Trane 15 Series Assembly instructions

88-M4MHW15-1D-EN
ALL phases of this installation must comply with NATIONAL, STATE AND LOCAL CODES.
IMPORTANT — This Document is customer property and is to remain with this unit. Please return to service informa-
tion pack upon completion of work.
15 Series System (R-410A)
Mini-Split, Inverter System
Single Zone
These instructions do not cover all variations in systems or provide for every possible contingency to be met in
connection with the installation. Should further information be desired or should particular problems arise which are
not covered sufficiently for the purchaser’s purposes, the matter should be referred to your installing dealer or local
distributor.
Installer’s Guide
Single Split Indoor Unit Outdoor Unit
Heat Pump M4MHW15-A M4THS15-A
Cooling Only M4MCW15-A M4TCS15-A
© 2019 Trane All Rights Reserved

WARNING
This equipment is to be serviced by professionally trained personnel
ONLY. Under NO circumstances should an unqualified person service
it. This equipment contains refrigerant under PRESSURE and operates
at HIGH VOLTAGE. Improperly installed, adjusted or altered equipment
by an unqualified person poses safety hazards including FIRE,
ELECTROCUTION, or EXPLOSION, which could result in death or serious
injury.
Warnings and Cautions
Warnings are provided to alert others of the potential hazards that could result
in severe personal injury or death, while cautions are designed to alert others
of the conditions that could result in minor or moderate injury.
Your personal safety and the proper operation of this machine depend upon
the strict observance of these precautions.
Attention: Warnings and Cautions appear at appropriate sections
throughout this literature. Read these carefully.
WARNING: Indicates a potentially hazardous situation which, if not
avoided, could result in death or serious injury.
CAUTION: Indicates a potentially hazardous situation which, if not
avoided, could result in minor or moderate injury. It may also be used to
alert against unsafe practices.
NOTICE:Indicates a situation that could result in equipment or property
damage.
WARNING
Electrocution and Fire Hazards with Improperly Installed and Grounded
Field Wiring!
Improperly installed and grounded field wiring poses FIRE and
ELECTROCUTION hazards. To avoid these hazards, you MUST follow
requirements for field wiring installation and grounding as described in
the National Electrical Codes (NEC) and your State and/or local electrical
codes. All field wiring MUST be performed by qualified personnel.
Failure to follow these requirements could result in death or serious
injury.
2 88-M4MHW15-1D-EN
Installer's Guide

Warnings and Cautions
WARNING
R410-A Refrigerant under Higher Pressure than R-22!
The units described in this manual use R410-A refrigerant which operates at 50 to 70%
higher pressures than R-22. Use only R-410A approved service equipment. Refrigerant
cylinders are painted with "pink" color to indicate the type of refrigerant and may contain a
"dip" tube to allow for charging of liquid refrigerant into the system. For specific handling
concerns with R-410A, please contact your local sales office.
Failure to use R-410A approved service equipment could result in standard equipment
exploding under R-410A higher pressure which could result in death or serious injury.
NOTICE
Use appropriate oil with R410A systems. Oil type is found at the bottom of Connection Pipe
Requirements table (included in the outdoor unit installation manual). R-410A systems
utilize POE (Polyolester) or PVE(Polyvinyl Ether) oil. Both oil types absorb moisture readily,
yet, lubrication properties vary. Do not leave the sealed system open to atmosphere except
during service for a short period of time. If the sealed system is left open longer than four
hours, the compressor oil must be changed. These systems utilize strainers placed before
and after the expansion device in the outdoor unit, if debris or moisture is suspected, these
strainers must be changed. Do not break a vacuum with air. Do not leak check the sealed
system with compressed air. Unless instructed by factory service representative, external
refrigeration driers are prohibited.
USE ONLY THE FACTORY RECOMMENDED OIL TYPE!
Important!
Environmental Concerns
Scientific research has shown that certain man-made chemicals can affect the earth's naturally occurring stratospheric
ozone layer when released to the atmosphere. In particular, several of the identified chemicals that may affect the
ozone layer are refrigerants that contain chlorofluorocarbons (CFC's) and those containing hydro-chlorofluorocarbons
(HCFC's). Not all refrigerants containing these compounds have the same potential impact to the environment. The
Company advocates the responsible handling of all refrigerants, including industry replacements for CFC's such as
HCFC's and HFC's.
Responsible Refrigerant Practices
The manufacturer believes that responsible refrigerant practices are important to the environment, our customers,
and the air conditioning industry. All technicians who handle refrigerants must be certified. The Federal Clean Air Act
(Section 608) sets forth the requirements for handling, reclaiming, recovering and recycling of certain refrigerants and
the equipment that is used in these service procedures. In addition, some states or municipalities may have additional
requirements that must also be adhered to for responsible management of refrigerants. Know the applicable laws and
follow them.
88-M4MHW15-1D-EN 3
Installer's Guide

