MrCool Universal Series User manual

Universal™ Series
Air Handler
Please read this manual carefully before installation and keep it for future reference.
Copyright © 2019 MRCOOL, LLC
Thank you for choosing MRCOOL. Please read this manual carefully before installation and keep it for future reference.
Owner’s Manual

Contents
Page 1 mrcool.com
EU Disposal Guidelines .............. 28
6
Post Installation Checks ........... 21
3
Troubleshooting ......................... 23
4
Maintenance and Care ................ 27
5
Unit Installation ........................... 9
1. Pre-Installation Instructions............................ 9
3. Conventional Line Set Installation................ 11
3. No-Vac® Quick Connect ® Installation....... 12
4. Condensate Removal ..................................... 13
2. Installation Location ....................................... 10
6. Electric Heater .................................................. 15
7. Electrical Connection ...................................... 16
5. Ductwork ............................................................ 14
2
1. Introduction ........................................................ 5
2. Accessories ........................................................ 6
4. Main Parts ........................................................... 8
1Appliance Overview ..................... 5
Safety Precautions ....................... 2
!
3. Unit Dimensions ................................................ 7

Page 2
Safety Precautions
mrcool.com
WARNING
Please read the manual in its entirety before installing, operating or repairing.
DO NOT share the electrical circuit with other appliances. Improper or insufficient power supply
can cause fire or electrical shock.
When connecting refrigerant piping, DO NOT let substances or gases other than the refrigerant
enter the unit. The presence of other gases or substances will lower the unit’s capacity, and may
cause abnormally high pressure in the operation cycle. This may cause explosion and injury.
DO NOT connect the ground wire to a gas pipe, water pipe, lightning arrester or telephone wire.
DO NOT allow children to play with the air conditioner. Children should be supervised around the
unit at all times.
DO NOT alter the settings of the pressure sensor or other protective devices; if short-circuited or
modified, fire or even an explosion could occur.
Installation must be performed by an authorized technician. Improper installation may cause
water leakage, electrical shock, or fire.
Installation must be performed according to installation instructions. Improper installation may
cause water leakage, electrical shock, or fire.
In North America, installation must be performed in accordance with the requirement of NEC and
CEC (by authorized personnel only.) Contact an authorized service technician for repair or
maintenance of the unit.
Only use the included accessories and specified parts for installation. Using non-standard parts
can cause water leakage, elctrical shock, or fire and may cause the unit to fail.
Read Before Installation
Incorrect installation may cause serious damage or injury.
The seriousness of potential damage or injuries is classified as either a WARNING or CAUTION.
WARNING
CAUTION
This symbol indicates ignoring instructions may cause death or serious injury.
This symbol indicates that ignoring instructions may cause moderate injury
to your person, damage to your unit, or other property.
This symbol indicates that you should NEVER perform the indicated action.
1.
2.
3.
4.
!
Safety Precautions

Page 3
Safety Precautions
mrcool.com
Note about Flourinated Gasses:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
6.
5.
Install the unit in a firm location that can support the unit’s weight. If the installation location
cannot support the weight, or the installation is performed improperly, the unit may fall and
cause serious injury and/or damage.
For all electrical work, follow all appropriate wiring standards, regulations, and the Installation
Manual.
You must use an independent circuit to supply power. Do not connect other appliances to the
same circuit. Insufficient electrical capacity or defects in electrical work can cause electrical
shock or fire.
For all electrical work, fuse the specified cables. Connect cables tightly and clamp them securely
to prevent external forces from damaging the terminal. Improper electrical connections may
overheat, causing fire and/or electrical shock.
All wiring must be properly arranged to ensure that the control board cover can close properly.
If the control board cover is not closed properly, it can lead to corrosion and cause the
connection points on the terminal to overheat , causing fire and/or electrical shock.
In certain functional environments, such as kitchens, server rooms, etc., the use of specially
designed air-conditioning units is highly recommended. If the supply cord is damaged, it must
be replaced by the manufacturer, its service agent, or similarly qualified persons in order to
avoid a hazard.
This appliance can be used by children aged 8 years and older and persons with reduced
physical, sensory, or mental capabilities or lack of experience and knowledge if they have been
given supervision or instruction concerning use of the appliance in a safe way and understand
the hazards involved. Children should not play with the appliance. Cleaning and user
maintenance should not be made by children without supervision.
The air conditioner unit can only be cleaned after it has been turned off and disconnected from
power, otherwise electric shock may occur.
If installed in a compact space, ensure that there is adequate ventilation in case of leakage.
Concentration of refrigerant gas can lead to explosion and other hazards.
The fixed wires connecting to this appliance must be configured with an all-pole disconnect
under voltage class III.
This air-conditioning unit contains R410A flourinated gases.
The refigerant gas may not have an odor, thus this should not be considered a means of leak
detection.
Installation, service, maintenance, and repair of this unit must be performed by a certified techni-
cian.
Product uninstallation and recycling must be performed by a certified technician.
If the system has a leak-detection system installed, it should be checked for leaks at least every 12
months.
Keep a record of all leak checks for the lifetime of the unit.

