Midea M2OC-18HRDN1-M, M3OC-27HRDN1-M, M4OC-36HRDN1-M Service Manual

ODMI-A-1110

SERVICE MANUAL

MIDEA AIRCONDITIONER

North America MARKET

DC INVERTER MULTI TYPE

M2OC-18HRDN1-M
M3OC-27HRDN1-M
M4OC-36HRDN1-M

DC MULTI OUTDOOR UNITS

ODMI-A-1110

CONTENTS

1. General information of Outdoor Units ................................................. 3

2.Features .................................................................................................. 4

3. Dimensions ............................................................................................ 5

4. Wiri ng Diagram ...................................................................................... 6

5. Refrigeration Cycle Diagram ................................................................ 8

6. I ndoor units combination .................................................................... 10

7. I nstallation De tails ............................................................................... 11

8. Electronic control function ................................................................. 20

9. Troubleshooting .................................................................................. 25

ODMI-A-1110

1. General information of Outdoor Unit s

Model name Dimension (mm(in)) Compressor

M2OC-18HRDN1-M 845x320x700(33.3x12.6x27.6) DA130S1C-20FZ
M3OC-27HRDN1-M 845x320x700(33.3x12.6x27.6) DA150S1C-20FZ
M4OC-36HRDN1-M 990x345x965(39x13.6x38) TNB306FPGMC-L

ODMI-A-1110

2．Features

The hydrophilic fin can improve the heating efficiency at operation mode.

It is only operated in the heating operation mode except defrosting operation.

It protects the valves and prevents water from dripping.

Outdoor unit

Power relay control

Hydrophilic aluminum fin

Anti-rust cabinet

Valve protection cover

4 way valve control

Low noise air flow system

Discharge pipe temperature protection

Compressor crankcase heater

ODMI-A-1110

3. Dimensions

mm(in)

Model W D H W1 A B

M2OC-18HRDN1-M

845((33.3) 320(12.6) 700(27.6) 908(35.7) 560(22) 335(13.2)

M3OC-27HRDN1-M
M4OC-36HRDN1-M 990(39) 345(13.6) 965(38) 1075(42.3) 624(24.6) 366(14.4)

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4. Wiring Diagram

4.1 M2OC-18HRDN1-M

4.2 M3OC-27HRDN1-M

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4.3 M4OC-36HRDN1-M

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5. Refrigeration Cycle Diagram

8.1 Refrigeration circuit drawing of inverter dual zone

5.2 Refrigeration circuit drawing of inverter tri-zone

8.3 Refrigeration circuit drawing of inve r t e r qua-zone

Liquid valve A

Gas valve C

EXV C

4

-

way

valve

Compressor

Condenser

Axial flow fan

EXV B

EXV A

Gas valve A

Gas valve B

Liquid valve C

Liquid valve B

Evaporator

Cross

flow fan

Indoor Unit

Capillary A

Capillary B

Capillary C

Filter A

Filter B

Filter C

Main

Capillary

Auxiliary

Capillary

Check

Valve

Exhaust

temp. sensor

Indoor pipe out

temp.

sens

or B

Indoor pipe out

temp. sen

sor A

Indoor pipe out

temp. sen

s

or C

Outdoor Unit

Coil temp.

sensor

Indoor Unit

Cross flow fan

Evaporator

Liquid valve A

Liquid valve B

Gas valve B

Gas valve A

EXVA

EXVB

Axial flow fan

Condenser

Compressor

4

-

way

valve

Auxiliary

Capillary

Capillary A

Capillary B

Exhaust

temp. sensor

Indoor pipe out

temp. sen

s

or A

Indoor pipe out

temp. sen

s

or B

Filter A

Filter B

Outdoor Unit

Main

Capillary

Check

Valve

Coil temp.

sensor

ODMI-A-1110

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6. Indoor units combination

6.1 Indoor unit combination for M2OC-18HRDN1-M

Comb.

Combinations

Unit A

Unit B

Dual(1x1)

9k

—

12k — 18k

—

Dual (1x2)

9k

9k

9k

12k

12k

12k

6.2 Indoor unit combination for M3OC-27HRDN1-M

Comb.

