Indoor unit
connection
Outdoor unit
connection
Copper
pipe
Fig. 1
Good
Tilted
No good
Fig. 2
Uneven Burred
Fig. 4
Clutch type
Flaring tool
Wing nut type
Fig. 5
Flare nut
Die
Copper pipe
Smooth all around
Even length all around
Inside is shining without any scratches.
Fig. 6
Flare nut Union joint
External thread sideInternal thread side
Tighten the are nut
with a torque wrench.
Grip the nut on the
union joint with a spanner.
Burr
Copper pipe
Spare reamer
Pipe cutter
Fig. 3
Lead
wire
19/32 inch
(15 mm)
1. Before Installation
1-1. The Following Should Always Be Observed for Safety
• Be sure to read these safety precautions and instructions.
• Be sure to observe the warnings and cautions specied here.
• After reading this manual, be sure to store it with the OPERATING INSTRUCTIONS for future reference.
• Please report to your supply authority or obtain their consent before connecting this equipment to the power supply system.
JG79N458H03
Required tools for installation
Phillips 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
Gauge manifold for R410A
Vacuum pump for R410A
Charge hose for R410A
Pipe cutter with reamer
MSZ-GS18NA
MSY-GS18NA
When installing multi units, refer to the
installation manual of the multi unit for out-
door unit installation.
1-4. Installation Diagram
Accessories
Check the following parts before installation.
<Indoor unit>
(1) Installation plate 1
(2)
Attachment screws for the installa-
tion plate
4 × 25 mm
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 lter 2
Field-supplied parts
(A)
Indoor/outdoor unit connecting wire*1
1
(B) Extension pipe 1
(C) Wall hole sleeve 1
(D) Wall hole cover 1
(E) Pipe attachment strap 2 to 5
(F) Screw for (E) 4 × 20 mm 2 to 5
(G) Piping tape 1
(H) Putty 1
(I)
Drain hose
(or soft PVC hose, 15 mm inner diam-
eter or hard PVC pipe VP30)
1
(J)
Drain hose
(or soft PVC hose, 15 mm inner diam-
eter or hard PVC pipe VP16)
0 or 1
(K)
Power supply cord*1
1
Units should be installed by licensed contractor
according to local code requirements.
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.
2-1. Attaching the Installation Plate
• Find a stud in the wall to attach installation plate (1) horizontally by tightening the x-
ing screws (2) rmly.
• 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 (eld-supplied).
2. Indoor Unit Installation
Wall
Outdoor side
2-2. 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).
2-3. Connecting Wires for the Indoor Unit
Note:
When the indoor unit is powered from the outdoor unit, depending on local code, a discon-
nect 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 appear-
ing 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 aects the connecting
section of the terminal block.
8) Firmly tighten the terminal screws. After tightening, verify that the wires are tightly fas-
tened.
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.
Less than 3/8
inch
(10 mm)
Conduit plate
Conduit pipe or
elbow joint
Lock nut
6/32-9/32 inch
(5-7 mm)
Ø 3 inches
(75 mm)
Lead
wire
19/32 inch
(15 mm)
Elbow joint
(for right, left, or downward piping)
Less than 1-3/16
inches (30 mm)
Fig. 1
Fig. 2
Fig. 3
Fig. 4 Fig. 5
Do not make drain piping as shown below.
Do not raise
Accumulated
drain water
Air
Waving
Water
leakage
Water
leakage
Water
leakage
Tip of drain
hose dipped
in water
Ditch
At least
1-31/32
inches (50
mm) gap
2-4. Pipe Forming and Drain Piping
2-4-1. 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
(eld-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 rmly 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).
Remove corner box for
piping on left side of unit.
Drain cap
Drain hose
Drain cap
Drain hose
Fig. 1 Fig. 2
Fig. 3
Fig. 4
Fig. 5
Piping tape (G)
Felt tape (4)
Rear or bottom piping
1) Place the refrigerant piping and the drain hose together, then rmly apply piping tape
(G) from the end.
2) Insert the piping and the drain hose into the wall hole sleeve (C), and attach the up-
per 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 rmly apply piping tape (G) from the end.
2) Insert the piping and the drain hose into the wall hole sleeve (C), and attach the up-
per 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).
To the left
3-1. 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 aects 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.
3-2. 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 are 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 ared work with Fig. 6.
• If are is defective, cut o the section and repeat procedure.