Table of Contents
Safety Precautions .................................................................................................................... 5
Pre-Installation Checklist ........................................................................................................... 6
Items Shipped With the System ................................................................................................ 7
Necessary Tools ........................................................................................................................ 7
Typical Installation Setup........................................................................................................... 8
Names and Functions of Each Part........................................................................................... 8
Clearance Requirements........................................................................................................... 9
Connection Pipe Requirements............................................................................................... 10
Refrigerant Piping Precautions................................................................................................ 11
Nitrogen Purging While Brazing............................................................................................... 11
Installation Location................................................................................................................. 12
Installing the Indoor Unit.......................................................................................................... 13
Mounting Location ................................................................................................................... 13
Drilling the Piping Hole ............................................................................................................ 14
Refrigerant Piping at the Indoor Unit ....................................................................................... 15
Installing the Condensate Pipe................................................................................................ 17
Wiring at the Indoor Unit.......................................................................................................... 17
Binding the Pipes and Cables ................................................................................................. 19
Hanging the Indoor Unit........................................................................................................... 19
Installing the Outdoor Unit....................................................................................................... 20
Condensate Management of the Outdoor Unit........................................................................ 20
Installing the Refrigerant Piping............................................................................................... 21
Flaring Process and Bending Pipes ........................................................................................ 21
Refrigerant Piping at the Outdoor Unit .................................................................................... 22
Insulating the Refrigerant Piping and Connections ................................................................. 22
Piping Requirements ............................................................................................................... 23
Vacuum and Refrigerant Leakage Detection........................................................................... 24
Wiring Precautions .................................................................................................................. 25
Outdoor Wiring Connections ................................................................................................... 25
Stranded Wiring Connections.................................................................................................. 26
Electrical Connections............................................................................................................. 27
Power Supply Wiring................................................................................................................ 28
Cable Specifications and Grounding Requirements................................................................ 28
Installation of Controllers......................................................................................................... 28
Post Installation Checklist........................................................................................................ 29
Test Operation ......................................................................................................................... 29
Refrigerant System Diagrams ................................................................................................. 30
Wiring Diagrams ...................................................................................................................... 31
Unit Dimensions ...................................................................................................................... 34
Common Error Codes............................................................................................................. 37
Troubleshooting ....................................................................................................................... 38
Auxillary Operation .................................................................................................................. 39
Indoor Unit Maintenance ......................................................................................................... 39
General Maintenance .............................................................................................................. 40
4 88-M4MHW15-1D-EN
Installer's Guide

WARNING This mark indicates a potentially hazardous situation which, if not avoided,
could result in death or serious injury.
CAUTION
This mark indicates a potentially hazardous situation which, if not avoided,
could result in minor or moderate injury. It may also be used to alert against
unsafe practices.
NOTICE This mark indicates a situation which could result in equipment and/or property
damage.
Safety Precautions
Your personal safety and the proper operation of this equipment depend upon the strict observance of
these precautions.
WARNING
1. Installation should performed by a qualified HVAC professional. Industry Standard Personal Protective
Equipment (PPE) and gear for height related safety should be worn during installation. Improper
personal safety precautions and installation may cause death or serious injury.
2. Install the air conditioner according to the instructions given in this manual. Incomplete installation
work may cause water leakage, electrical shock or fire.
3. Use the supplied or specified installation parts. Use of other parts may cause the unit to come loose,
resulting in water leakage, electrical shock or fire.
4. Install the unit in a location that can support the weight of the unit. An inadequate support structure
or incomplete installation may cause injury or property damage in the event the unit falls off of the
installation location. Refer to the installation specifications for additional requirements.
5. Electrical work should be carried out in accordance with the installation manual and local, state and
National Electric Code (NEC). Insufficient capacity or incomplete electrical work may cause electrical
shock or fire.
6. Use a dedicated power circuit. Never use a power supply shared by another appliance.
7. For wiring, use a cable that is long enough to cover the entire distance without splicing. Do not use an
extension cord. Do not put other loads on the power supply; use a dedicated power circuit. Failure to
do so may cause abnormal heat, electric shock or fire.
8. Use the specified types of wires for electrical connections between the indoor and outdoor units.
Firmly clamp the interconnecting wires so their terminals receive no external stresses. Incomplete
connections or clamping may cause terminal overheating or fire.
9. After joining the interconnecting and supply wiring, shape the cables so that they do not put undue
force on the electrical covers or panels. Install covers over the wires. Incomplete cover installation may
cause terminal overheating, electrical shock, or fire.
10. If any refrigerant leaks out during the installation, ventilate the room. The refrigerant produces a toxic
gas if exposed to flames.
11. When installing or relocating the system, keep the refrigerant circuit free from substances other than
the specified refrigerant (R410-A), such as air. The presence of air or other foreign substances in the
refrigerant circuit can cause an abnormal pressure rise or rupture, which could result in injury and
damage.
88-M4MHW15-1D-EN 5
Installer's Guide

