MITSUBISHI ELECTRIC MSZ-EX12NLB (01) PDF DOCUMENT

The symbols displayed on the MITSUBISHI ELECTRIC MSZ-EX12NLB indoor and/or outdoor unit have the following meanings:

WARNING (Risk of fire) A2L: This unit uses a flammable refrigerant. If refrigerant leaks and comes in contact with fire or a heating part, it will create harmful gas and there is a risk of fire.

Read the OPERATING INSTRUCTIONS carefully before operation: This symbol indicates that the operating instructions should be read carefully before using the unit.

Service personnel instructions: This symbol indicates that service personnel are required to carefully read the OPERATING INSTRUCTIONS and INSTALLATION MANUAL before operation.

Further information available: This symbol indicates that further information is available in the OPERATING INSTRUCTIONS, INSTALLATION MANUAL, and the like.

The following warnings must be observed for the MITSUBISHI ELECTRIC MSZ-EX12NLB to prevent death or serious injury:

Installation:

• Do not install the unit by yourself (user). Improper installation could cause fire, electric shock, injury, or water leakage. Consult a qualified installer.

• Follow the instructions in the installation manual. Incomplete installation could cause fire, electric shock, injury, or leakage of water.

• Use appropriate protective equipment and tools for safety during installation.

• Install the unit securely in a place that can bear its weight. If the location cannot bear the weight, the unit could fall and cause injury.

• Do not alter the unit, as it may cause fire, electric shock, injury, or water leakage.

• Fasten a flare nut with a torque wrench as specified. If too tight, the nut could break and cause refrigerant leakage.

• Install the unit according to national wiring regulations.

Electrical Safety:

• Perform electrical work according to the manual and use an exclusive circuit. Do not connect other appliances to the circuit.

• Ground the unit correctly. Do not connect the ground wire to a gas pipe, water pipe, lightning rod, or telephone ground.

• Do not damage the wires, as this could cause a fire.

• Shut off the main power when setting up the indoor P.C. board or wiring.

• Use specified wires to securely connect the indoor and outdoor units. Improper connection could cause fire.

• Do not use intermediate connections of the power cord or an extension cord. Do not connect many devices to one AC outlet.

• When plugging in the power supply, ensure there is no dust, blockage, or loose parts in the outlet or on the plug.

• Securely attach the electrical cover to the indoor unit and the service panel to the outdoor unit.

Refrigerant Safety:

• When installing, relocating, or servicing, ensure no substance other than the specified refrigerant (R454B) enters the refrigerant circuit.

• Do not discharge refrigerant into the atmosphere. Check for leaks after installation. If refrigerant leaks, ventilate the room.

• Use appropriate tools and piping materials for installation, as R454B pressure is 1.6 times higher than R22.

• When pumping down the refrigerant, stop the compressor before disconnecting the refrigerant pipes.

• Securely connect the refrigerant pipes before starting the compressor when installing the unit.

• When using a gas burner or other flame-producing equipment, completely remove all refrigerant from the air conditioner and ensure the area is well-ventilated.

• The appliance shall be stored in a room without continuously operating ignition sources (e.g., open flames, an operating gas appliance, or an operating electric heater).

• Do not pierce or burn the unit.

• Pipe-work shall be protected from physical damage.

To prevent serious injury when operating the MITSUBISHI ELECTRIC MSZ-EX12NLB, observe the following cautions:

• Depending on the installation area, install a Ground Fault Interrupt (GFI) circuit breaker to prevent electric shock.

• Perform the drainage/piping work securely according to the installation manual to prevent water from dripping from the unit and damaging household items.

• Do not touch the air inlet or the aluminum fins of the outdoor unit, as this could cause injury.

• Wear protective equipment when you touch the base of the outdoor unit to prevent injury.

• Do not install the outdoor unit where small animals may live. Small animals entering the unit could cause a malfunction, smoke emission, or fire. Keep the area around the unit clean.

The required tools for installing the MITSUBISHI ELECTRIC MSZ-EX12NLB are:

• Phillips head screwdriver

• Level

• Scale

• Utility knife or scissors

• 3 inches (75 mm) hole saw

• Torque wrench

• Wrench (or spanner)

• 5/32 inch (4 mm) hexagonal wrench

• Flare tool for R410A/R454B

• Gauge manifold for R410A/R454B

• Vacuum pump for R410A/R454B

• Charge hose for R410A/R454B

• Pipe cutter with reamer

The mounting height of the MITSUBISHI ELECTRIC MSZ-EX12NLB indoor unit shall be 5.9 feet (1.8 m) or more from the floor. Up to 7.5 feet (2.3 m) is recommended.

The unit must be installed in a room that exceeds the minimum room area (Amin) determined by the total refrigerant amount (M).

Choose a location that meets the following criteria:

• Where airflow is not blocked.