Page 4
Safety Precautions
mrcool.com
1.
2.
For units that have an auxiliary electric heater, DO NOT install the unit within 3 feet (1 meter) of
combustible materials.
DO NOT install the unit in a location that may be exposed to combustible gases. If combustible
gas accumulates around the unit, it may cause fire.
DO NOT operate your air conditioner in a wet room such as a bathroom or laundry room. Too
much exposure to water may cause electrical components to short circuit.
DO NOT put appendages or other objects into the air inlet or return grills.
DO NOT stop the appliance by directly cutting off the power. Turn off the unit first.
DO NOT install the appliance in areas with:
• oil, smoke, or volatile liquid, as plastic parts may deteriorate, adversely affecting the integrity
and functionality of the appliance.
• corrosive gas; as this may corrode copper piping and welds, adversely affecting the integrity
and functionality of the appliance.
DO NOT force-dry the filter using open flame or blowers, as this could damage it.
This appliance must be properly grounded during installation, or electrical shock may occur.
Install drainage piping according to the instructions in this manual. Improper drainage may
cause water damage to your home and property.
This appliance must be stored in a well ventilated area equal in size to the area specified for
operation.
Use proper measures to protect the unit from rodents and other small animals that may
damage electrical components, causing the unit to malfunction.
If wired control (i.e. a wall-mount thermostat) is to be used, it should be connected first before
powering up the unit, otherwise it may not funciton properly.
Only use a soft dry cloth or, as necessary, a slightly wet cloth with neutral detergent to clean
the casing of this appliance.
Before operating the unit under low temperature, connect it to power for 8 hours. If it is
deactivated for a short time, for example, one night, do not cut off the power (this is to protect
the compressor).
1.
2.
3.
4.
5.
6.
7.