Pre-Installation Checklist
1. Unpack and inspect each unit.
2. Check for any damage to the unit.
3. Check the model numbers to ensure a proper match.
4. Check the unit nameplate to ensure the proper electrical requirements will be met.
5. Check the installation locations to ensure the weight of the units can be supported.
6. Check the refrigerant pipe sizes and ensure they have been or will be installed according to the requirements in
this manual.
7. Check the outdoor unit nameplate for electrical power supply and wiring requirements to ensure the proper wiring
has been installed prior to connection.
8. Check the indoor unit for coil leakage. The pressure relief valve on the gas pipe should release pressurized
nitrogen which ensures the unit has not leaked during shipping.
CAUTION
1. Do not install the unit in a place where there is danger of exposure to flammable gas leakage. If gas
leaks and builds up around the unit, it may result in fire.
2. After system installation is completed, make sure no refrigerant leakage is present.
3. This appliance is not intended for use by persons with a lack of experience and knowledge, unless
they have been given adequate supervision or instruction concerning use of the appliance by a
person responsible for their safety.
4. Children should be supervised to ensure that they do not play with the appliance.
NOTICE
1. Establish drain piping according to the instructions in this manual. Inadequate piping may cause
flooding.
2. Tighten the flare nut according to the specified method. If the flare nut is tightened too hard, the flare
nut may crack and cause refrigerant leakage.
12. If a system pump-down is performed, turn off the associated equipment and close service valves prior
to removing the refrigerant piping. Failure to do so will introduce non-condensables in the system,
causing abnormal pressure in the refrigeration cycle which could lead to injury and damage.
13. Before system start-up, attach the refrigerant piping securely. Failure to do so will introduce non-
condensables into the system when the compressor is running, causing abnormal pressure in the
refrigeration cycle which could lead to injury and damage.
14. Establish a complete ground. Do not ground the unit to a utility pipe, arrester, or telephone ground.
An incomplete ground may cause electrical shock, or fire. A high surge current from lightning or other
sources may cause damage to the air conditioner.
15. If the power supply cable is damaged, it must be replaced by the manufacturer, its service agent or
another qualified professional in order to avoid electrical risk during and after replacement.
6 88-M4MHW15-1D-EN
Installer's Guide

Items Shipped with the 15 Series Mini-Split System
After unpacking the unit(s), please refrain from disposing of the packaging materials until items listed below
are located. If any of these are missing, please contact the point of sale to obtain these items.
Indoor Unit
1. Wireless handheld remote control
2. Refrigeration pipe insulation (short piece)
3. Mounting Plate
4. Installation instructions (may be included in outdoor unit)
5. Batteries for the remote control*
6. Flare nuts for connecting refrigerant pipes*
7. Mounting fasteners*
Outdoor Unit
1. Installation Manual
2. Warranty Letter
3. Drain pipe connector
*typically packaged in cellophane bubble
Necessary tools
1. Drill
2. Hole Saw
3. Phillips(TM) screwdriver
5. Vacuum pump capable of pulling to 350 microns
6. Manifold gauge set designed for this type of equipment
7. Manifold gauge hoses with 5/16" connections or 1/4" to 5/16" adapters.
8. Tubing benders
9. R-410A Flaring tool
10. Adjustable wrench
11. Nitrogen regulator
12. Nitrogen flow meter
13. Tube cutter
88-M4MHW15-1D-EN 7
Installer's Guide