• Where cool (or warm) air spreads over the entire room.

• On a rigid wall to reduce the possibility of vibration.

• Where it is not exposed to direct sunlight.

• Where it can be easily drained.

• At least 3 feet (1 m) away from a TV and radio.

• In a place as far away as possible from fluorescent and incandescent lights.

• Where the air filter can be removed and replaced easily.

• Where it is away from other heat or steam sources.

The minimum room area (Amin) for the MITSUBISHI ELECTRIC MSZ-EX12NLB is determined by the total refrigerant amount (M) as shown in the table below.

Avoid the following places for installation of the MITSUBISHI ELECTRIC MSZ-EX12NLB where air conditioner trouble is liable to occur:

• Where flammable gas could leak.

• Where there is an excessive amount of machine oil in the air.

• Where oil is splashed or where the area is filled with oily smoke (such as cooking areas and factories).

• Salty places such as the seaside.

• Where sulfide gas is generated such as a hot spring, sewage, or waste water.

• Where there is high-frequency or wireless equipment.

• Where there is emission of high levels of VOCs, including phthalate compounds, formaldehyde, etc., which may cause chemical cracking.

• The appliance shall be stored so as to prevent mechanical damage from occurring.

Note for low outside temperature operation:

• Never install the outdoor unit where its air inlet/outlet side may be exposed directly to wind.

• To prevent wind exposure, install the outdoor unit with its air inlet side facing the wall and a baffle board on the air outlet side.

To prevent condensation, insulate the two refrigerant pipes. Be sure to use insulation of the specified thickness. The refrigerant pipe bending radius must be 4 inches (100 mm) or more.

1. Find a stud in the wall to attach installation plate (1) horizontally by tightening the fixing screws (2) firmly.

2. To prevent the installation plate from vibrating, be sure to install the attachment screws in the holes indicated in the illustration. For added support, additional screws may also be installed in other holes.

3. When the knockout is removed, apply vinyl tape to the knockout edges to prevent damaging the wires.

4. If the indoor unit is to be attached to a concrete wall using recessed bolts, secure the installation plate using the 7/16 inch x 13/16 inch – 7/16 inch x 1 inch (11 mm x 20 mm – 11 mm x 26 mm) oval hole (17-3/4 inches [450 mm] pitch).

5. If the recessed bolt is too long, change it for a shorter one (field-supplied).

1. Remove the panel assembly.

2. Place the upper part of the indoor unit on the installation plate.

3. Remove corner box R and electrical cover.

4. Remove display P.C. board holder, conduit cover and conduit plate.

5. Attach the appropriate joint (straight or elbow) to the conduit plate with a lock nut. The thread of the installed joint appearing inside should be less than 3/8 inch (10 mm).

6. Process the end of the ground wire and connect it to the ground terminal of the electrical parts box.

7. Process the end of the indoor/outdoor unit connecting wire and attach it to the terminal block. Ensure there is no mis-wiring and that the wire is attached securely.

8. Firmly tighten the terminal screws. After tightening, verify that the wires are tightly fastened.

9. Reinstall the conduit plate, conduit cover, and display P.C. board holder.

10. According to the piping direction, remove the shaded part of the corner box L or R. Reinstall the electrical cover, corner box, and front panel.

Pipe Forming General Instructions:

• Place the drain hose below the refrigerant piping.

• Make sure that the drain hose is not crowded or bent.

• Do not pull the hose when applying the tape.

• When the drain hose passes through the room, be sure to wrap it with insulation material (field-supplied).

Left or Left-Rear Piping:

1. Place the refrigerant piping and the drain hose together, then firmly apply felt tape (4) from the end.

2. Pull out the drain cap at the back right of the indoor unit.

3. Pull out the drain hose at the back left of the indoor unit.

4. Put the drain cap into the section where the drain hose was attached at the rear of the indoor unit.

5. Insert the drain hose fully into the drain pan at the back right of the indoor unit.

6. Insert the drain hose into the wall hole sleeve (C), and attach the upper part of the indoor unit onto the installation plate. Then, shift the indoor unit completely to the left to make placing the piping in the back of the unit easier.

7. Use two pieces of cardboard from the shipping box as spacers to lift the indoor unit.

8. Connect the refrigerant piping with the extension pipe (B).

9. Attach the lower part of the indoor unit into the installation plate (1).

Drain Piping Guidelines:

• If the extension drain hose has to pass through a room, be sure to wrap it with insulation (field-supplied).

• The drain hose should point downward for easy drainage.

• If the provided drain hose is too short, connect it with a field-supplied drain hose.

• When connecting to a hard vinyl chloride pipe, insert it securely into the pipe.

• Make sure no stress is applied to the connecting portion of the drain hose after installation.