Page 5
Safety Precautions
mrcool.com
To Our Customers;
Thank you for choosing a MRCOOL home HVAC product. Please read this manual carefully before installation
and operation of the Universal™ Series Air Handler to ensure correct use and handling. In addition to the
safety precautions in the previous section, please adhere to the following guidelines and note our exceptions
to liability.
1. This appliance can be used by children aged 8 years and older and persons with reduced physical, sensory
or mental capabilities or lack of experience and knowledge if they have been given supervision or instruction
concerning use of the appliance in a safe way and understand the hazards involved. Children should not play
with the appliance. Cleaning and user maintenance should not be made by children without supervision.
2. To ensure product reliability, the unit may consume power under stand-by status to maintain normal
communication, and for preheating refrigerant and lubricant. If the unit will not be used for an extended
period, disconnect the power supply. Reconnect the power supply and preheat the unit prior to use.
3. Ensure you have selected the proper model for the operating environment. Improper selection may impact
operating performance.
4. This product has undergone strict inspection and operational testing before leaving the factory. To avoid
damage due to improper disassembly, which may impact the normal operation, please do not disassemble the
unit without proper training and equipment.
5. For technical assistance, please contact MRCOOL technical support at [phone].
6. If the product is malfunctioning and/or is inoperable, please contact MRCOOL technical support at the fore
mentioned number, as soon as possible and provide the following information:
a. Product Nameplate Contents (model number, cooling / heating capacity, product serial number, factory
date)
b. Nature of Malfunction (specify the circumstances before and after the error occurred)
7. All illustrations and information in the instruction manual are for reference only. In order to improve the
product , we will continuously assess and innovate. We retain the right to make necessary revisions to the
product from time to time. We reserve the right to revise the contents of this manual without notice.
8. If the supply cord is damaged, it must be replaced by MRCOOL, a professional service agent or similarly
qualified person in order to avoid damage to the product.
9. MRCOOL, LLC assumes no responsibility for personal injury, property loss or equipment damage caused by
improper installation and commissioning, unecessary maintenance, or failure to follow relevant federal and
state regulations, industrial standards, and the requirements of this instuction manual.
10. MRCOOL, LLC will bear no responsibilities for personal injury or property damage caused by the following:
a. Improper use of the appliance
b. Altering, maintaining, or operating the product with non-approved equipment.
c. Altering, maintaining, or operating the product outside of the guidelines of this manual.
d. Defects caused by corrosive gas.
e. Defects caused by shipping damage.
f. Failure to abide by this instruction manual or government regulations.
g. Products made by other manufacturers
h. Natural disasters, improper installation environment, or force majeure.
1
Appliance Overview

Page 6mrcool.com
Appliance Overview
1
1
(this)
1
1
Owner’s Manual
Liquid Side Stub Kit
Gas Side Stub Kit
PART LOOKS LIKE... QUANTITY
Unless otherwise stated (as “OPTIONAL”) the air conditioning system includes the following accessories. Use
all of the installation parts and accessories to install the air conditioner. Improper installation may result in
water leakage, electrical shock, fire, or equipment failure.
Please read this manual carefully before installation and keep it for future reference.
Owner’s Manual
UNIVERSAL
™
Series
For more details visit www.MrCool.com
To connect the unit
with the liquid pipe
To connect the unit
with the gas pipe
The Universal Series™ Air Handler offers the perfect combination of superior product quality, operating
efficiency, operating sound levels, and value for money. The condensing unit uses the environmentally friendly
refrigerant R410A, which is chlorine-free to help prevent damage to the ozone layer.
Accessories
OPTIONAL
No-Vac
®
Quick Connect
®
Lineset
Gas / Liquid
Pipe Assembly

Page 7 mrcool.com
Appliance Overview
Fig. 1.1
Unit Dimensions
MDUI18024/MDUI18036
Unit Dimensions (Inches/MM)
Width Depth Height A B
21-1/4 in. (540mm) 21-1/4in. (540)mm 48-1/4in. (1224mm) 11-5/8in. (295mm) 20in. (508mm)
A
H
WD
B

Page 8mrcool.com
Appliance Overview
Main Parts
Electric Box
Assembly
Centrifugal Fan
Fan Motor
Secondary Drain Pan
Evaporator
Assembly
Primary Drain Pan
Model
Cooling capacity (ton)
Optional electric heater (kW)
MDUI18024 / MDUI18036
3.0
5-20
Model Motor @ 230V～, 60Hz
HP
FLA
MDUI18024 / MDUI18036 1/2 2.1
Unit:inch(mm)
Model
Filter size
MDUI18024 / MDUI18036
19-5/16×20-5/16× 5/8(490×516×15)
Fig. 1.2

