MITSUBISHI ELECTRIC MSZ-HM18, 24NA Split Type Air Conditioner Installation Guide

*3 When any 2 sides of left, right and rear of unit are clear.

Drain piping for outdoor unit
Install the unit horizontally. Do not use drain socket in cold regions. Drain may freeze and make the fan stop. The outdoor unit produces condensate during the heating operation. Select the installation place to ensure to prevent the outdoor unit and/or the grounds from being wet by drain water or damaged by frozen drain water.

INDOOR UNIT INSTALLATION

1. ATTACHING THE INSTALLATION PLATE

   • Find a stud in the wall to attach installation plate (1) horizontally by tightening the fixing screws (2) firmly.
   • To prevent installation plate (1) 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. When the indoor unit is to be attached to a concrete wall using recessed bolts, secure installation plate (1) using 7/16 in. x 13/16 in. • 7/16 in. x 1 in. (11 mm x 20 mm • 11 mm x 26 mm) oval hole (17-3/4 in. [450 mml pitch).
   • If the recessed bolt is too long, change it for a shorter one (field-supplied).

2. DRILLING

3. Determine where the holes will be located on the wall.

4.  Drill a o 3 in. (75 mm) hole. The outdoor side should be 6/32 to 9/32 in. (5 to 7 mm) lower than the indoor side.

5. Insert wall hole sleeve (C).

6. CONNECTING WIRES FOR INDOOR UNIT
   Note: When the indoor unit is powered from the outdoor unit, depending on local code, a disconnect switch needs to be installed to a power supply circuit.

7. Remove the panel assembly. (Refer to 5-1.)

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

9. Remove corner box R and electrical cover.

10. Remove indoor control P.C. board holder, conduit cover and conduit plate.

11. Attach conduit pipe (for rear piping) / elbow joint (for right, left, or downward piping) to conduit plate with lock nut. The thread of the installed conduit pipe / elbow joint appearing inside should be less than 3/8 in. (10 mm). (Fig. 1) Elbow joint should appear less than 1-3/16 in. (30 mm) outside. (Fig. 2)

12. Process the end of ground wire (Fig. 3). Connect it to the ground terminal of electrical parts box.

13. Process the end of indoor/outdoor unit connecting wire (A) (Fig. 3). Attach it to the terminal block. Be careful not to make mis-wiring. Attach the wire to the terminal block securely so that its core cannot be seen, and no external force affects the connecting section of the terminal block.

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

15. Reinstall conduit plate, conduit cover and indoor control P.C. board holder.

16. According to the piping direction, remove the shaded part of the corner box L (Fig. 4) or corner box R (Fig. 5). Reinstall electrical cover, corner box and front panel.

Remark : A disconnect switch should be required. Check the local code. ** Use a ring tongue terminal in order to connect a ground wire to terminal.

PIPE FORMING AND DRAIN PIPING

1. PIPE FORMING
   • 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 the room, be sure to wrap it with insulation material (field- supplied).
     Note: Make sure not to damage the cover of refrigerant pipe when attaching it back on with screws.

Left or left-rear piping
Note: Be sure to reattach the drain hose and the drain cap if the piping is being installed on left or bottom left of unit, otherwise, water could drip down from the drain hose.

1. Place the refrigerant piping and the drain hose together, then firmly apply felt tape (4) from the end. Felt tape (4) overlap width should be 1/3 the tape width. Use a bandage stopper at the end of felt tape (4).
2. Pull out the drain cap at the back right of the indoor unit. (Fig. 1)
   • Hold the convex section at the end and pull the drain cap.
3. Pull out the drain hose at the back left of the indoor unit. (Fig. 2)
   • Hold the claw marked by the arrows and pull out the drain hose forward.
4. Put the drain cap into the section to which the drain hose is to be attached at the rear of the indoor unit. (Fig. 3)
   • Insert a screwdriver into the hole on the cap and insert the cap fully into the drain pan.
5. Insert the drain hose fully into the drain pan at the back right of the indoor unit. (Fig. 4)
   • Check if the hose is hooked securely to the projection of its inserting part at the drain pan.
6. Insert the drain hose into wall hole sleeve (C), and attach the upper part of indoor unit onto the installation plate (1). Then, shift the indoor unit completely to the left to make placing the piping in the back of the unit easier.
7. Cut out a piece of cardboard from the shipping box, roll it up, hook it onto the back rib, and use it as a spacer to lift the indoor unit. (Fig. 5)
8. Connect the refrigerant piping with the extension pipe (B).
9. Attach the lower part of the indoor unit into the installation plate (1).