(Sold Separately)
* Field provided
1
(8)
(1)
(2)
(3) (4)
(5)
(6)
(7)
(10)
(9)
1 - Front Panel
2 - Filter
3 - Guide Louver
4 - Wall Pipe*
5 - Bind Tape*
6 - Connection Wire*
7 - Drainage Pipe*
8 - Power Cable*
9 - Wired Controller
(Sold Separately)
10 - Remote Controller
Indoor Unit
Outdoor Unit
Typical Installation Setup
8 88-M4MHW15-1D-EN
Installer's Guide

valve cover
Space to the wall
Space to the ceiling
Space to the wall
Space to the wall
Air outlet side
Space to the floor
or more
or more
6 in. or more 6 in. or more
12 in. or more
20 in. or more
20 in. or more
12 in. or more
or more
.n
i
97
or more
Space to the obstruction
Air outlet side
Space to the wall
Air inlet side
The dimensions of the space necessary for correct
installation of the appliance including the minimum
permissible distances to adjacent structures
6 in.
66
in.
118 in.
Clearance Requirements
NOTE:
The maximum recommended height from the floor to the bottom of the indoor unit is 11.5 ft. (3.5 m).
88-M4MHW15-1D-EN 9
Installer's Guide

Operating Ranges
Connection Pipe Requirements
Cooling Operating Range Outdoor Temperature 0 - 115°F (-18 - 46.1°C)
Heating Operating Range Outdoor Temperature -4 - 75°F (-20 - 24°C)
Indoor Operating Range Indoor Temperature 61 - 86°F (16 - 30°C)
NOTICE
The maximum length of the connection pipe is listed in the table below. Do not place the units
such that the distance between them exceeds the maximum length of the connection pipe.
NOTES:
1. The connection pipe should be insulated with proper water-proof insulating material
2. Wall thickness of pipe 0.5-1.0 mm (0.02-0.04 in): bearing pressure 435 PSI (3.0 MPa)
3. Shorter connecting pipe lengths result in greater thermal efficiency, so it is preferable to reduce
connecting pipe lengths where possible.
4. See the oil trap instructions on page 21 for specific requirements when there is height
difference between the indoor and outdoor unit greater than 20 feet.
Heat Pump M4THS1509A M4THS1512A M4THS1518A M4THS1524A
M4MHW1509A M4MHW1512A M4MHW1518A M4MHW1524A
Refrigerant Charge (oz.) 24.7 30 49.4 65.3
Standard Length m (ft) 7.6 (25)
Additional Refrigerant Charge (oz/ft)
For Piping Beyond Standard Length 0.2 0.5
Outer Diameter Liquid Pipe mm (in) Φ6.35 (1/4")
Gas Pipe mm (in) Φ 9.52 (3/8") Φ12.7 (1/2") 15.875 (5/8")
Max Distance Height m (ft) 20 (65)
Length m (ft) 30 (100) 40 (130)
Minimum Piping Length m (ft) 3 (10)
Compressor Oil Used DAPHNE FVC50K (PVE Oil) RB68EP (POE Oil)
Cooling Only M4TCS1509A M4TCS1512A M4TCS1518A M4TCS1524A
M4MCW1509A M4MCW1512A M4MCW1518A M4MCW1524A
Refrigerant Charge (oz.) 24.7 30 35.3 56.4
Standard Length m (ft) 7.6 (25)
Additional Refrigerant Charge (oz/ft)
For Piping Beyond Standard Length 0.2
Outer Diameter Liquid Pipe mm (in) Φ6.35 (1/4")
Gas Pipe mm (in) Φ 9.52 (3/8") Φ12.7 (1/2") 15.875 (5/8")
Max Distance Height m (ft) 20 (65)
Length m (ft) 30 (100) 40 (130)
Minimum Piping Length m (ft) 3 (10)
Compressor Oil Used DAPHNE FVC50K (PVE Oil) RB68EP (POE Oil)
10 88-M4MHW15-1D-EN
Installer's Guide