Page 9 mrcool.com
Pre-Installation Instructions
1. Checking Product Received
After receiving the product, please check for any damage caused by transportation. Shipping damage is the
responsibility of the carrier. Verify the model number, specifications, and accessories are correct prior to
installation. The distributor or manufacturer will not accept claims from dealers for transportation damage or
installation of incorrectly shipped units. If an incorrect unit is supplied, it must not be installed and it is to be
returned to the supplier. The manufacturer assumes no responsibility for the installation of incorrectly delivered
units.
2. Before Installation
Carefully read all instructions for the installation prior to installing product. Make sure each step or procedure is
understood and any special considerations are taken into account before starting installation. Assemble all tools,
hardware and supplies needed to complete the installation. Some items may need to be purchased separately.
Make sure everything needed to install the product is on hand before starting.
3. Codes & Regulations
This product is designed and manufactured to comply with national codes. It is installer’s responsibilities to install
the product in accordance with such codes and/or any prevailing local codes/regulations. The manufacturer
assumes no responsibilities for equipment installed in violation of any codes or regulations.
4. Replacement Parts... (continued on following page)
2
Unit Installation
CAUTION
• Before serving or installing this equipment. The electrical power to this unit must be in the “off” position.
• More than one electrical disconnect may exist on this unit. Failure to observe this warning may result in
electrical shock that can cause personal injury or death.
• Due to high system pressure and electrical shock potential, installation and service work can be
dangerous. Only trained and qualified persons are permitted to install or service this equipment.
Observe all warnings contained in this manual and labels/tags attached to the equipment.
1. The Conventional Weld Line Set Installation
Instructions can be found on page 11
OR
View complete install video by scanning this QR code
2. No-Vac®Quick Connect®Line Set Installation
Instructions can be found on page 12
OR
View complete install video by scanning this QR code
The Universal™ Series has 2 installation methods
MRCOOL®
Preferred Method

Page 10mrcool.com
Unit Installation
Installation Location
WARNING
• This air handler is designed for indoor installation only. Do not install it outdoors.
• When installing the air handler, take consideration to minimize the length of refrigerant tubing as
much as possible.
• When installing in an area directly over a finished ceiling (such as an attic), installation of an
emergency drain pan is required directly under the unit. See local and state codes for
requirements.
• When installing this unit in an area that may become wet, elevate the unit with a sturdy,
non-porous material. In installations that may lead to physical damage (i.e. a garage), it is advised
to install a protective barrier to prevent such damage.
This air handler is designed for a complete supply and return ductwork system. DO NOT operate
this product without complete ductwork attached.
DO NOT install the air handler in a location above or below the condenser that violates the
instructions provided with the condenser. Service clearance is to take precedence. Allow a
minimum of 24” service clearance in front of the unit.
DO NOT install the air handler in enclosed areas, such as garages, utility rooms or parking areas.
Carbon monoxide producing devices (such as an automobile, space heater, gas water heater, etc.)
should not be operated in enclosed areas such as unventilated garages, utility rooms or parking
areas because of the danger of carbon monoxide (CO) poisoning resulting from exhaust
emissions. If a furnace or air handler is installed in an enclosed area such as a garage, utility
room, or parking area, and a carbon monoxide producing device is operated therein, there must
be direct ventilation to the outside. Adequate ventilation is necessary to avoid the danger of CO
poisoning which can occur if a carbon monoxide producing device continues to operate in an
enclosed area. If these warnings are not followed, Carbon monoxide emission can be
(re)circulated throughout the building from the air handler causing serious illness including
permanent brain damage or death.
Fig. 2.1
Fig. 2.2
• If air handler is installed as Fig. 2.1, the air
handler should be concealed in a specific
room or space and make sure the air
handler is not accessible to the general
public.
• If air handler is installed as Fig. 2.2, make
sure there is enough space for care and
maintenance and the height between the air
handler and ground is above 8
feet/2500mm. and the air handler is not
accessible to the general public.
4. Replacement Parts
When reporting shortages or damages, or ordering repair parts, give the complete product model and serial
numbers as stamped on the product. Replacement parts for this product are available through your contractor or
local distributor.