Combinations

Unit A

Unit B

Unit C

TRI (1x1)

9k

—

—

12k

—

—

18k

—

—

TRI (1x2)

9k

9k

—

9k

12k

—

9k

18k

—

12k

12k

—

12k

18k

—

TRI (1x3)

9k

9k

9k

9k

9k

12k

9k

12k

12k

6.3 Indoor unit combination for M4OC-36HRDN1-M

Comb.

Combinations

Unit A

Unit B

Unit C

Unit D

QUA (1x1)

9k

— — —

12k

— — —

18k

— — —

QUA (1x2)

9k

9k

—

—

9k

12k

—

—

9k

18k

—

—

12k

12k

—

—

12k

18k

—

—

18k

18k

—

—

QUA (1x3)

9k

9k

9k

—

9k

9k

12k

—

9k

9k

18k

—

9k

12k

12k

—

9k

12k

18k

—

9k

18k

18k

—

12k

12k

12k — 12k

12k

18k

—

12k

18k

18k

—

QUA(1x4)

9k

9k

9k

9k

9k

9k

9k

12k

9k

9k

9k

18k

9k

9k

12k

12k

9k

9k

12k

18k

9k

12k

12k

12k

9k

12k

12k

18k

12k

12k

12k

12k

12k

12k

12k

18k

ODMI-A-1110

7. Installation Details

7.1 Wrench torque sheet for installation

Outside diameter Torque Additional tightening torque

mm inch N.cm N.cm
$6.35 1/4 1500(153kgf.cm) 1600(163kgf.cm)
$9.52 3/8 2500(255kgf.cm) 2600(265kgf.cm)
$12.7 1/2 3500(357kgf.cm) 3600(367kgf.cm)

7.2 Connecting the cables

The power cord of connect s houl d be selected according to the follow ing specifications sheet.

For power line:

Unit AWG

dual-zone(18K outdoor unit) 14

tri-zone (27K outdoor unit). 14
qua-zone(36K outdoor unit) 12

For indoor unit and outdoor unit connection line, 16AWG is ok for all.

7.3 Pipe length and the elevation

Unit

Pipe size

Standard

length

(m)

Max.

Elevation

B (m)

Max.

Length

A (m)

Additional
refrigerant

(g/m)

Gas Liquid

9K 3/8•• ($9.53) 1/4•• ($6.35)

5

(16.4ft)

8

(26.2ft)

20

(65.6ft)

20

(0.212
ozs/ft)

12K/18K 1/2•• ($12.7) 1/4•• ($6.35)

Caution:

Capacity test is based o n standard length and maxi mu m allowance length is based on rel iability.
Oil trap should be install ed per 3-5 meters.

ODMI-A-1110

7.4 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 drop s.

● Moisture in the refrigerant circuit may freeze and block capillary t ubing.

● Water may lead to corrosion of par ts in the refrigerant syst em.

Therefore, the indoor units and t he pipes between i ndoor and out d oor unit s m ust be lea k tested and

evacuated to remove gas and mo ist ur e 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 pur ging with vacuum pum p

1) Completely tighten the flare nuts of the indoor and outdoor units, confirm that both the 2-way and

3-way valves are set to the closed position.

2) Connect the charge hose w it h t he push pin of handle lo to the 3-way valves gas service port..

3) Connect the charge hose of ha ndle hi connection to the vacuu m pu mp.

4) Fully open the handle Lo of the ma ni fold valve.

5) Operate the vacuum pum p t o evacuate.

6) Make evacuation for 30 minutes and check whether the compound meter indicates -0.1Mpa. If
the meter does not indicate -0.1Mpa after pumping 30 minutes, it sh oul d be pumped 20 minutes more. If

the pressure can’t achieve -0.1Mpa after pumping 50 minutes, please check if there are some leakage

(Indoor unit)

(Liquid side)

(Gas side)

Vacuum

pump

Vacuum

pump

Lo

Hi

Handle Hi

Two

-way valve

Close

Manifold valve

Compound meter

Pressure

gauge

20Pa

Handle Lo

Charge hose

Charge hose

(Outdoor unit)

Close

Three-way valve