MITSUBISHI ELECTRIC NAXWST18B112A Split Type Air Conditioners Instruction Manual

5

(3)| Wireless remote controller| 1
(4)| Felt tape (For left or left-rear piping)| 1
(5)| Remote controller holder| 1
(6)| Screws for the remote controller holder
3.5 × 16 mm (Black)|

2

(7)| Battery (AAA) for (3)| 2
(8)| Air cleaning filter| 2

Note:

*1 Place indoor/outdoor unit connecting wire (A) and power supply cord (K) at least 3 feet (1 m) away from the TV antenna wire.
Units should be installed by licensed contractor according to local code requirements.

Use the wall hole sleeve (C) to prevent indoor/outdoor connecting wire (A) from contacting metal parts in the wall and to protect the wiring from rodents.

Note:

• The dimensions indicated in the arrows ( ) above show the required space to guarantee performance of the air conditioner. Install the outdoor unit where the maximum possible space can be provided, considering later relocation, services, or repairs.
• The cooling/heating performance and the efficiency of power usage may fall about 10% at the place where short cycle is likely occur due to poor ventilation. Installing the air outlet guide (optional) can improve performances.
• If air from the outlet blows against the wall, it may cause stains on the wall.

Do not take in the outlet air discharged by other units directly.
2 When front and sides of unit are clear, 20 inches (500 mm) or more.
3 When any 2 sides of left, right and rear of unit are clear, 20 inches (500 mm) or more.

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

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 inch x 13/16 inch · 7/16 inch x 1 inch (11 mm × 20 mm 11 mm × 26 mm) oval hole (17-3/4 inches [450 mm] pitch).
• If the recessed bolt is too long, change it for a shorter one (field-supplied).
  

Drilling

1. Determine where the holes will be located on the wall.
2. Drill a ø 3 inches (75 mm) hole. The outdoor side should be 6/32 to 9/32 inch (5 to 7 mm) lower than the indoor side.
3. Insert wall hole sleeve (C).
   
   

Connecting Wires for the 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.

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

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

3. Remove corner box R and electrical cover.

4. Remove display panel, conduit cover and conduit plate.

5. 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 inch (10 mm). (Fig. 1) Elbow joint should appear less than 1-3/16 inches (30 mm) outside. (Fig. 2).

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

7. 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.
   Make ground wire a little longer than others. (More than 1-9/16 inches [40 mm])

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

9. Reinstall conduit plate, conduit cover and display panel.

10. 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

• 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

• Do not cut the drain hose of the unit. (Fig. 1).

• 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. 2)

• If the drain hose provided with the indoor unit is too short, connect it with a field supplied drain hose (I). (Fig. 3)

• When connecting the drain hose to a hard vinyl chloride pipe, be sure to insert it securely into the pipe. (Fig. 4)

• Make sure that no stress is applied to the connecting portion of the drain hose after installing the indoor unit. Otherwise, breakage or water leakage may result.

• Be sure to use the drain hose attached to the indoor unit. Otherwise, water leakage or breakage due to chemical may result.

• Do not apply any agent on the drain port. Doing so may cause breakage.
  

Do not put the drain pipe directly in a drainage ditch where Ammonia or Sulphuric gas may be generated. The evaporated corrosive gas may return to the indoor side through drain pipe and this may cause an unpleasant odor and corrosion on Heat exchanger may occur.

Do not make drain piping as shown below.

Outdoor Unit Installation

Connecting Wires for the 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 supply 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 3-7/8 inches [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

(0 to 0.5)

| 0.04 to 0.06 (1.0 to 1.5)| 0.06 to 0.08 (1.5 to 2.0)| 10 to 13 (140 to 180)| 13.7 to 17.7
ø 3/8 (9.52)| 7/8 (22)| 25 to 30 (350 to 420)| 34.3 to 41.2
ø 1/2 (12.7)| 1-1/32 (26)| 0.08 to 0.10 (2.0 to 2.5)| 36 to 42

(500 to 575)

| 49.0 to 56.4
ø 5/8 (15.88)| 1-5/32 (29)| 54 to 58 (750 to 800)| 73.5 to 78.4

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 pipings to indoor unit.

• 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 by hand.
• Use tightening torque table above as a guideline for indoor unit side joints, and tighten using two wrenches. Excessive tightening damages the flare section.

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 gauges must not be used to measure vacuum. A micron gauge must be used at all times. Break 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 the 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 the valve stem of all stop valves on both sides of gas pipe and liquid pipe by the hexagonal wrench. If the valve stem hits the stopper, do not turn it any further. 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. Be sure to charge slowly with liquid refrigerant. Otherwise composition of the refrigerant in 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. Pressing the E.O. SW will perform a test run for 30 minutes. (For NAX, pressing the switch once will perform COOL operation and twice will perform HEAT operation.) If the power lamp blinks every 0.5 seconds, inspect the indoor/outdoor unit connecting wire (A). After the test run, emergency COOL mode (75ºF [24ºC] COOL) 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 (Fig. 1)

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 (Fig. 2)

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.
   

• Do not hold the A part when installing/removing or carrying the panel, or the panel might be damaged.
  

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 of indoor unit and pull it downward and forward as shown in the figure on the right.

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 the refrigeration circuit has a leak, do not execute pump down with the compressor.
When pumping down the refrigerant, stop the compressor before disconnecting the refrigerant pipes. The compressor may burst if air etc. get into it.

Connecting the Interface/Connector Cable to the Air Conditioner

• Connect the INTERFACE/CONNECTOR CABLE to the Indoor electronic control P.C. board of the air conditioner with the connecting cable.

• Cutting or extending the connecting cable of the INTERFACE/CONNECTOR CABLE results in defects in connecting.
  Do not bundle the connecting cable together with power supply cord, indoor/outdoor connecting wire, and/or earth wire. Keep as much distance as possible between the connecting cable and those wires.

• The thin part of the connecting cable should be stored and placed where customers cannot touch it.
  Connecting
  
  

Warning

Fix the connecting cable at the prescribed position securely. Incorrect installation may cause electric shock, fire, and/or malfunction.

MITSUBISHI ELECTRIC TRANE HVAC US LLC
HEAD OFFICE: 1340 SATELLITE BOULEVARD, SUWANEE, GA 30024, USA.

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