Refrigerant Piping Precautions
Nitrogen Purging While Brazing
WARNING
Hazard of Explosion and Deadly Gases!
Failure to follow all proper safe refrigerant handling practices could result in death or serious
injury. Never solder, braze or weld on refrigerant pipes or any unit components that are above
atmospheric pressure or where refrigerant may be present. Always remove refrigerant by
following the guidelines established by the EPA Federal Clean Air Act or other state or local
codes as appropriate. After refrigerant removal, use dry nitrogen to bring system back to
atmospheric pressure before opening system for repairs. Mixtures of refrigerants and air under
pressure may become combustible in the presence of an ignition source leading to an explosion.
Excessive heat from soldering, brazing or welding with refrigerant vapors present can form
highly toxic gases and extremely corrosive acids.
NOTICE
System Component Damage!
Do not remove the seal caps from the refrigerant connections and piping until prepared to braze
refrigerant pipes to the connections. Excessive exposure to atmosphere (greater than 5 minutes)
may allow moisture or other particulates to contaminate the system, damaging valve seals and
causing ice formation in the system components during operation.
Nitrogen purging while brazing refrigerant pipes
Flow meter
Pressure regulator
Stop valve
Nitrogen
Nitrogen
NOTICE
Avoid Unit Damage!
Never braze pipe connections without performing nitrogen purging. Failure to perform this
procedure will damage the unit, resulting in capacity loss and reduced long-term reliability.
While brazing refrigerant pipes, continuously purge them with nitrogen gas. Use a pressure
regulator to maintain a flow rate of 1.76 ft³/h (0.05 m³/h) or more.
88-M4MHW15-1D-EN 11
Installer's Guide

WARNING
Adequate Support Required!
The wall structure must be adequate to support the weight of the unit. Failure to ensure
adequate structural support could result in death, serious injury, and equipment or
property damage.
Installation Location
Indoor Unit
1. Avoid locating the indoor unit where the return and/or supply air may be obstructed.
2. Select a location where equipment condensate can be appropriately drained.
3. Keep the indoor unit away from heat sources, vapor, and flammable gas.
4. Select a location that meets or exceeds the clearance specifications in this manual.
5. Allow space for routine maintenance, such as changing filters or servicing the equipment.
6. Install in a location sufficiently away from other electronic appliances that could cause
interference, such as television, audio devices, etc.
Outdoor Unit
1. Select a location where equipment noise and air discharge annoyance is minimized.
2. Select a location where there is sufficient ventilation.
3. Make sure the air inlet and outlet are not blocked by any obstacles
4. Select a location capable of supporting four times the weight of the unit, that will not increase
vibration, and where installation work can be carried out safely.
5. Select a location away from flammable gas or gas leaks.
6. Ensure installation of the outdoor unit conforms to the clearance specifications in this manual.
7. Locate the outdoor unit away from any bedroom windows.
NOTICE
Installing the unit in one of the following locations could result in unit malfunction:
1. Places where oil (machine oil) is used.
2. Seaside places with high levels of salt in the air.
3. Places with high levels of sulphur gas such as areas with hot springs.
4. Places where high-frequency waves are generated by radio equipment, welders and medical
equipment.
5. Other unusual places where unit operation may be altered.
6. Places where minimum clearances cannot be met.
WARNING
1. Install the unit on a level surface or on supports that are level.
2. If the location is subject to strong winds, the additional force must be accounted for
and the unit must be fixed securely to the base. Refer to local codes for additional
requirements.
Selecting the Installation Location
12 88-M4MHW15-1D-EN
Installer's Guide

