Midea MEHS-09NIH2 User manual

Revision A: 1403100001, Content updated.
Model Numbers:
MEHS-09NiH2/MCHS-09NiH2 MEHS-09NIH1/ MCHS-09NiH1 MEHS-12NIH2/ MCHS-12NiH2
MEHS-12NIH1/MCHS-12NiH1 MEHS-18NIH2/ MCHS-18NiH2 MEHS-22NIH2/ MCHS-22NiH2
nEOLA MOnO SpLIt dC InVERtER
AIR COndItIOnER
SERVICE MAnUAL
Mono DC
Table of Contents
1. Precaution
2. Dimension
3. Refrigerant Cycle Diagram
4. Wiring Diagram
5. Installation Details
6. Operation Characteristics
7. Electronic Function
8. Troubleshooting
9. Disassembly Instructions
WARNING
 Installation MUST conform with local building codes or, in the absence of local codes, with the
National Electrical Code NFPA70/ANSI C1-1993 or current edition and Canadian Electrical
Code Part1 CSA C.22.1.
 The information contained in the manual is intended for use by a qualified service technician
familiar with safety procedures and equipped with the proper tools and test instruments
 Installation or repairs made by unqualified persons can result in hazards to you and others.
 Failure to carefully read and follow all instructions in this manual can result in equipment
malfunction, property damage, personal injury and/or death.
 This service is only for service engineer to use.

CONTENTS
1. Precaution .................................................................................................................................................... 1
1.1 Safety Precaution .......................................................................................................................... 1
1.2 Warning ......................................................................................................................................... 1
2. Part Names And Functions ......................................................................................................................... 4
2.1 Model Names of Indoor/Outdoor units .......................................................................................... 4
3. Dimension .................................................................................................................................................... 5
3.1 Indoor Unit ..................................................................................................................................... 5
3.2 Outdoor Unit .................................................................................................................................. 6
5. Refrigerant Cycle Diagram.......................................................................................................................... 8
6. Wiring Diagram ............................................................................................................................................ 9
6.1 Indoor Unit ..................................................................................................................................... 9
6.2 Outdoor Unit ................................................................................................................................ 11
7 Installation Details ...................................................................................................................................... 17
7.2 Connecting the cables ................................................................................................................. 17
7.3 Pipe length and the elevation ...................................................................................................... 17
7.4 Installation for the first time ......................................................................................................... 18
7.5 Adding the refrigerant after running the system for many years ................................................. 19
7.6 Re-installation while the indoor unit need to be repaired ............................................................ 19
7.7 Re-installation while the outdoor unit need to be repaired .......................................................... 20
8. Operation Characteristics ......................................................................................................................... 22
9. Electronic Function ................................................................................................................................... 23
9.1 Abbreviation ................................................................................................................................. 23
9.2 Display function ........................................................................................................................... 23
9.3 Main Protection ............................................................................................................................ 24
9.4 Operation Modes and Functions ................................................................................................. 25
10. Troubleshooting ....................................................................................................................................... 31
10.1 Indoor Unit Error Display ........................................................................................................... 32
10.2 Outdoor unit error display .......................................................................................................... 33
10.3 Diagnosis and Solution .............................................................................................................. 38