3. Outdoor Unit Installation
Power supply cord (K)
L1
L2
4-4. Explanation to the User
• Using the OPERATING INSTRUCTIONS, explain to the user how to use the air condition-
er (the remote controller, removing the air lters, 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.
4. Purging Procedures, Leak Test, and Test Run
4-2. 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 MSZ, pressing the switch once will perform COOL op-
eration 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 o. 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 o.
• Once the compressor stops, the restart preventive device operates so the compressor
will not operate for 3 minutes to protect the air conditioner.
4-3. Auto Restart Function
This product is equipped with an auto restart function. When the power supply is cut o
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.)
5-3. 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 o 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 o. Refer to operating instructions for details.
5-2. 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 gure on the right.
Electrical specications
MODEL
INDOOR
MSZ-GS18NA
MSY-GS18NA
OUTDOOR
MUZ-GS18NA(H)
MUY-GS18NA
MUZ-GS18NAHZ
INDOOR UNIT
Power supply (V, PHASE, Hz) 208/230, 1, 60
Min. Circuit Ampacity (A) 1.0
Fan motor (F.L.A.) (A) 0.74
OUTDOOR UNIT
Power supply (V, PHASE, Hz) 208/230, 1, 60
Max. Fuse size (time delay) (A) 15 20
Min. Circuit Ampacity (A) 12 18
Fan motor (F.L.A.) (A) 0.93 0.93
Compressor
(R.L.A) (A)
MSZ 8.4 13.6
MSY 8.4 -
(L.R.A) (A)
MSZ 10.5 17.0
MSY 10.5 -
Control voltage
Indoor unit - Remote controller: (Wireless)
Indoor unit - Outdoor unit: DC12-24 V (Polar)
Pipe
Outside diameter
Minimum wall
thickness
Insulation
thickness
Insulation material
inch (mm)
For liquid 1/4 (6.35) 0.0315 (0.8) 5/16 (8)
Heat resistant foam
plastic 0.045 Spe-
cic gravity
For gas
3/8 (9.52) 0.0315 (0.8) 5/16 (8)
1/2 (12.7) 0.0315 (0.8) 5/16 (8)
Limits
Pipe length MSZ/MSY-GS18NA 100 feet (30 m) max.
Height dierence MSZ/MSY-GS18NA 50 feet (15 m) max.
No. of bends 10 max.
Pipe length
Up to 25 feet (7.5 m) No additional charge is required.
Exceeding 25 feet (7.5 m)
Additional charge is required.
(Refer to the table below.)
Refrigerant to be
added
MSZ/MSY-GS18NA 1.08 oz each 5 feet (20 g/m)
Emergency
operation switch
(E.O. SW)
Remark:
* A disconnect switch
should be required.
Check the local code.
** Use a ring tongue termi-
nal in order to connect a
ground wire to terminal.
■ Do not install the unit by yourself (user).
Improper or incomplete installation could cause re, electric shock, injury due to
the unit falling, or water leakage. Consult a qualied installer or the dealer from
whom you purchased the unit.
■ Follow the instructions detailed in the installation manual.
Incomplete installation could cause re or electric shock, injury due to the unit fall-
ing, or leakage of water.
■ When installing the unit, use appropriate protective equipment and tools for
safety.
Failure to do so could cause injury.
■ Install the unit securely in a place that can bear the weight of the unit.
If the installation location cannot bear the weight of the unit, the unit could fall
causing injury.
■ Do not alter the unit.
It may cause re, electric shock, injury or water leakage.
■ Perform electrical work according to the installation manual and be sure to use
an exclusive circuit. Do not connect other electrical appliances to the circuit.
If the capacity of the power circuit is insucient or there is incomplete electrical
work, it could result in a re or an electric shock.
■ Ground the unit correctly.
Do not connect the ground wire to a gas pipe, water pipe, lightning rod or tel-
ephone ground. Defective grounding could cause electric shock.
■ Do not damage the wires.
Damaged wires could cause re.
■ Be sure to shut o the main power when setting up the indoor P.C. board or
wiring.
Failure to do so could cause electric shock.
■ Use the specied wires to securely connect the indoor and outdoor units. At-
tach the wires rmly to avoid applying stress to the terminal block.
Improper connection could cause re.
■ Do not install the unit in a place where ammable gas may leak.
If gas leaks and accumulates around the unit, it could cause an explosion.
■ Do not use intermediate connection of the power cord or the extension cord.
Do not connect many devices to one AC outlet.
It could cause a re or an electric shock.