Installing the Indoor Unit
WARNING
Hazardous Service Procedures!
The maintenance and troubleshooting procedures recommended in this section of the
manual could result in exposure to electrical, mechanical or other potential safety
hazards. Always refer to the safety warnings provided throughout this manual
concerning these procedures. Disconnect all electrical power including remote disconnect and
discharge all energy storing devices such as capacitors before
servicing. Follow proper lockout/tag out procedures to ensure the power can not be
inadvertently energized. When necessary to work with live electrical components, have
a qualified licensed electrician or other individual who has been trained in handling live
electrical components perform these tasks. Failure to follow all of the recommended
safety warnings provided, could result in death or serious injury.
Mounting Location
1. Confirm the mounting location with the customer. Keep in mind the guidelines for a safe
installation location on page 8-9.
2. Place the wall-mounting frame on the wall and check that it is level. Mark the screw holes to be
drilled, ensuring they are in a place with adequate support.
a. It is equally important to assure the mounting surface (i.e. wall) is flat. Use a straight
edge to assure the section of the mounting surface, in which the unit will be secured, is
neither concave or convex.
b. For corrugated walls, indoor unit installation is recommended on a solid backing affixed to
the wall.
3. Drill the holes on the wall according to the selected marks. If the mounting plate cannot
be directly affixed to wall studs or other solid backing, wall anchors shall be used to secure
mounting plate.
4. Attach the wall-mounting frame with the supplied tapping screws and check to make sure it is
firmly attached. If any of the screws or anchors are loose, select another point on the frame to
re-drill and attach securely.
5. Be sure that the wall-mounting frame has been secured firmly enough to withstand the weight
of the unit. The weight should be evenly distributed to the fasteners.
6. Prior to leaving the job site, seal any and all openings in the wall caused by the installation
process.
88-M4MHW15-1D-EN 13
Installer's Guide

1. When the position of the drain piping has been selected, cut out the corresponding knock-
out from the unit housing.
2. Select the position of the piping hole to be drilled according to the direction of the drain pipe
position selected for the application. The position of the piping hole should be slightly lower
than the wall mounted frame.
3. Drill a hole with the diameter of 2 3/16 inch or 2 3/4 inch (24K unit) for the selected outlet
pipe position. In order to drain smoothly, slant the piping hole on the wall slightly downward
to the outdoor side with a gradient of 5-10°. (As shown below)
4. Insert a sleeve into the hole to prevent the connection piping and wiring from being
damaged when passing through the hole.
Drilling the Piping Hole
The piping can be connected in the direction of right, rear right, left or rear left.
Left
Rear left
Right
Rear right
Cut off
the hole
Left Right
Indoor
5-10
outdoor
Φ2 1/4 (55)
Φ2 3/4 (70)
inch(mm)
Left
Wall
Φ2 1/4 inch (57mm)
Right
Mark in the middle of it Level
Rear piping hole
Wall
Space
to the
wall
min.
6 inch
Space
to the
wall
min
6 inch
Φ2 1/4 inch (57mm)
Rear piping hole
12K:09K:
Left
Wall
Φ2 1/4 inch (57mm)
Right
Mark in the middle of it Level
Rear piping hole
Wall
Space
to the
wall
min.
6 inch
Space
to the
wall
min.
6 inch
Φ2 1/4 inch (57mm)
Rear piping hole
Left
Wall
Φ2 3/4 inch (70mm)
Right
Mark in the middle of it Level
Rear piping hole
Wall
Space
to the
wall
min.
6 inch
Space
to the
wall
min.
6 inch
Φ2 3/4 inch (70mm)
Rear piping hole
24K:18K:
Left
Wall
Φ2 1/4 inch (57mm)
Right
Mark in the middle of it Level
Rear piping hole
Wall
Space
to the
wall
min.
6 inches
Space
to the
wall
min.
6 inches
Φ2 1/4 inch (57mm)
Rear piping hole
14 88-M4MHW15-1D-EN
Installer's Guide

Refrigerant Piping at the Indoor Unit
Note: Until the outdoor unit is set and ready to connect refrigeration pipes, do not remove the caps
from the indoor unit.
NOTICE
1. Connect each pipe to its port on the indoor unit correctly. If the centering is improper, the
flare nut cannot be tightened smoothly. If the flare nut is forced to turn, the threads will be
damaged. Refer to the flaring process guidelines in this manual for additional information.
2. Do not remove the tube caps nut until the connection pipe is made ready to prevent dust and
impurities from entering the system.
NOTICE
If a wall sleeve is not used, unnecessary damage to the piping and wiring could occur. This
typically results in current loss, improper grounding, and pipe leaks, Ensure no undue forces are
on the piping and wiring through wall(s) and adequate draining still occurs.
1. When connecting refrigerant pipe to the unit or removing it from the unit, please use both a
back-up wrench and the torque wrench. See illustration on page 16.
2. When connecting, place the equipment specified oil type on the backside of the copper
tube flare prior to tightening. Do not place oil on the flare face, as this will promote system
contamination, tighten it by hand and then tighten it with the spanner or adjustable wrench.
3. Refer to the torque reference table below before tightening to determine the appropriate torque
(over-tightening will damage the nut and lead to leakage).
4. Use dry Nitrogen to pressurize the piping circuit with 150 PSIG and allow it to hold while
performing other installation processes. It is recommended to apply a soap bubble solution
and observe the connection.
5. Evacuate each individual refrigeration circuit to 350 microns or below, and close off the valve
to the vacuum pump. If the pressure rises above 500 microns within one minute, but not
above 1500 microns within 5 minutes, moisture is present. If the pressure continues to rise
above 1500 microns, a leak exists in the circuit being tested.
a) If moisture is present, use triple evacuation process to eliminate the moisture.
b) If a leak is present, leak check all joints and piping.
Evacuation is not completed until the micron gauge does not rise above 500 microns within
one minute after achieving 350 micron pressure vacuum.
88-M4MHW15-1D-EN 15
Installer's Guide

