Midea M2OG-14HFN8-Q User manual

SERVICE MANUAL
MIDEA AIRCONDITIONER
EUROPE MARKET
SUPER DC INVERTER MULTI TYPE
M2OG-14HFN8-Q
M2OC-18HFN8-Q
M2OD-18HFN8-Q
M3OF-21HFN8-Q
M3OF-27HFN8-Q
M3OE-27HFN8-Q
M4OB-36HFN8-Q
M5OD-42HFN8-Q
M4OE-28HFN8-Q
M5OE-42HFN8-Q
DC MULTI OUTDOOR UNITS

CONTENTS
1. General information of Outdoor Units .................................. 2
2. Features .................................................................................. 3
3. Dimensions ............................................................................. 4
4. Refrigeration Cycle Diagram ................................................. 5
5. Wiring diagram ....................................................................... 7
6. Indoor units combination .................................................... 14
7. Sound Levels ........................................................................ 17
8. Installation Details ............................................................... 18
8.1 Wrench torque sheet for installation ........................................................................... 18
8.2 Connecting the cables ................................................................................................ 18
8.3 Pipe length and the elevation ..................................................................................... 18
8.4 Installation for the first time ......................................................................................... 19
8.5 Adding the refrigerant after running the system for many years ................................ 22
8.6 Re-installation while the indoor unit need to be repaired ........................................... 23
8.7 Re-installation while the outdoor unit need to be repaired ......................................... 24
9. Electronic control function .................................................. 27
10. Troubleshooting ................................................................. 32
Caution: Risk of fire/flammable materials

1.
General information of Outdoor Units
Model name Dimension (mm) Compressor
M2OG-14HFN8-Q 800x333x554
KSN140D21UFZ
M2OC-18HFN8-Q 800x333x554
KSM135D23UFZ
M2OD-18HFN8-Q 800x333x554
KSN140D21UFZ
M3OF-21HFN8-Q 845x363x702
KSN140D21UFZ
M3OE-27HFN8-Q 845x363x702
KTF235D22UMT
M3OF-27HFN8-Q 845x363x702
KTM240D57UMT
M4OB-36HFN8-Q 946x410x810
KTF310D43UMT
M4OE-28HFN8-Q 946x410x810
KTM240D57UMT
M5OD-42HFN8-Q 946x410x810
KTF310D43UMT
M5OE-42HFN8-Q 946x410x810
KTF310D43UMT

2.
Features
The hydrophilic fin can improve the heating efficiency at operation mode.
It protects the valves and prevents water from dripping.
4 way valve control
It is only operated in the heating operation mode except defrosting operation.
Outdoor unit
Power relay control
Hydrophilic aluminum fin
Anti-rust cabinet
Valve protection cover
Low noise air flow system
Discharge pipe temperature protection

3.
Dimensions
Model Unit：mm
W D H W1 A B
M2OG-14HFN8-Q 800 333 554 860 514 340
M2OC-18HFN8-Q 800 333 554 860 514 340
M2OD-18HFN8-Q 800 333 554 860 514 340
M3OF-21HFN8-Q 845 363 702 923 540 350
M3OE-27HFN8-Q 845 363 702 923 540 350
M3OF-27HFN8-Q 845 363 702 923 540 350
M4OE-28HFN8-Q 946 410 810 1034 673 403
M4OB-36HFN8-Q 946 410 810 1034 673 403
M5OD-42HFN8-Q 946 410 810 1034 673 403
M5OE-42HFN8-Q 946 410 810 1034 673 403
A
B
D

4.
Refrigeration Cycle Diagram
4.1
Refrigeration circuit drawing of inverter 1 drive 2 type
LIQUID VALVE A
GAS VALVE A
HEAT
EXCHANGE
(EVAPORATOR)
HEAT
EXCHANGE
(CONDENSER)
Compressor
4-WAY VALVE
COOLING
HEATING
T2 Evaporator
temp. sensor
middle
T1 Room
temp. sensor
T3
Condenser
temp. sensor
T5 Discharge
temp. sensor
T4 Ambient
temp. sensor
INDOOR OUTDOOR
EXV A CAPILLARY A
CHECK VALVE
CAPILLARY TUBE
EXV B CAPILLARY B
LIQUID VALVE B
GAS VALVE B
Accumulator
T2B-A
Evaporator
temp. sensor outlet
T2B-B
4.2 Refrigeration circuit drawing of inverter 1 drive 3 type
LIQUID VALVE A
GAS VALVE A
HEAT
EXCHANGE
(EVAPORATOR)
HEAT
EXCHANGE
(CONDENSER)
Compressor
4-WAY VALVE
COOLING
HEATING
T2 Evaporator
temp. sensor
middle
T1 Room
temp. sensor
T3
Condenser
temp. sensor
T5 Discharge
temp. sensor
T4 Ambient
temp. sensor
EXV A CAPILLARY A
CHECK VALVE
CAPILLARY TUBE
EXV B CAPILLARY B
LIQUID VALVE B
GAS VALVE B
EXV C CAPILLARY C
LIQUID VALVE C
GAS VALVE C
Accumulator
T2B-A
Evaporator
temp. sensor outlet
T2B-B
T2B-C