■ Use the parts provided or specied parts for the installation work.
The use of defective parts could cause an injury or leakage of water due to a re,
an electric shock, the unit falling, etc.
■ When plugging the power supply plug into the outlet, make sure that there is
no dust, blockage, or loose parts both in the outlet and on the plug. Verify that
the power supply plug is completely in the outlet.
If there is dust, blockage, or loose parts on the power supply plug or the outlet, it could
cause electric shock or re. If loose parts are found on the power supply plug, replace it.
■ Securely attach the electrical cover to the indoor unit and the service panel to
the outdoor unit.
If the electrical cover of the indoor unit and/or the service panel of the outdoor unit are
not attached securely, dust, water, etc. could collect in the unit and could cause a re or
an electric shock.
■ When installing, relocating, or servicing the unit, make sure that no substance
other than the specied refrigerant (R410A) enters the refrigerant circuit.
Any presence of foreign substance such as air can cause abnormal pressure rise
and may result in explosion or injury. The use of any refrigerant other than that
specied for the system will cause mechanical failure, system malfunction, or unit
breakdown. In the worst case, this could lead to a serious impediment to securing
product safety.
■ Do not discharge the refrigerant into the atmosphere. Check that the refriger-
ant gas does not leak after installation has been completed. If refrigerant leaks
during installation, ventilate the room.
If refrigerant comes in contact with a re, harmful gas could be generated.
If refrigerant gas leaks indoors, and comes into contact with the ame of a fan
heater, space heater, stove, etc., harmful gases will be generated.
■ Use appropriate tools and piping materials for installation.
The pressure of R410A is 1.6 times higher than R22. Not using the appropriate
tools and materials, or improper installation could cause the pipes to burst causing
an injury.
■ When pumping down the refrigerant, stop the compressor before disconnecting
the refrigerant pipes.
If the refrigerant pipes are disconnected while the compressor is running and the
stop valve is open, air could be drawn in and the pressure in the refrigeration cycle
could become abnormally high, causing the pipes to burst.
■ When installing the unit, securely connect the refrigerant pipes before starting
the compressor.
If the compressor is started before the refrigerant pipes are connected and the
stop valve is open, air could be drawn in and the pressure in the refrigeration cycle
could become abnormally high, causing the pipes to burst.
■ Fasten a are nut with a torque wrench as specied in this manual.
If fastened too tight, a are nut could break and cause refrigerant leakage.
■ Install the unit according to national wiring regulations.
■ When opening or closing the valve below freezing temperatures, refrigerant may
spurt out from the gap between the valve stem and the valve body, resulting in
injuries.
■ Exercise caution when using any auxiliary heat source and follow all third party
manufacturer instructions and safety guidelines for installation and usage.
Any auxiliary heat source connected to this unit via the CN24 connection must
have an independent temperature control mechanism. Failure to install and main-
tain such temperature control mechanism may void the warranty for this unit.
Mitsubishi Electric shall not bear any warranty obligation or other liability for any
damage or loss in connection with such third party auxiliary heaters.
■ Depending on the installation area, install a Ground Fault Interrupt (GFI) circuit
breaker.
If the Ground Fault Interrupt (GFI) circuit breaker is not installed, an electric shock
could occur.
■ Perform the drainage/piping work securely according to the installation manual.
If there is defect in the drainage/piping work, water could drip from the unit, and
damage household items.
■ Do not touch the air inlet or the aluminum ns of the outdoor unit.
This could cause injury.
■ Please wear protective equipment when you touch the base of the outdoor unit.
It could cause injury if you do not wear the protective equipment.
■ Do not install the outdoor unit where small animals may live.
If small animals enter the unit and damage its electrical parts, it could cause a
malfunction, smoke emission, or re. Keep the area around the unit clean.
Caution
(Could lead to serious injury when operated incorrectly.)
Warning
(Could lead to death or serious injury.)
1-3. Specications
1-3-1. Power Supply and Indoor/Outdoor Wire Con-
nection
• Power should be taken from an exclusive branched circuit.
• Wiring work should be based on applicable technical stand-
ards.
• Wiring connections should be made following the diagram.
• Securely tighten screws.
Connecting wires and the ground wire
• Use solid conductor Min. AWG14 or stranded conductor
Min. AWG14.
• Use double insulated copper wire with 600 V insulation.
• Use copper conductors only.
* Follow local electrical codes.
Power supply cable and ground wire
• Use solid or stranded conductor.
