malfunction or fire.
• Do not wash electrical parts. May cause electric shock.
• Ensure installation base is not damaged by long use. Damage may cause unit to fall, leading to injury or property damage.
• Install drain piping correctly with thermal insulation to prevent condensation. Improper piping may cause water leakage and damage.
• Be careful during transportation. Do not carry products over 20 kg alone. Do not use PP bands for transportation.
• Do not touch heat exchanger fins. May cut fingers.
• Dispose of packing materials safely. Nails/metal parts may cause stabs. Tear plastic bags to prevent suffocation risk for children.

1.5. Before starting the test run

Caution:

• Turn on power at least 12 hours before starting operation. Immediate start-up can cause severe damage to internal parts. Keep power switch on during operational season.
• Do not touch switches with wet fingers. Can cause electric shock.
• Do not touch refrigerant pipes during or immediately after operation. They may be hot or cold, causing burns or frostbite.
• Do not operate with panels and guards removed. Rotating, hot, or high-voltage parts can cause injuries.
• Do not turn off power immediately after stopping operation. Wait at least five minutes. Otherwise, water leakage and trouble may occur.

2. Indoor unit accessories

The unit is provided with the following accessories:

3. Selecting an installation site

• Select a site with a sturdy fixed surface durable against the unit's weight.
• Determine the routing for carrying the unit to the site before installation.
• Select a site not affected by entering air.
• Select a site where the flow of supply and return air is not blocked.
• Select a site where refrigerant piping can easily be led outside.
• Select a site allowing full distribution of supply air in the room.
• Do not install where oil splashing or steam is present in large quantities.
• Do not install where combustible gas may generate, flow, stagnate, or leak.
• Do not install where equipment generating high frequency waves (e.g., high frequency welder) is present.
• Do not install where a fire detector is located at the supply air side (may operate erroneously due to heated air).
• If special chemical products may scatter (e.g., chemical plants, hospitals), conduct a full investigation. Plastic components may be damaged.
• If the unit runs for long hours with high temperature/humidity above the ceiling (dew point > 26°C), condensation may form. Add 10-20 mm insulation to the entire surface of the indoor unit to avoid condensation.

3.1. Install the indoor unit on a ceiling strong enough to sustain its weight

Warning: The unit must be securely installed on a structure that can sustain its weight. If mounted on an unstable structure, it may fall, causing injuries.

• Install in rooms exceeding the floor space specified in the outdoor unit installation manual.
• Install at least 2.5 m above floor or ground level. The unit should not be accessible to the general public.
• Refrigerant pipe connections shall be accessible for maintenance.

3.2. Securing installation and service space

Secure enough access space for maintenance, inspection, and replacement of motor, fan, drain pump, heat exchanger, and electric box. Choose one of the following methods:

• (1) When 300 mm or more space is available below the unit: (See Fig. 3.2.1) Create access doors 1 and 2 (450 x 450 mm each) as shown in Fig. 3.2.2. (Access door 2 is not required if enough space is available below for maintenance.)
• (2) When less than 300 mm space is available below the unit (at least 20 mm space): (See Fig. 3.2.3) Create access door 1 diagonally below the electric box and access door 3 below the unit (Fig. 3.2.4), OR create access door 4 below the electric box and the unit (Fig. 3.2.5).

Diagram Description (Figs. 3.2.1 - 3.2.5): These diagrams illustrate installation space requirements and the placement of access doors around the indoor unit. They show dimensions for ceiling clearance, access door sizes (e.g., 450 mm x 450 mm), and minimum required distances (e.g., Min. 300 mm, Min. 2500 mm). Labels indicate components like 'Electric box', 'Ceiling beam', 'Access door 1-4', 'Supply air', 'Intake air', and 'Bottom of indoor unit'.

3.3. Combining indoor units with outdoor units

For connecting indoor units with outdoor units, refer to the outdoor unit installation manual.

4. Fixing hanging bolts

4.1. Fixing hanging bolts

Diagram Description (Fig. 4.1.1): This diagram shows the dimensions (W, L, X, Y, Z) and the center of gravity for the indoor unit, relevant for hanging bolt placement.

Hanging structure:

• Ceiling: Ceiling structure varies. Consult your construction company for details.
• If necessary, reinforce hanging bolts with anti-quake supporting members. Use M10 bolts and members (field supply).

Values in parentheses are for the PEFY-M-VMAL-A1 model.

5. Installing the unit

5.1. Hanging the unit body

• Bring the indoor unit to the installation site while packed.
• Use a lifting machine to lift the unit and pass it through the hanging bolts.

Diagram Description (Fig. 5.1.1): Shows the 'Unit body' and 'Lifting machine' for hanging.

Diagram Description (Fig. 5.1.2): Shows components for hanging: 'Nuts (field supply)', 'Washers (field supply)', and 'M10 hanging bolt (field supply)'.

5.2. Confirming the unit's position and fixing hanging bolts

• Ensure hanging bolt nuts are tightened to fix the bolts.
• To ensure proper drain discharge, hang the unit level using a level.

Caution: Install the unit horizontally. If the drain port side is higher, water leakage may occur.

6. Refrigerant pipe and drain pipe specifications

To prevent condensation, provide sufficient antisweating and insulating work for refrigerant and drain pipes.

When using commercially available refrigerant pipes, wind insulating material (heat-resistant temperature > 100°C) onto liquid and gas pipes.

Insulate all indoor pipes with form polyethylene insulation (density 0.03) with thickness as specified below:

If the unit is used on the highest story or in high temperature/humidity conditions, use larger pipe sizes and thicker insulation. Follow customer specifications if provided.