4.3 Refrigeration circuit drawing of inverter 1 drive 4 type
LIQUID VALVE A
GAS VALVE A
HEAT
EXCH ANGE
(EVAP ORATOR)
HEAT
EXCHANGE
(CONDENSER)
Compressor
4-WAY VALVE
COO LING
HEATING
T2 Evaporator
temp. sensor
middle
T1 Room
temp. sensor
T3
Condenser
temp. sensor
T5 Discharge
temp. sensor
T4 Ambient
temp. sensor
INDOOR OUTDOOR
EXV A CAPILLARY A
CHECK VALVE
CAPILLARY TUBE
EXV B CAPILLARY B
LIQUID VALVE B
GAS VALVE B
EXV C CAPILLA RY C
LIQUID VALVE C
GAS VALVE C
EXV D CAPILLA RY D
LIQUID VALVE D
GAS VALVE D
Accumulator
High pressure
switch
Low pressure
switch
T2B-A Evapora tor
temp. sensor outlet
T2B-B
T2B-C
T2B-D
4.4 Refrigeration circuit drawing of inverter 1 drive 5 type
LIQUID VALVE A
GAS VALVE A
HEAT
EXCHANGE
(EVAPORATOR) HEAT
EXCHANGE
(CONDENSER)
COOLING
HEATING
T2 Evaporator
temp. sensor
middle
T1 Room
temp. sensor
T3
Condenser
temp. sensor
T4 Ambient
temp. sensor
INDOOR OUTDOOR
EXV A CAPILLARY A
CHECK VALVE
CAPILLARY TUBE
EXV B CAPILLARY B
LIQUID VALVE B
GAS VALVE B
EXV C CAPILLARY C
LIQUID VALVE C
GAS VALVE C
EXV D CAPILLARY D
LIQUID VALVE D
GAS VALVE D
EXV E CAPILLARY E
LIQUID VALVE E
GAS VALVE E
Compressor
4-WAY VALVE
T5 Discharge
temp. sensor
Accumulator
High pressure
switch
Low pressure
switch
T2B-A
Evaporator
temp. sensor outlet
T2B-B
T2B-C
T2B-D
T2B-E

5.
Wiring diagram
M2OC-18HFN8-Q
M2OG-14HFN8-Q

M2OD-18HFN8-Q

Note: S(1)&S(2) are used in other type of models. They don't need to be connected in multi
models.

M3OE-27HFN8-Q

M3OF-21HFN8-Q, M3OF-27HFN8-Q
M4OE-28HFN8-Q

M4OB-36HFN8-Q

M5OD-42HFN8-Q, M5OE-42HFN8-Q

6.
Indoor units combination
6.1 Indoor unit combination for M2OG-14HFN8-Q
One unit Two unit
7 7+7 9+9
9 7+9 9+12
12 7+12
18
6.2 Indoor unit combination for M2OC-18HFN8-Q&M2OD-18HFN8-Q
One unit Two unit
7 7+7 9+9
9 7+9 9+12
12 7+12 12+12
18
6.3 Indoor unit combination for M3OE-21HFN8-Q
One unit Two unit Three unit
7 7+7 9+9 7+7+7 7+9+9
9 7+9 9+12 7+7+9 9+9+9
12 7+12 9+18 7+7+12
18 7+18 12+12
6.4 Indoor unit combination for M3OE-27HFN8-Q&M3OF-27HFN8-Q
One unit Two unit Three unit
7 7+7 7+18 9+18 7+7+7 7+9+12 9+12+12
9 7+9 9+9 12+12 7+7+9 7+12+12 12+12+12
12 7+12 9+12 12+18 7+7+12 9+9+9
18 7+9+9 9+9+12
6.5 Indoor unit combination for M4OE-28HFN8-Q
One unit
Two unit Three unit Four unit
7 7+7 9+9 12+18 7+7+7 7+9+12 9+9+18 7+7+7+7 7+7+9+12
9 7+9 9+12 12+24 7+7+9 7+9+18 9+12+12 7+7+7+9 7+9+9+9
12 7+12 9+18 18+18 7+7+12 7+12+12 12+12+12 7+7+7+12 9+9+9+9
18 7+18 9+24 7+7+18 9+9+9 7+7+9+9
24 7+24 12+12 7+9+9 9+9+12