MUZ-GS18NA(H)
MUY-GS18NA
Min. AWG14
MUZ-GS18NAHZ Min. AWG12
• Use copper conductors only.
* Follow local electrical codes.
Note:
When the indoor unit is powered from the outdoor unit, depend-
ing on local code, a disconnect switch needs to be installed to a
power supply circuit.
1-2. Selecting the Installation Location
Indoor Unit
• Where airow is not blocked.
• Where cool air spreads over the entire room.
• On a rigid wall to reduce the possibility of vibration.
• Where it is not exposed to direct sunlight. Do not ex-
pose to direct sunlight also during the period following
unpacking to before use.
• Where it can be easily drained.
• At a distance 3 feet (1 m) or more away from a TV and
radio. Operation of the air conditioner may interfere
with radio or TV reception. An amplifier may be re-
quired for the aected device.
• In a place as far away as possible from fluorescent
and incandescent lights. In order to make the infrared
remote control operate the air conditioner normally.
The heat from the lights may cause deformation or the
ultraviolet may cause deterioration.
• Where the air lter can be removed and replaced easily.
•
Where it is away from the other heat or steam source.
Note:
Install the indoor unit high on the wall where air can dis-
tribute over the entire room.
Remote Controller
• Where it is convenient to operate and easily visible.
• Where children cannot easily touch it.
• Select a position about 4 feet (1.2 m) above the oor.
Check that signals from the remote controller from
that position are received by the indoor unit (‘beep’ or
‘beep beep’ receiving tone sounds). When the remote
controller holder is supplied, install it at a position from
which the indoor unit can receive signals.
Note:
In rooms where inverter type uorescent lamps are used,
the signal from the wireless remote controller may not be
received.
Outdoor Unit
• Where it is not overly exposed to strong winds.
• Where airow is good and dustless.
• Where neighbours are not annoyed by operation
sound or hot air.
• Where rigid wall or support is available to prevent the
increase of operation sound or vibration.
• Where there is no risk of combustible gas leakage.
• If installing the unit in a location high above the ground,
be sure to secure the unit legs.
• Where it is at least 10 feet (3 m) away from the antenna
of TV set or radio. Operation of the air conditioner may
interfere with radio or TV reception in areas where re-
ception is weak. An amplier may be required for the
aected device.
• Install the unit horizontally.
• Please install it in an area not aected by snowfall or
blowing snow. In areas with heavy snow, please install
a canopy, a pedestal and/or bae boards.
Note:
• It is advisable to make a piping loop near outdoor unit
so as to reduce vibration.
• For increased efficiency, install the outdoor unit in a
location where continuous direct sunlight or excessive
water can be avoided as much as possible.
Note:
When operating the air conditioner in low outside tem-
perature, be sure to follow the instructions described
below.
• Never install the outdoor unit in a place where its air
inlet/outlet side may be exposed directly to wind.
• To prevent exposure to wind, install the outdoor
unit with its air inlet side facing the wall and
a bae
board on the air outlet side.
Avoid the following places for installation where air
conditioner trouble is liable to occur.
• Where ammable gas could leak.
• Where there is an excessive amount of machine oil
in the air.
• Where oil is splashed or where the area is lled with
oily smoke (such as cooking areas and factories,
in which the properties of plastic could be changed
and damaged).
• Salty places such as the seaside.
• Where sulde gas is generated such as hot spring,
sewage, 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.
Caution:
• After test run or remote signal reception check, turn o the unit with the E.O. SW or
the remote controller before turning o the power supply. If this procedure is not per-
formed, 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 rep-
resentative to deactivate the function. Refer to the service manual for details.
Remove
corner box
for piping on
right side of
unit
Remove corner box for pip-
ing on bottom side of unit
Unit: inch
Unit: mm
Conduit plate
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.
HEAD OFFICE: TOKYO BUILDING, 2-7-3, MARUNOUCHI, CHIYODA-KU,
TOKYO 100-8310, JAPAN
Pipe diameter
inch (mm)
B
inch
(mm)
A inch (mm) Tightening torque
Clutch
type tool
for R410A
Clutch
type tool
for R22
Wing nut
type tool
for R22
ft-lb
(kgf•cm)
N•m
ø 1/4 (6.35)
21/32
(17)
0 to 0.02
(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
4-1. 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.