Page 11 mrcool.com
Unit Installation - OPTION 1: Conventional Weld / Flare Line Set
Conventional Line Set Installation
Model External diameter (inch)
Vapor pipe Liquid pipe
3/4 3/8
Specification of Connection Pipe
Piping Preparation
1. Solder Connection
All cut ends are to be round, burr free, and cleaned. Failure to
follow this practice increases the chances for refrigerant leakage.
2. Screw Connection
Brazing Stub
Cut Off
Valves
Fig. 2.3
Fig. 2.4
Fig. 2.5
Line set size matches service valve connection
DO NOT crimp service valve connector when
pipe is smaller than connector.
Copper Piping Oil Applied (to reduce
friction with the flare nut)
Oil Applied (improves
air-tight seal)
Fig. 2.7
Fig. 2.6
Torque Wrench
Spanner
Piping Union
Flare Nut
Pipe diameter (inch)
Tightening torque (N·m)
1/4
15-30
3/8
35-40
1/2
45-50
5/8
60-65
3/4
70-75
7/8
80-85
MDUI18024 / MDUI18036

Page 12
mrcool.com
Unit Installation - OPTION 2: No-Vac®Quick Connect®Line Set
INSTRUCTIONS FOR USE WITH NO-VAC™ QUICK CONNECT® LINE SET SOLD SEPARATELY
KINK RESISTANT, PRECHARGED, SIMPLE SECURE QUICK CONNECT, 100% CONNECTION GUARANTEE
www.mrcool.com v05-30-2019


:
F1 
1.
Take out matching male connectors M1 and M2.
2.
Remove 
and ensure the threads are clean and complete.
3.
Tighten the M1 connector to the 
Tighten the M2 connector to the 
4.
Repeat INDOOR UNIT LINE SET.
5.
Unroll and route the LINE SET between the INDOOR UNIT (Handler) and the
OUTDOOR UNIT (Condenser).
6.
Remove LINE SET.
that all threads are clean and complete.

Tighten the LINE SET F1 valve to the M1 Connector 
45N. Tighten the LINE SET F2 valve to the M2 Connector 45N.
8. Repeat INDOOR UNIT LINE SET.
mage
F2 
9.
At the OUTDOOR UNIT remove the at the and open the with a hex wrench to
If close the valve immediately and that steps
Otherwiseapply soapy water 
close the valve immediately and that 
10. the  valve’s and cover 
to help .
ⱡFailure to follow the instrucons provided could result in severe harm to you, this product, or other property.
The manufacturer, distributor, and seller are not responsible for any harm resulng from the failure to follow
instrucons and the failure to follow these instrucons will void any and all warranes express or implied.
NO-VAC™
QUICK CONNECT®
LINE SET
INDOOR UNITCONNECTOR M1 & M2OUTDOOR UNIT
STEP 6
NO-VAC™ QUICK CONNECT® LINE SETs 
NO-VAC™ QUICK CONNECT® LINE SETs®
NO-VAC™ QUICK CONNECT® LINE SETs 

NO-VAC™ QUICK CONNECT® LINE SETs - 

CUTOFF VALVE

Page 13 mrcool.com
Unit Installation
Condensate Removal
1. DO NOT connect the condensate drain pipe into the waste pipe or other pipelines that are likely to produce corrosive or
peculiar smells. This will prevent odors from entering indoors or corrupting the unit.
2. DO NOT connect the condensate drain pipe into the rain pipe. This will prevent rain water from pouring in and causing
property loss or personal injury.
3. The condensate drain pipe should be connected into a special drain system for the unit.
4. The drain pan has primary and secondary drain connections. Condensate removal is performed by attaching a 3/4” PVC
pipe to the evaporator coil pan and terminated in accordance with local or state Plumbing/HVAC codes. The installation
must include a “P” style trap that is located closely to the evaporator coil. DO NOT over-tighten the drain connection in
order to prevent damage to the evaporator drain pan. See the following figure for details of a typical condensate line “P”
trap.
Drain Connection
2” Minimum
3” Minimum
Flexible Tubing
(Hose or Pipe)
Positive Liquid Seal
(Required)
Unit
IMPORTANT
The cutoff valves on the air handlers must be opened AFTER connecting the lines
and BEFORE turning on the unit. Otherwise, operation can cause leakage and/or
damage to the unit.
Fig. 2.8