6.6 Indoor unit combination for M4OB-36HFN8-Q
If one of indoor units is ATW,
Note: ATW can only be connected with an A system.
One unit
Two unit Three unit Four unit
7 7+7 9+18 7+7+7 7+9+12 7+18+18 9+12+18 7+7+7+7 7+7+9+12 7+9+9+12 9+9+9+12
9 7+9 9+24 7+7+9 7+9+18 9+9+9 9+12+24 7+7+7+9 7+7+9+18 7+9+9+18 9+9+9+18
12 7+12 12+12 7+7+12 7+9+24 9+9+12 9+18+18 7+7+7+12 7+7+12+12 7+9+12+12 9+9+12+12
18 7+18 12+18 7+7+18 7+12+12 9+9+18 12+12+12 7+7+7+18 7+7+12+18 7+12+12+12 9+12+12+12
24 7+24 12+24 7+7+24 7+12+18 9+9+24 12+12+18 7+7+9+9 7+9+9+9 9+9+9+9 12+12+12+12
9+9 18+18 7+9+9 7+12+24 9+12+12
9+12
One unit
Two unit Three unit Four unit
7
7+ATW 7+7+ATW 9+12+ATW 7+7+7+ATW 7+9+12+ATW 9+12+12+ATW
9
9+ATW 7+9+ATW 9+18+ATW 7+7+9+ATW 7+9+18+ATW 9+12+18+ATW
12
12+ATW 7+12+ATW 12+12+ATW 7+7+12+ATW 9+9+9+ATW 12+12+12+ATW
18
18+ATW 7+18+ATW 12+18+ATW 7+7+18+ATW 9+9+12+ATW 12+12+18+ATW
ATW
9+9+ATW 18+18+ATW 7+9+9+ATW 9+9+18+ATW

6.7 Indoor unit combination for M5OD-42HFN8-Q, M5OE-42HFN8-Q
One Unit Two Unit Three Unit
7 7+7 9+18 7+7+7 7+9+18 9+9+12 12+12+12
9 7+9 9+24 7+7+9 7+9+24 9+9+18 12+12+18
12 7+12 12+12 7+7+12 7+12+12 9+9+24 12+12+24
18 7+18 12+18 7+7+18 7+12+18 9+12+12 12+18+18
24 7+24 12+24 7+7+24 7+12+24 9+12+18
9+9 18+18 7+9+9 7+18+18 9+12+24
9+12 7+9+12 9+9+9 9+18+18
Four Unit
7+7+7+7 7+7+9+18 7+9+9+12 7+12+12+12 9+9+12+18
7+7+7+9 7+7+9+24 7+9+9+18 7+12+12+18 9+9+12+24
7+7+7+12 7+7+12+12 7+9+9+24 9+9+9+9 9+12+12+12
7+7+7+18 7+7+12+18 7+9+12+12 9+9+9+12 9+12+12+18
7+7+7+24 7+7+12+24 7+9+12+18 9+9+9+18 12+12+12+12
7+7+9+9 7+7+18+18 7+9+12+24 9+9+9+24 12+12+12+18
7+7+9+12 7+9+9+9 7+9+18+18 9+9+12+12
Five Unit
7+7+7+7+7 7+7+7+9+18 7+7+9+12+12 7+9+9+9+18 9+9+9+12+12
7+7+7+7+9 7+7+7+12+12 7+7+9+12+18 7+9+9+12+12 9+9+12+12+12
7+7+7+7+12 7+7+7+12+18 7+7+12+12+12 7+9+12+12+12
7+7+7+7+18 7+7+9+9+9 7+7+12+12+18 9+9+9+9+9
7+7+7+9+9 7+7+9+9+12 7+9+9+9+9 9+9+9+9+12
7+7+7+9+12 7+7+9+9+18 7+9+9+9+12 9+9+9+9+18