Stop valve for
GAS
Stop valve cap
(Torque 15 to
22 ft-lb, 19.6 to
29.4 N•m, 200
to 300 kgf▪cm)
Vacuum pump (or the vacuum
pump with the function to
prevent the back ow)
Gauge manifold valve
(for R410A)
Compound pressure gauge
(for R410A)
–14.7 psi [Gauge]
(–0.101 Mpa)
Handle
Low
Handle High
Adapter for pre-
venting the back
ow
Charge hose
(for R410A)
Close
Open
Hexagonal wrench
Precautions when using the control valve
When attaching the control valve
to the service port, valve core may
deform or loosen if excess pressure
is applied. This may cause gas leak.
Service port
Charge hose
Body
Close
Open
Control valve
A
When attaching the control valve to
the service port, make sure that the
valve core is in closed position, and
then tighten part A. Do not tighten
part A or turn the body when valve
core is in open position.
Service port cap
(Torque 10 to 13 ft
-Ib, 13.7 to 17.7 N•m,
140 to 180 kgf•cm)
Valve stem (inside)
3) Evacuate the system to 4000 microns from both service valves. System manifold gaug-
es 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 aect performance of the air conditioner.
10) Remove gauge manifolds and replace service port caps and tighten.
11) Leak test
Stop valve for LIQUID
Pressure gauge
(for R410A)
ENGLISH
SPLIT-TYPE AIR CONDITIONERS
INSTALLATION MANUAL
• 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.
Service panel
Lock nut
Conduit cover
Conduit
plate
Conduit pipe
Liquid pipe
Gas pipe
Felt tape (4)
Indoor/outdoor unit
connecting wire (A)
Piping tape (G)
• Make ground wire a little longer than
others. (More than 1-9/16 inches [40
mm])
33-1/16
13-3/4~14-5/8
19-11/16
Air inlet
6-7/8
15-3/8
13
Air outlet
2-3/8 x 13/16 slot 1-9/16
Air inlet
40
840
175 500
Air inlet
390
330
349~371
Air outlet
2-10 x 21 slot
Air inlet
3-3. Pipe Connection
• Fasten are nut with a torque wrench as specied in the table (refer to 3-2.).
• When fastened too tight, are 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, rst align the center, then tighten the rst 3 to 4 turns of are 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 are 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.
3-4. 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 eld-supplied insulation to prevent condensation.
5. Relocation and Maintenance
5-1. Removing and Installing the Panel Assembly
Removal procedure (Fig. 1)
1) Open the front panel.
2) Remove the 3 screws which x the panel assembly.
3) Close the front panel.
4) Remove the panel assembly. Be sure to remove its bottom end rst.
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.
1
2
3
2
2
4
4
Fig. 1
Fig. 2
6. Connecting the Interface/Connector Cable to the Air Conditioner
Fix the connecting cable at the prescribed position securely. Incorrect installa-
tion may cause electric shock, re, and/or malfunction.
Warning
• 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
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 eciency of
power usage may fall about 10% at the place where
short cycle is likely occur due to poor ventilation. In-
stalling the air outlet guide (optional) can improve per-
formances.
• 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.
15-3/4 inches or
more
(400 mm or more)
39-3/8 inches or
more
(1000 mm or more)
OUTDOOR UNIT
<MUZ-GS18NA(H)>
<MUY-GS18NA>
Indoor control
P.C. board holder
(1) Remove the panel and the lower right corner box.
(2) Open the indoor control P.C. board holder 90 degrees and remove it.
(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 as shown in the gure.
(5) Hook the connecting cable into the ribs as shown in the gure.
(6) Install the indoor control P.C. board holder and then stow the extra connecting cable where
indicated in the gure. Install the lower right corner box and the panel to the original position.
Connector
Interface unit
Thick part of the connecting cable
Air conditioner
Thin part of the connecting cable.
Place this part where customers cannot touch it.
Indoor control P.C.
board
CN105
Power supply
208/230 V AC,
1 phase 2 wires,
60 Hz
INDOOR UNIT
Terminal block
208/230 V AC
,
1 phase, 60 Hz
OUTDOOR UNIT
<MUZ-GS18NAHZ>
Terminal
block 1
Ground
Grounding terminal**
Grounding
terminal**
Disconnect
switch*
Grounding terminal**
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.
Warning
Terminal block 2
Terminal
block
* Do not hold the A part when installing/removing or carrying the panel, or the panel
might be damaged.
A part : lower part of air
outlet of the panel
1-3-2. Refrigerant Pipes
• To prevent condensation, insulate the two refrigerant pipes.