Rear or bottom piping

1. Place the refrigerant piping and the drain hose together, then firmly apply piping tape (G) from the end.
2. Insert the piping and the drain hose into the wall hole sleeve (C), and attach the upper part of the indoor unit on the installation plate (1).
3. Check if the indoor unit is attached securely on the installation plate (1) by moving the unit to left and right.
4. Attach the lower part of the indoor unit into the installation plate (1).

Right piping
Note: Before performing the following, make sure that wiring is completed, and the conduit cover is installed. (Refer to 2-3.)

1. Place the refrigerant piping and the drain hose together, shift them to left side of the unit, and then firmly apply piping tape (G) from the end.
2. Insert the piping and the drain hose into the wall hole sleeve (C), and attach the upper part of the indoor unit on the installation plate (1).
3. Check if the indoor unit is attached securely on the installation plate (1) by moving the unit to left and right.
4. Attach the lower part of the indoor unit into the installation plate (1).

DRAIN PIPING

• 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 drain. (Fig. 1)
• If the drain hose provided with the indoor unit is too short, connect it with a field-supplied drain hose (1). (Fig. 2)
• When connecting the drain hose to a hard vinyl chloride pipe, be sure to insert it securely into the pipe. (Fig. 3)

OUTDOOR UNIT INSTALLATION

• CONNECTING WIRES FOR OUTDOOR UNIT
  1. Remove the service panel.
  2. Remove the conduit cover.
  3. Attach the conduit connectors to the conduit plate with lock nuts then secure it against unit with screws.
  4. Connect the ground wires of indoor/outdoor unit connecting wire (A) and power supply cord (K) to the TB support.
  5. Loosen the terminal screws, then attach indoor/outdoor unit connecting wire (A) and power sup- ply cord (K) from the indoor unit correctly to the terminal block. Attach the wires to the terminal block securely so that the cores cannot be seen, and no external force affects the connecting section of the terminal block.
  6. Firmly tighten the terminal screws. After tightening, verify that the wires are tightly fastened.
  7. Install the conduit cover.
  8. Install the service panel securely.
•  Make ground wire a little longer than others. (More than 4 in. [100 mm])
• For future servicing, leave some slack in the connecting wires.
• Be sure to attach each screw to its correspondent terminal when securing the cord and/or the wire to the terminal block.

FLARE CONNECTION

1. Cut the copper pipe as straight as possible with a pipe cutter. (Fig. 1, 2)
2. Remove all burrs from the cut section of the pipe, ensuring that precautions are taken to avoid getting metal shavings into the piping. (Fig. 3)
3. Remove flare nuts attached to indoor and outdoor units, then put them on pipe.
4. Flaring work (Fig. 4, 5). Firmly hold copper pipe in the dimension shown in the table. Select A inch (mm) from the table according to the tool you use.
5. Check • Compare the flared work with Fig. 6. • If flare is defective, cut off the section and repeat procedure.

PIPE CONNECTION

• Fasten flare nut with a torque wrench as specified in the table (refer to 3-2.).
• When fastened too tight, flare nut may eventually break and cause refrigerant leakage.
• Be sure to wrap insulation around the piping. Direct contact with the bare piping may result in burns or frostbite.

Indoor unit connection
Connect both liquid and gas piping to indoor un

• Apply a thin coat of refrigeration oil (J) on the flared ends of the pipes. Do not apply refrigeration oil on screw threads. Excessive tightening torque will result in damage on the screw.
• To connect, first align the center, then tighten the first 3 to 4 turns of flare nut.
• Use tightening torque table above as a guideline for indoor unit side joints, and tighten using two wrenches. Excessive tightening damages the flare section.
• Be sure to wrap insulation around the piping. Direct contact with the bare piping may result in burns or frostbite.

Outdoor unit connection

• Connect pipes to stop valve pipe joint of the outdoor unit following the same procedure detailed in Indoor unit connection.
• For tightening, use a torque wrench or spanner.

WARNING
When installing the unit, securely connect the refrigerant pipes before starting the compressor.

INSULATION AND TAPING

1. Cover piping joints with pipe cover.
2. For outdoor unit side, insulate the piping, including valves.
3. Apply piping tape (G) starting from the connection on the outdoor unit.
   When piping has to be installed through a ceiling, closet or where the temperature and humidity are high, use additional field-supplied insulation to prevent condensation.