7.
Sound Levels
Note: H= 0.5 × height of outdoor unit
Model Noise Power dB(A) Noise level dB(A)
M2OG-14HFN8-Q 64 57
M2OC-18HFN8-Q 56 53
M2OD-18HFN8-Q 65 55.5
M3OF-21HFN8-Q 66 57.5
M3OE-27HFN8-Q 65 59
M3OF-27HFN8-Q 67 59.5
M4OE-28HFN8-Q 69 61
M4OB-36HFN8-Q 68 63
M5OD-42HFN8-Q 71 62
M5OE-42HFN8-Q 70 63
H
1.0m
Outdoor Unit
Microphone

8.
Installation Details
8.1 Wrench torque sheet for installation
Outside diameter Torque Additional tightening torque
mm N.cm N.cm
Ф6.35 1500(153kgf.cm) 1600(163kgf.cm)
Ф9.52 2500(255kgf.cm) 2600(265kgf.cm)
Ф12.7 3500(357kgf.cm) 3600(367kgf.cm)
8.2 Connecting the cables
The power cord of connect should be selected according to the following specifications sheet.
Rated current of appliance Nominal cross-sectional area (mm²)
>3 and ≤6 0.75
>6 and ≤10 1
>10 and ≤16 1.5
>16 and ≤25 2.5
The cable size and the current of the fuse or switch are determined by the maximum current indicated on the
nameplate which located on the side panel of the unit. Please refer to the nameplate before selecting the
cable, fuse and switch.
8.3 Pipe length and the elevation
Maximum piping length and height difference
1 drive 2 1 drive 3 1 drive 4 1 drive 5
Max. length for all rooms (m) 40 60 80 80
Max. length for one IU (m) 25 30 35 35
Max. height difference between IU and OU (m) 15 15 15 15
Max. height difference between IUs (m) 10 10 10 10
Additional refrigerant charge
Connective Pipe Length(m) Additional refrigerant
Liquid Side Ø 6.35 (1/4”) Ø 9.52 (3/8”)
Pre-charge pipe length (ft/m)
(pre-charge pipe length xN ) N/A
More than (pre-charge pipe lengthxN) ft/m
(Total pipe length - pre-charge pipe
lengthxN) x12g/m
(Total pipe length - pre-charge pipe
lengthxN) x24g/m
(Total pipe length - pre-charge pipe
lengthxN) x0.13oZ/ft
(Total pipe length - pre-charge pipe
lengthxN) x0.26oZ/ft
Caution:
● Refrigerant pipe diameter is different according to indoor unit to be connected. When using the
extension pipe, refer to the tables below.

● When refrigerant pipe diameter is different from that of outdoor unit union (for 18K&24K indoor unit),
additional transfer connector needs to be used on outdoor unit union.
Indoor unit Extension pipe diameter (mm/inch)
Model Pipe diameter (mm/inch)
7K9K12K
Liquid 6.35(1/4) Liquid 6.35(1/4)
Gas 9.52(3/8) Gas 9.52(3/8)
18K
Liquid 6.35(1/4) Liquid 6.35(1/4)
Gas 12.7(1/2) Gas 12.7(1/2)
24K Liquid 9.52(3/8) Liquid 9.52(3/8)
Gas 15.9(5/8) Gas 15.9(5/8)
Outdoor unit union diameter (mm/inch)
1 drive 2
Liquid 6.35(1/4)
*2
Gas
9.52(3/8)
*2
1 drive 3
Liquid 6.35(1/4)
*3
Gas
9.52(3/8)
*3
1 drive 4
Liquid 6.35(1/4)
*4
Gas
9.52(3/8)
*3
12.7(1/2)
*
1
1 drive 5
Liquid 6.35(1/4)
*5
Gas
9.52(3/8)
*4
12.7(1/2)
*
1
8.4 Installation for the first time
Air and moisture in the refrigerant system have undesirable effects as below:
● Pressure in the system rises.
● Operating current rises.
● Cooling or heating efficiency drops.
● Moisture in the refrigerant circuit may freeze and block capillary tubing.
● Water may lead to corrosion of parts in the refrigerant system.
Therefore, the indoor units and the pipes between indoor and outdoor units must be leak tested and
evacuated to remove gas and moisture from the system.
Gas leak check (Soap water method):
Apply soap water or a liquid neutral detergent on the indoor unit connections or outdoor unit connections
by a soft brush to check for leakage of the connecting points of the piping. If bubbles come out, the pipes
have leakage.
1. Air purging with vacuum pump