6.1. Refrigerant pipe and drain pipe specifications

6.2. Refrigerant pipe, drain pipe

Diagram Description (Fig. 6.2.1): This diagram shows the connections for refrigerant pipes (liquid and gas) and drain pipes (standard and spontaneous draining) to the indoor unit.

7. Connecting refrigerant pipes and drain pipes

7.1. Refrigerant piping work

This work must follow installation manuals for the outdoor unit and BC controller. Series R2 systems branch at the BC controller. Refer to the outdoor unit manual for pipe length and elevation difference constraints. Connection is by brazing.

Caution: Install refrigerant piping as follows:

1. Cut the indoor unit piping tip, remove gas, then remove brazed cap.
2. Pull out thermal insulation on site piping, braze unit piping, and replace insulation. Wrap piping with insulating tape.

Diagram Description (Fig. 7.1.1): Shows where to cut the pipe (liquid pipe only) and remove the brazed cap.

Note: When brazing, cover pipes with a wet cloth to prevent burning/shrinking.

Diagram Description (Fig. 7.1.2): Illustrates cooling with a wet cloth during brazing.

Pay attention when wrapping copper piping, as it may cause condensation.

Diagram Description (Fig. 7.1.3): Shows steps for insulation: 'Thermal insulation', 'Pull out insulation', 'Wrap with damp cloth', 'Return to original position', 'Ensure no gap', 'Wrap with insulating tape'.

Cautions On Refrigerant Piping:

• Use non-oxidative brazing to prevent foreign matter/moisture entry.
• Apply refrigerating machine oil to flare connection seating surface and tighten with a double spanner.
• Provide a metal brace 50 cm from the connection to support the pipe, preventing load on the indoor unit end pipe.

Warning: Do not use refrigerant other than specified. Doing so may cause bursting, explosion, or fire, and may violate laws.

Caution: Use C1220 (Cu-DHP) copper piping. Ensure pipes are clean. Never use existing piping. Store piping indoors, sealed, until brazing. If dust/dirt/water enters, oil deteriorates and compressor may fail. Refrigerant is hygroscopic and degrades oil.

7.2. Drain piping work

• Ensure drain piping has a downward slope (> 1/100) to the outdoor side. No traps or irregularities.
• Cross-wise drain piping should be less than 20 m (excluding elevation difference). Use metal braces for long pipes. Never use an air vent pipe.
• Use hard vinyl chloride pipe VP-25 (O.D. 32 mm) for drain piping.
• Ensure collected pipes are 10 cm lower than the unit's drain port.
• Do not provide an odor trap at the drain discharge port.
• Place drain piping end where no odor is generated.
• Do not place drain piping end in drains with ionic gases.

Diagram Description (Fig. 7.2.1): Illustrates correct and incorrect piping for drain and refrigerant lines, showing insulation requirements, slope, support, air bleeders, and grouped piping options. It details pipe sizes (O.D. Ø32 PVC TUBE, O.D. Ø38 PVC TUBE for grouped piping) and minimum insulation thickness.

For PEFY-M-VMA model:

1. Insert drain socket (accessory) into drain port (32mm margin). Attach with glue, fix with band.
2. Attach drain pipe (O.D. Ø32 PVC TUBE PV-25, field supply). Attach with glue, fix with band.
3. Insulate drain pipe and socket (including elbow).
4. Check drainage (Refer to Fig. 7.3.1).
5. Attach insulating material and fix with band (large, accessory) to insulate drain port.

Diagram Description (Fig. 7.2.2): Details components for the PEFY-M-VMA-A1 model: 'Indoor unit', 'Tie band (accessory)', 'Visible part', 'Insertion margin', 'Drain socket (accessory)', 'Drain pipe (O.D. Ø32 PVC TUBE, field supply)', 'Insulating material (field supply)'.

For PEFY-M-VMAL model:

1. Insert drain socket (accessory) into drain port. Fix with accessory band (do not adhere).
2. Attach drain pipe (O.D. Ø32 PVC TUBE, field supply). Attach with glue, fix with band.
3. Insulate drain pipe and socket (including elbow).

Diagram Description (Fig. 7.2.3): Details components for the PEFY-M-VMAL-A1 model: 'Indoor unit', 'Tie band (accessory)', 'Band fixing part', 'Insertion margin', 'Drain socket (accessory)', 'Drain pipe (O.D. Ø32 PVC TUBE, field supply)', 'Insulating material (field supply)'.

7.3. Confirming drain discharge

• Ensure drain-up mechanism operates normally and no water leaks from connections. Confirm before ceiling work.
• Remove water supply port cover. Fill water into feed water pump using a tank. Place pump/tank end in a drain pan to prevent overflow.
• Perform test run in cooling mode or connect SWE connector to ON. (Drain pump and fan operate without remote controller). Use a transparent hose to check discharge. Turn back to former state after work.
• After confirmation, cancel test run mode and turn off main power. Disconnect SWE connector from ON, connect to OFF, and reattach water supply port cover.

Diagram Description (Fig. 7.3.1): Shows steps for drain discharge confirmation: inserting pump end, removing water supply port, water quantity, filling port, and screw.

Diagram Description (Fig. 7.3.2): Shows the '' with SWE connector.

8. Duct work

• Insert canvas duct between unit and duct.
• Use incombustible material for duct parts.
• Provide full insulation to inlet/outlet duct flanges to prevent condensation.
• Change air filter position for serviceability.

Diagram Description (Fig. 8.0.1): Illustrates duct connection options: ' In case of rear inlet' and ' In case of bottom inlet'. Labels include 'Duct', 'Air inlet', 'Canvas duct', 'Access door', 'Air outlet', 'Ceiling surface', and minimum distance requirements.