PURGING PROCEDURES, LEAK TEST, AND TEST RUN

PURGING PROCEDURES AND LEAK TEST

1. Remove service port caps from stop valves on both sides of refrigerant lines. (The stop valves are fully closed when shipped.) Leave closed.
2. Connect gauge manifold to ports of stop valves.
3. Evacuate the system to 4000 microns from both service valves. System manifold gauge: must not be used to measure vacuum. A micron gauge must be used at all times. Brea the vacuum with Nitrogen(N2) into the discharge service valve to 0 PSIG.
4. Evacuate the system to 1500 microns. Break the vacuum with Nitrogen(N2) into this discharge service valve to 0 PSIG.
5. Evacuate the system to 500 microns.
6. Close gauge manifold valves, stop the pump, and conduct a 30 minute rise test.
7. System should hold 500 microns for a minimum of 1 hour
8. Fully open all stop valves on both sides of gas pipe and liquid pipe. Operating without fully opening lowers the performance and this causes trouble
9. Refer to 1-3 and charge the prescribed amount of additional refrigerant if needed. B sure to charge slowly with liquid refrigerant. Otherwise composition of the refrigerant i the system may be changed and affect performance of the air conditioner
10. Remove gauge manifolds and replace service port caps and tighten.
11. Leak test

TEST RUN

1. Insert power supply plug into the power outlet and/or turn on the breaker.
2. Press the E.O. SW once for COOL, and twice for HEAT operation. Test run will be performed for 30 minutes. If the upper lamp of the operation indicator blinks every 0.5 seconds, inspect the indoor/outdoor unit connecting wire (A) 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. Refer to operating instructions for details.

Checking the remote (infrared) signal reception
Press the ON/OFF button on the remote controller (3) and listen for an audible indicator from the indoor unit. Press the ON/OFF button again to turn the air conditioner off.
Once the compressor stops, the restart preventive device operates so the compressor will not operate for 3 minutes to protect the air conditioner.

AUTO RESTART FUNCTION
This product is equipped with an auto restart function. When the power supply is cut off during operation, such as during blackouts, the function automatically starts operation in the previous setting once the power supply is resumed. (Refer to the operating instructions for details.)

Caution:

• After 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 power supply is resumed.

To the user

• After installing the unit, explain to the user about auto restart function.
• If auto restart function is unnecessary, it can be deactivated. Consult the service representative to deactivate the function. Refer to the service manual for details.

EXPLANATION TO THE USER

• Using the OPERATING INSTRUCTIONS, explain to the user how to use the air conditioner (the remote controller, removing the air filters, placing or removing the remote controller from the remote controller holder, cleaning methods, precautions for operation, etc.)
• Recommend that the user read the OPERATING INSTRUCTIONS carefully.

RELOCATION AND MAINTENANCE

REMOVING AND INSTALLING THE PANEL ASSEMBLY
Removal procedure

1. Open the front panel.
2. Remove the 3 screws which fix the panel assembly.
3. Close the front panel.
4. Remove the panel assembly. Be sure to remove its bottom 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.

REMOVING THE INDOOR UNIT
Remove the bottom of the indoor unit from the installation plate. When releasing the corner part, release both left and right bottom corner part o indoor unit and pull it downward and forward as shown in the figure on the righ

PUMPING DOWN

When relocating or disposing of the air conditioner, pump down the system following the procedure below so that refrigerant is not released into the atmosphere.

1. Connect the gauge manifold valve to the service port of the stop valve on the gas pipe side of the outdoor unit.
2. Fully close the stop valve on the liquid pipe side of the outdoor unit.
3. Close the stop valve on the gas pipe side of the outdoor unit almost completely so that it can be easily closed fully when the pressure gauge shows 0 psi [Gauge] (0 Mpa).
4. Start the emergency COOL operation. To start the emergency operation in COOL mode, disconnect the power supply plug and/or turn off the breaker. After 15 seconds, connect the power supply plug and/ or turn on the breaker, and then press the E.O. SW once. (The emergency COOL operation can be performed continuously for up to 30 minutes.)
5. Fully close the stop valve on the gas pipe side of the outdoor unit when the pressure gauge shows (0.1 to 0 psi [Gauge] (0.05 to 0 Mpa)).
6. Stop the emergency COOL operation. To stop operation, press the E.O. SW several times until all LED lamps turn off. Refer to operating instructions for details.

WARNING
When pumping down the refrigerant, stop the compressor before disconnecting the refrigerant pipes. The compressor may burst if air etc. get into it.

MITSUBISHI ELECTRIC CORPORATION HEAD OFFICE: TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN

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