1. Cut the copper pipe as straight as possible with a pipe cutter.

2. Remove all burrs from the cut section of the pipe, ensuring no metal shavings get into the piping.

3. Remove flare nuts attached to the indoor and outdoor units, then put them on the pipe.

4. Perform the flaring work. Firmly hold the copper pipe in the dimension shown in the tightening torque table.

5. Check the flared work. If it is defective, cut off the section and repeat the procedure.

Fasten the flare nut with a torque wrench as specified in the torque table. When fastened too tight, the flare nut may break and cause a refrigerant leakage. Be sure to wrap insulation around the piping to prevent burns or frostbite.

Indoor Unit Connection:

• Connect both liquid and gas piping to the indoor unit.

• Do not apply refrigeration oil on screw threads. Excessive tightening will damage the screw.

• To connect, first align the center, then tighten the first 3 to 4 turns of the flare nut by hand.

• Use the tightening torque table as a guideline and tighten using two wrenches. Excessive tightening damages the flare section.

Outdoor Unit Connection:

• Connect pipes to the stop valve pipe joint of the outdoor unit following the same procedure as the indoor unit connection.

• For tightening, use a torque wrench or spanner.

1. Connect the testing tools. Ensure the stop valves are closed.

2. Add pressure to the refrigerant lines through the service port of the stop valve for GAS. Pressurize to 601 psig (4.15 MPa) and measure the surrounding temperature and refrigerant pressure. Add pressure gradually, not all at once.

3. If the specified pressure holds for about one day and does not decrease, the pipes have passed the test and there are no leaks. Note that if the surrounding temperature changes by 1°F (0.5°C), the pressure will change by about 1 psig (0.007 MPa). Make necessary corrections.

4. If the pressure decreases, there is a gas leak. Look for the source of the gas leak.

1. Insert the power supply plug into the power outlet and/or turn on the breaker.

2. Press the Emergency Operation Switch (E.O. SW) once for COOL, and twice for HEAT operation. The test run will be performed for 30 minutes. If the left lamp of the operation indicator blinks every 0.5 seconds, inspect the indoor/outdoor unit connecting wire for mis-wiring. After the test run, emergency mode (set temperature 75°F [24°C]) will start.

3. To stop operation, press the E.O. SW several times until all LED lamps turn off.

The MITSUBISHI ELECTRIC MSZ-EX12NLB is equipped with an auto restart function. When the power supply is cut off during operation, such as during a blackout, the function automatically starts operation in the previous setting once the power supply is resumed.

Caution: After a test run or remote signal reception check, turn off the unit with the E.O. SW or the remote controller before turning off the power supply. If this procedure is not performed, the unit will automatically begin operation when the power supply is resumed.

If the auto restart function is unnecessary, it can be deactivated by consulting a service representative.

When breaking into the refrigerant circuit of the MITSUBISHI ELECTRIC MSZ-EX12NLB for repairs or other purposes, it is important that best practice is followed since flammability is a consideration. The following procedure shall be adhered to:

• remove refrigerant

• purge the circuit with inert gas

• evacuate

• purge again with inert gas

• open the circuit by cutting or brazing.

The refrigerant charge must be recovered into the correct recovery cylinders. For appliances containing flammable refrigerants, the system shall be “flushed” with OFN to render the unit safe. This process may need to be repeated several times. Compressed air or oxygen must not be used for purging refrigerant systems.

Removal procedure:

1. Unlock the upper and lower vanes using a thin instrument. Then, remove the horizontal vanes.

2. Remove the 2 screws which fix the panel assembly.

3. Remove the panel assembly. Be sure to remove its bottom right end first.

Installation procedure:

1. Install the panel assembly following the removal procedure in reverse.

2. Be sure to press the positions as indicated by the arrows in order to attach the assembly completely to the unit.

3. Install the horizontal vanes.

Remove the bottom of the MITSUBISHI ELECTRIC MSZ-EX12NLB indoor unit from the installation plate. When releasing the corner part, release both the left and right bottom corner part of the indoor unit and pull it downward and forward as shown in the figure in the manual.

Connect the interface to the indoor control P.C. board of the MITSUBISHI ELECTRIC MSZ-EX12NLB with the connecting cable. Note that cutting or extending the cable may result in connection defects. Keep the connecting cable as far as possible from the power supply cord, connecting wire, and ground wire.

1. Remove the panel and the lower right corner box.

2. Open the covers of the indoor control P.C. board.

3. Join the connecting cable to CN105 on the indoor control P.C. board.

4. Attach the cable clamp provided with the interface to the thick part of the connecting cable with a screw 4×16.

5. Hook the connecting cable into the ribs as shown in the figure.

6. Close the covers of the indoor control P.C. board. Be careful not to catch the thin part of the connecting cable in the cover. Reinstall the panel and the lower right corner box.