Page 14mrcool.com
Unit Installation
Ductwork
This air handler is designed for a complete supply and return ductwork system.
Return ductwork:
Do not dispose of the return ductwork in an area that can introduce toxic, or objectionable
fumes/odors into the ductwork. The return ductwork is to be introduced into the air handler
bottom (upflow configuration).
Return Air Filters:
Each installation must include a return air filter for the air handler or externally using a return air
filter grille.
WARNING
DO NOT operate the unit without all ductwork completed and attached.
• Inadequate ductwork that restricts airflow can result in improper performance and compressor
or heater failure.
• Ductwork is to be constructed in a manner that limits restrictions and maintains suitable air
velocity.
• Ductwork is to be sealed to the unit in a manner that will prevent leakage.
Electric Heater
The air handlers listed in this manual do not have a factory installed electric heater. An electric heat kit is
available as an accessory. The only heater kits that can be used are HNRd series. Please refer to installation
instructions provided with heater kit for the correct installation procedure.
WARNING
• The electrical characteristics of the air handler, the electric heater kit, and the supply power
should be identical.

Page 15 mrcool.com
Unit Installation
CAUTION
1. Ensure that all power supply is disconnected prior to installing the heater kit.
2. A means of strain relief and conductor protection must be provided at the supply wire entrance into
cabinet.
3. Only use copper conductors.
4. Installation must follow national electric code and other applicable codes.
5. If this appliance is installed in an enclosed area such as a garage or utility room with any carbon
monoxide producing appliance, ensure the area is properly ventilated to the outside.
1) Refer to the Table below for the appropriate HNRd
heater kit.
2) Check for any physical damage; do not install
damaged heater kit.
3) Remove the upper access panel from air handler.
4) Remove cover plate from air handler.
5) Slide the heater kit in to the slot and secure
element plate with previously removed screws.
6) Insert power leads into the circuit breaker lugs or
stripped red and black wires (for heater kit without
circuit breaker) and tighten.
7) Connect ground wire to ground lug.
8) Break out appropriate area of the plastic circuit
breaker cover on the access panel of the air
handler.
9) Replace access panel and check operation.
Cover Plate
Heater Kit
Circuit Breaker
Bolt
Fig 2.9
HNRd5-D
HNRd8-D
Circuit breaker, 5kW heat strip
Circuit breaker, 8kW heat strip
HNRd10-D Circuit breaker, 10kW heat strip
Kit #. Description
HNRd15-D Circuit breaker, 15kW heat strip
HNRd20-D Circuit breaker, 20kW heat strip
Kit #. Description

Page 16
mrcool.com
Unit Installation
WARNING Before performing electrical work, read the following regulations
1. Electrical installation must be conducted by professionals in compliance with local laws,
regulations and this installation manual. Never artificially extend the length of a power cord. The
electric circuit must be equipped with a circuit breaker and air switch. Both must have sufficient
capacity.
2. Unit operating power must be within the nominal range stated in the instruction manual. Use
a specialized power circuit for the unit. Do not draw power from another power circuit.
3. The air conditioner circuit should be at least 1.5m away from any flammable surface.
4. The external power cord and signal wire must be effectively fixed.
5. The external power cord and signal wire must NOT directly contact any hot objects. For
example: they must not come into contact with chimney pipes, warm gas pipes or other hot
objects.
6. The external power cord and signal wire must NOT be squeezed. Never pull, stretch or bend
the wires.
7. The external power cord and signal wire must NOT collide with any metal beam or edge on
the ceiling, or touch any metal burrs or sharp metal edge.
8. Connect wires in accordance to the circuit diagram labeled on the unit or electric box. Screws
must be tightened. Slipped screws must be replaced by specialized flat-head screws.
9. Please use the power cables that are packaged with the appliance. DO NOT change the power
cables arbitrarily. Do not change the length and terminals of the power cables. If you want to
change the power cables, please contact MRCOOL’s local service center.
10. Wiring terminals should be connected firmly to the terminal board. Loose connection is not
safe.
11. After the electrical installation is finished, please use wire clamps to secure the power cord,
connection wire of temperature controller and outdoor unit, and the communication cords. Make
sure the wires are not clamped too tight.
12. The wire gauge of the power cord should be sufficiently large. A damaged power cord or
other wires must be replaced by specialized wires. Wiring work must be done according to
national wiring rules and regulations.
Vacuum Lines
Electrical Connection
Electrical Regulations