Back-up Wrench
6. After evacuation is complete, additional charge can be added.
a) If no additional charge is required, break the vacuum with refrigerant, then remove the
gauge connectors.
b) slightly open the liquid valve at the OD unit, allow system to equalize, then fully open
the liquid valve and then open the vapor service valve.
7. After leak checking is complete, apply thermal insulation around the flare connections and
all exposed refrigeration pipes. Refer to the guidelines for insulating refrigerant piping and
connections in this manual for additional information.
a) Seal the insulation.
b) Inspect the insulation to assure no breakages are present.
Pipe Diameter in. (mm) Tightening Torque
1/4 (6.35) 11.25-14.75 ft-lbf / 15 ~ 20 N•m
3/8 (9.52) 22.25-29.50 ft-lbf / 30 ~ 40 N•m
1/2 (12.7) 33.25-40.50 ft-lbf / 45 ~ 55 N•m
5/8 (15.9) 44.25-47.75 ft-lbf / 60 ~ 65 N•m
16 88-M4MHW15-1D-EN
Installer's Guide

Installing the Condensate Pipe
NOTICE
Do not sharply twist or curve the condensate drain pipe. Ensure pipe ends are not submerged in
water. Drain pipe must provide adequate flow and slope downward to the outlet. Failure to do so
may result in leakage and overflow of the drain pan.
Outlet
pipe
Drain hose
Drain hose
Tape
Outlet pipe
Drain hose
Insulating pip
e
1. Connect the drain hose to the outlet pipe of the indoor unit (shown in Fig. A below).
2. Bind the joint with tape (shown in Fig. B below).
3. Wrap the pipe with insulating tape to prevent condensation (shown in Fig. C below).
Note: The drain pipe must be routed lower and sloped downward away from the indoor unit.
Fig. A Fig. B Fig. C
Wiring at the Indoor Unit
1. Open the front panel of the indoor unit, remove the screw on the wiring cover and remove the
cover (shown in Fig. D below).
2. Thread the power connection wire through the cable-cross hole at the back of the indoor unit
and pull it through to the front side (shown in Fig. E below).
wiring cover
screw
panel
power connection
wire
cable-cross
hole
Fig. D Fig. E
WARNING
Disconnect all electrical power and discharge all energy storing devices such as capacitors to
the outdoor unit(s) prior to wiring the indoor unit(s) to avoid risk of death, injury, or damage to
equipment.
88-M4MHW15-1D-EN 17
Installer's Guide