Caution
Be sure to use the insulation of specied thickness (table on
the right). Excessive insulation may cause incorrect instal-
lation of the indoor unit, and too little insulation may cause
condensate to form.
• Refrigerant pipe bending radius must be 4 inches (100 mm)
or more.
• The unit has ared connections on both indoor and outdoor
sides.
• Remove the valve cover from the outdoor unit, then connect
the pipe.
• Refrigerant pipes are used to connect the indoor and outdoor
units.
• Be careful not to crush or over bend the pipe in pipe bending.
• Refrigerant adjustment... If pipe length exceeds 25 feet (7.5
m), additional refrigerant (R410A) charge is required.
(The outdoor unit is charged with refrigerant for pipe length
up to 25 feet [7.5 m])
• Please carefully consider the indoor unit location when piping
lengths are less than 16 feet (5 m) as there could be intermit-
tent noises during normal operation that would be noticeable
in very quiet environments.
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.
2-4-2. 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 insu-
lation (eld-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 eld-
supplied drain hose (I). (Fig. 3)
• When connecting the drain hose to a hard vinyl chloride pipe, be sure to insert it se-
curely 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.
Downward
slope
Drain
hose
Soft hose I.D.
19/32 inch
(15 mm)
Drain hose
Hard vinyl chloride pipe
I.D. 1-3/16 inches
(30 mm)
Insert
securely
Dierent
diameter joint
27-9/16 inches
(70 cm) or more
Fig. 2 Fig. 3 Fig. 4
Fig. 1
Installation plate (1)
Center of
ø3 inches
(ø75 mm) hole
6 5/8 inches
(168 mm)
or more
5 1/4 inches
(133 mm)
or more
4 3/8 inches (111 mm) or more
5 3/16 inches (132 mm) or more for
left and left back piping (using spacer)
Ceiling
Wall Wall
Fixing
screw (2)
Insert
the
scale. *
Align the
scale with
the line. *
4 inches (100 mm)
Level
* Same for left hole.
Indoor terminal
block
Fixing screw
Conduit cover
Lock nut
Fixing screw
Conduit plate
Elbow joint
(for right, left, or downward piping)
Electrical cover
Electrical box
Conduit pipe
(for rear piping)
or
Grounding
terminal
Indoor control
P.C. board holder
• Connect wires to the appropriate terminals
• For future servicing, leave some slack in the connecting wires.
Corner box L
Remove corner box L for
piping on left side of unit.
Remove corner box L for
piping on bottom side of unit.
Corner box R
Remove corner box R for
piping on right side of unit.
Remove corner box R for
piping on bottom side of unit.
<MUZ-GS18NA(H)>
<MUY-GS18NA>
Terminal block
to conduit cover
Power supply cord (K)
Indoor/outdoor unit
connecting wire (A)
TB support
Grounding
terminal
<MUZ-GS18NAHZ>
When the piping is to be attached to a wall
comprised of tin plate or metal netting, use
chemically treated wooden piece 25/32 inch
(20 mm) or thicker between the wall and the
piping, or wrap insulation vinyl tape around
the piping.
To use existing piping, perform COOL
operation for 30 minutes and pump down
before removing the old air conditioner.
Remake are according to the dimension
for new refrigerant.
4 3/8 inches
(111 mm) or
more / 5 3/16
inches (132 mm) or
more for left and
left back piping
(using spacer)
3/8 inch (10
mm) or more
*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
14 inches (350
mm) or more
4 inches (100
mm) or more
4 inches (100
mm) or more
clear *2
clear *3
5 1/4 inches
(133 mm)
or more
6 5/8 inches
(168 mm)
or more
After the leak test, apply insulating material
tightly so that there is no gap.
5.9 to 7.5 feet (1.8 to 2.3 m)
from the oor is recommended
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.
Indoor unit
Wall hole
sleeve (C)
Cut o the
extra length.
Pipe attachment
strap (E)
Seal the wall hole
gap with putty (H).
Attach the pipe to
wall with pipe at-
tachment strap (E).
Wall hole cover (D)
Attachment
screw (F)
Terminal block
to conduit cover
Power supply cord (K)
Indoor/outdoor unit
connecting wire (A)
TB support
Grounding
terminal
Do not block the inlet of the outdoor unit with
the excess part of the pipes.
Cover the connection part with tape to pre-
vent water from leaking.
JG79N458H03_01En.indd 1JG79N458H03_01En.indd 1 2023/03/10 11:22:082023/03/10 11:22:08
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