Page 17 mrcool.com
Unit Installation
Outdoor Unit Model Power Supply Max. Overcurrent
Protection (A)
208/230V
60Hz 15 amps4 amps
MDUI18024/MDUI18036
Min. Circuit
Ampacity
Electrical Connection
Electrical Parameters
1. The fuse is located on the main board.
2. Install a circuit breaker at every power terminal near the units (indoor unit and temperature controller)
with at least 0.12in (3mm) contact gap. Both units must reach the plug.
3. Circuit breaker and power cord specifications listed in the above table are determined based on the
maximum power input of the units.
4. Specifications of power cords listed in the above table are applicable in a working condition where
ambient temperature is 104°F (40°C) and multi-core copper cable (e.g. YJV copper cable, with insulated
PE and PVC sheath) is protected by a conduit, and is resistant to 194°F (90°C) in maximum (see IEC
60364-5-52). If working conditions change, please adjust the specifications according to national
standards.
5. Specifications of circuit breaker are based on a working condition where the working temperature is
104°F (40°C). If working conditions change, please adjust the specifications according to national
standards.
6. Use 5pc of AWG18 power cords as the signal wire between the indoor unit and the temperature
controller. The maximum length is 98 feet (30m). Please select a proper length according to local
conditions. Communication cords must not be twisted together.
7. The gauge of signal wire should not be less than AWG18. It’s recommended to use AWG18 power cords
as the signal wire.

Page 18mrcool.com
Unit Installation
Electrical Connection
Connecting the Power Cord & Communication Wire
For solid wires (Refer to Fig. 2.10 A):
1. Use wire cutters to cut off the wire end and then peel away about 25mm of the insulation layer.
2. Use a screwdriver to unscrew the terminal screw on the terminal board.
3. Use nippers to bend the solid wire into a ring that fits the terminal screw.
4. Form a proper ring and attach to the terminal board. Use a screwdriver to tighten the terminal screw.
For braided wires (Refer to Fig. 2.10 B &Fig. 2.10):
1. Use wire cutters to cut off the wire end and then peel away about 10mm of the insulation layer.
2. Use a screwdriver to unscrew the terminal screw on the terminal board.
3. Use a round terminal fastener or clamp to secure the round terminal firmly on the peeled wire end.
4. Locate the round terminal conduit. Use a screwdriver to replace it and tighten the terminal screw (as
shown in Fig. 2.10).
A. Solid Wire
Jacket / Insulation
1” (25mm)
B. Braided Wire
Solderless
Terminal
3/8” (10mm)
Fig. 2.10

Page 19 mrcool.com
Unit Installation
Electrical Connection
Connecting the Power Cord & Communication Wire
Screw with
Special Fastener
Round
Terminal
Wire
Terminal
Board
For all terminal wiring (Refer to Fig. 2.13 on the next page):
Lead the connection wire and power cord through the insulation tube. Then secure
the wires with wire clamps (as shown in Fig. 2.12).
Fig. 2.12
Fig. 2.11
Cord Clamp
Insulation Tube
WARNING
1. Before work begins, please check to ensure the unit is powered OFF.
2. Match the terminal numbers and wire colors with the colors indicated in the indoor unit.
3. Wrong wire connection may burn the electrical components.
4. Connect the wires firmly to the wiring box. Incomplete installation may lead to a fire hazard.
5. Please use wire clamps to secure the external covers of connecting wires. (Insulators must be
clamped securely; otherwise, electric leakage may occur.)
6. Ground wire should be connected.