NOTE: The wiring diagrams in this guide are included as a reference. The manufacturer
has a policy of continuous product and product data improvement and reserves the
right to change design and specifications without notice. Always check the unit
nameplate and wiring diagram for the actual unit requirements.
3. Remove the wire clip and connect the power connection wire to the wiring terminal according to
the correct color coding. It is recommended to use 4 wire colors (for example: Blue, Black, Red,
Green. Connect Blue to 1, Black to 2, Red to 3 and Green to Ground). All wiring shall use ring
or spade type crimped or soldered connectors (as shown in the outdoor unit installation section
or manual). Ensure electrical connections are tight and strain reliefs are in place. Regardless
of wire color used, The wire terminals labeled 1, 2, 3 and ground must be landed on the
corresponding terminal in the outdoor unit.
4. Put the wiring cover back on the unit and tighten the fastener.
5. Close the front panel.
6. The primary disconnect for both the indoor and outdoor unit shall be wired to disconnect the
branch circuit feeding the outdoor unit. The Indoor unit obtains high voltage and communication
from the outdoor unit. If the AHJ (authority having jurisdiction) requires a branch circuit
disconnect before the indoor unit, then break all three legs between the outdoor unit and indoor
unit using a switch with current ratings suitable for use with these types of systems.
7. The system must be disconnected at the outdoor unit before performing service or
maintenance to avoid risk of electric shock or damage to equipment.
8. Terminal 2 carries communication signals and should not be cut or spliced. Do not use splices
in any wire between the indoor and outdoor unit.
a) If an external drain pump with a float switch is utilized, power the drain pump from
terminals 1 and 3; the float switch should be wired to break leg 3.
b) Do not break the wire that connects terminal N(1) from the outdoor unit to terminal N(1)
on the indoor unit or the wire that connects terminal 2 from the outdoor unit to terminal 2
on the indoor unit with a float switch.
9. The ground wire must connect directly from the outdoor unit to the indoor unit. To avoid
communication errors, do not connect the ground wire to the terminal block from any other
location.
Outdoor unit connection
09,12, 18, 24K models:
3 2 N(1)
green
red black
blue
Field Wiring
3 2 N(1)
NOTE: Field wiring colors indicated in this illustration are intended as an example and
may differ based on the electrical contractor choice of wire colors.
18 88-M4MHW15-1D-EN
Installer's Guide

Binding the Pipes and Cables
Note: The refrigeration pipes shall be insulated separately to prevent heat transfer between the
two pipes.
1. At the beginning of the indoor connections, bind the insulated refrigerant pipes, power cable,
and drain hose by evenly wrapping them with an appropriate pipe tape.
2. When the drain hose needs to be separated from the binding towards the discharge point,
separate the power cable and drain hose from this binding.
3. Wrap and secure the drain hose connection at its end.
4. Evenly wrap the separately insulated liquid and gas pipes until they are close to the outdoor
connection.
5. Near the outdoor unit connection, separately wrap these pipes.
indoor unit gas
pipe
indoor and
outdoor power cord
liquid pipe
drain hose
band
drain hose
band
connection pipe
indoor power cord
Hanging the Indoor Unit
Note: It is recommended the indoor unit be mounted on a non-porous flat surface. Doing so will
reduce unfiltered air from entering the unit as well as reduce sweating behind the unit. Ensure the
insulation sections surrounding the refrigeration and condensate pipes are sealed and without
cracks or openings.
1. Insert the bound pipes and wires into the wall sleeve and pass through to the outside.
2. Hang the indoor unit on the wall-mounting frame.
3. Seal any and all openings and gaps with sealant.
4. Secure the wall pipe bundle with saddles.
5. Ensure the indoor unit is securely and tightly installed to the wall.
6. Do not bend the drain hose excessively to prevent blockage.
sleeve
upper hook
lower hook of
wall-mounting fram
e
88-M4MHW15-1D-EN 19
Installer's Guide

When the outdoor unit is surrounded by walls or other obstructions, the installation space of the
unit should be no less than the clearances indicated below. For efficient operation, leave three of
four directions of peripheral constructions open when possible.
WARNING
1. Install the unit on a level surface or on supports that are level.
2. If the location is subject to strong winds, the additional force must be accounted for and the
unit must be fixed securely to the base. Refer to local codes for additional requirements.
＞12(305)
＞20(508)
＞79(2000) ＞12 (305)
＞12(305)
＞20(508)
＞79(2000)
inch(mm)
Installing the Outdoor Unit
Select the installation location that provides easy access to the indoor unit.
1. Make sure the location can support at least four times the weight of the unit.
2. Secure the outdoor unit on the selected base location with expansion screws.
3. The outdoor unit should be installed at least 1 1/4 inch above the ground or base in order to
install a drain pipe and connector (shown below).
At least 1 1/4 inch (31.8mm) clearance
Condensate Management of the Outdoor Unit
1. The outdoor unit(s) should be located where condensate poses no hazard or safety risk. Each
unit is supplied with a drain pipe connector.
2. Before installing the drain pipe fitting, appropriately plug all other base pan holes not used.
3. Install the drain pipe fitting into the appropriate hole located at the base of the unit and then
connect the drain pipe to it.
20 88-M4MHW15-1D-EN
Installer's Guide