1
1. Precaution
1.1 Safety Precaution
 To prevent injury to the user or other
people and property damage, the following
instructions must be followed.
 Incorrect operation due to ignoring
instruction will cause harm or damage.
 Before service the unit, be sure to
read this service manual at first.
1.2 Warning
 Installation
 Do not use a defective or underrated
circuit breaker. Use this appliance on a
dedicated circuit.
There is risk of fire or electric shock.
 For electrical work, contact the dealer,
seller, a qualified electrician, or an
authorized service center.
Do not disassemble or repair the product,
there is risk of fire or electric shock.
 Always ground the product.
There is risk of fire or electric shock.
 Install the panel and the cover of
control box securely.
There is risk of fire of electric shock.
 Always install a dedicated circuit and
breaker.
Improper wiring or installation may cause
electric shock.
 Use the correctly rated breaker of
fuse.
There is risk of fire or electric shock.
 Do not modify or extend the power
cable.
There is risk of fire or electric shock.
 Do not install, remove, or reinstall the
unit by yourself (customer).
There is risk of fire, electric shock, explosion,
or injury.
 Be caution when unpacking and
installing the product.
Sharp edges could cause injury, be especially
careful of the case edges and the fins on the
condenser and evaporator.
 For installation, always contact the
dealer or an authorized service center.
 Do not install the product on a
defective installation stand.
 Be sure the installation area does not
deteriorate with age.
If the base collapses, the air conditioner could
fall with it, causing property damage, product
failure, and personal injury.
 Do not let the air conditioner run for a
long time when the humidity is very high
and a door or a window is left open.
 Take care to ensure that power cable
could not be pulled out or damaged during
operation.
There is risk of fire or electric shock.
 Do not place anything on the power
cable.
There is risk of fire or electric shock.
 Do not plug or unplug the power
supply plug during operation.
There is risk of fire or electric shock.
 Do not touch (operation) the product
with wet hands.
 Do not place a heater or other
appliance near the power cable.
There is risk of fire and electric shock.
 Do not allow water to run into
electrical parts.
It may cause fire, failure of the product, or
electric shock.
 Do not store or use flammable gas or
combustible near the product.
There is risk of fire or failure of product.
 Do not use the product in a tightly
closed space for a long time.
Oxygen deficiency could occur.
 When flammable gas leaks, turn off
the gas and open a window for ventilation
before turn the product on.
 If strange sounds or smoke comes
from product, turn the breaker off or
disconnect the power supply cable.

2
There is risk of electric shock or fire.
 Stop operation and close the window
in storm or hurricane. If possible, remove
the product from the window before the
hurricane arrives.
There is risk of property damage, failure of
product, or electric shock.
 Do not open the inlet grill of the
product during operation. (Do not touch the
electrostatic filter, if the unit is so equipped.)
There is risk of physical injury, electric shock,
or product failure.
 When the product is soaked, contact
an authorized service center.
There is risk of fire or electric shock.
 Be caution that water could not enter
the product.
There is risk of fire, electric shock, or product
damage.
 Ventilate the product from time to
time when operating it together with a stove
etc.
There is risk of fire or electric shock.
 Turn the main power off when
cleaning or maintaining the product.
There is risk of electric shock.
 When the product is not be used for a
long time, disconnect the power supply plug
or turn off the breaker.
There is risk of product damage or failure, or
unintended operation.
 Take care to ensure that nobody
could step on or fall onto the outdoor unit.
This could result in personal injury and
product damage.
 CAUTION
 Always check for gas (refrigerant)
leakage after installation or repair of
product.
Low refrigerant levels may cause failure of
product.
 Install the drain hose to ensure that
water is drained away properly.
A bad connection may cause water leakage.
 Keep level even when installing the
product.
It can avoid vibration of water leakage.
 Do not install the product where the
noise or hot air from the outdoor unit could
damage the neighborhoods.
It may cause a problem for your neighbors.
 Use two or more people to lift and
transport the product.
 Do not install the product where it will
be exposed to sea wind (salt spray) directly.
It may cause corrosion on the product.
Corrosion, particularly on the condenser and
evaporator fins, could cause product
malfunction or inefficient operation.
 Operational
 Do not expose the skin directly to
cool air for long time. (Do not sit in the
draft).
 Do not use the product for special
purposes, such as preserving foods, works
of art etc. It is a consumer air conditioner,
not a precision refrigerant system.
There is risk of damage or loss of property.
 Do not block the inlet or outlet of air
flow.
 Use a soft cloth to clean. Do not use
harsh detergents, solvents, etc.
There is risk of fire, electric shock, or damage
to the plastic parts of the product.
 Do not touch the metal parts of the
product when removing the air filter. They
are very sharp.
 Do not step on or put anything on the
product. (outdoor units)
 Always insert the filter securely.
Clean the filter every two weeks or more
often if necessary.
A dirty filter reduces the efficiency of the air
conditioner and could cause product
malfunction or damage.
 Do not insert hands or other objects
through air inlet or outlet while the product
is operated.
 Do not drink the water drained from
the product.

3
 Use a firm stool or ladder when
cleaning or maintaining the product.
Be careful and avoid personal injury.
 Replace the all batteries in the remote
control with new ones of the same type. Do
not mix old and new batteries or different
types of batteries.
There is risk of fire or explosion.
 Do not recharge or disassemble the
batteries. Do not dispose of batteries in a
fire.
They may burn of explode.
 If the liquid from the batteries gets
onto your skin or clothes, wash it well with
clean water. Do not use the remote of the
batteries have leaked.

4
2. Part Names And Functions
2.1 Model Names of Indoor/Outdoor units
Series Capacity Indoor units Outdoor units
Inverter
9k
MEHS-09NiH2 MCHS-09NiH2
MEHS-09NIH1 MCHS-09NIH1
12k
MEHS-12NIH2 MCHS-12NiH2
MEHS-12NIH1 MCHS-12NIH1
18k MEHS-18NIH2 MCHS-18NiH2
22k MEHS-22NIH2 MCHS-22NiH2

5
3. Dimension
3.1 Indoor Unit
WD
H
Model W D H
MEHS-09NiH2 680
(26.8in)
178
(7.0in)
255
(10.0in)
MEHS-09NIH1
MEHS-12NiH2 770mm
(30.3in)
188mm
(7.4in)
255mm
(10.0in)
MEHS-12NIH1
MEHS-18NIH2 905mm
(35.6in)
198mm
(7.8in)
275mm
(10.8in)
MEHS-22NIH2 1030mm
(40.6in)
218mm
(8.6in)
315mm
(12.4in)

6
LR
H
Model R(mm) L(mm) H(mm) Dimension of installation hole(mm)
MEHS-09NiH2 92mm
(3.6in)
170
(6.7in)
45
(1.8in)
Φ65mm(2.56in)
MEHS-09NIH1
MEHS-12NIH2 95mm
(3.7in)
170mm
(6.7in)
45mm
(1.8in)
MEHS-12NIH1
MEHS-18NIH2 80mm
(3.1in)
100mm
(3.9in)
45mm
(1.8in)
Model R(mm) L(mm) H(mm) Dimension of installation hole(mm)
MEHS-22NIH2 163mm
(6.4in)
293mm
(11.5in)
45mm
(1.8in)
Φ65mm(2.56in)
3.2 Outdoor Unit
H
L R

7
More than 60cm(23.6in)
More than 70cm(27.6in)
More than 30cm(11.8in)
More than 60cm(23.6in)
(Service space)
Fence or
obstacles
More than 30cm(11.8in)
Note: The above drawing is only for reference. The appearance of your units may be different.
Model W H D W1 A B
MCHS-09NiH2 700
(27.6in)
240
(9.4in)
540
(21.3in)
757
(29.8in)
458
(18.0in)
250
(9.8in)
MCHS-09NIH1 660mm
(26.0in)
265mm
(10.4in)
540mm
(21.3in)
732mm
(28.8in)
458mm
(18.0in)
276mm
(10.9in)
MCHS-12NIH1 660mm
(26.0in)
265mm
(10.4in)
540mm
(21.3in)
732mm
(28.8in)
458mm
(18.0in)
276mm
(10.9in)
MCHS-12NiH2 780
(30.7in)
250
(9.8in)
540
(21.3in)
843
(33.2in)
549
(21.6in)
276
(10.9in)
MCHS-18NiH2 760mm
(29.9in)
285mm
(11.2in)
590mm
(23.2in)
823mm
(32.4in)
530mm
(20.9in)
290mm
(11.4in)
MCHS-22NiH2 845mm
(33.3in)
320mm
(12.6in)
700mm
(27.6in)
908mm
(35.7in)
560mm
(22.0in)
335mm
(13.2in)

8
5. Refrigerant Cycle Diagram
INDOOR OUTDOOR
LIQUID SIDE
GAS SIDE
HEAT
EXCHANGE
(EVAPORATOR)
HEAT
EXCHANGE
(CONDENSER)
COMPRESSOR
2-WAY VALVE
3-WAY VALVE
CHECK VALVE
(Heating Model only)
CAPILIARY TUBE
REVERSING VALVE
(Heating Model only)
COOLING
HEATING
ACCUMULATOR