Midea M2OC-18HRDN1-M User 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.Wiring Diagram......................................................................................6
5.Refrigeration Cycle Diagram ................................................................8
6.Indoor units combination....................................................................10
7.Installation Details...............................................................................11
8.Electronic control function.................................................................20
9.Troubleshooting..................................................................................25

ODMI-A-1110
1. General information of Outdoor Units
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

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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

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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 inverter 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

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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
6.2Indoor 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
6.3Indoor 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

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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 should be selected according to the following 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 on standard length and maximum allowance length is based on reliability.
Oil trap should be installed per 3-5 meters.

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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 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
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 with the push pin of handle lo to the 3-way valves gas service port..
3) Connect the charge hose of handle hi connection to the vacuum pump.
4) Fully open the handle Lo of the manifold valve.
5) Operate the vacuum pump to 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 should 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

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points.
Fully close the handle Lo valve of the manifold valve and stop the operation of the vacuum pump.
Confirm that the gauge needle does not move (approximately 5 minutes after turning off the vacuum
pump).
7) Turn the flare nut of the 3-way valves about 45° counterclockwise for 6 or 7seconds after the gas
coming out, and then tighten the flare nut again. Make sure the pressure display in the pressure
indicator is a little higher than the atmosphere pressure. Then remove the charge hose from the 3
way valve.
8) Fully open the 2 way valve and 3 way valve and securely tighten the cap of the 3 way valve.
2. Air purging by refrigerant
Procedure:
1). Confirm that both the 2-way and 3-way valves are set to the closed position.
2). Connect the charge set and a charging cylinder to the service port of the 3-way valve.
3).Air purging.
Open the valves on the charging cylinder and the charge set. Purge the air by loosening the flare nut on
the 2-way valve approximately 45’ for 3 seconds then closing it for 1 minute; repeat 3 times.
After purging the air, use a torque wrench to tighten the flare nut on the 2-way valve.
4). Check the gas leakage.
Check the flare connections for gas leakage.
5). Discharge the refrigerant.
Close the valve on the charging cylinder and discharge the refrigerant by loosening the flare nut on the

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2-way valve approximately 45’ until the gauge indicates 0.3 to 0.5 Mpa.
6). Disconnect the charge set and the charging cylinder, and set the 2-way and 3-way valves to the open
position.
Be sure to use a hexagonal wrench to operate the valve stems.
7). Mount the valve stems nuts and the service port cap.
Be sure to use a torque wrench to tighten the service port cap to a torque 18N·m.
Be sure to check the gas leakage.
3. Adding the refrigerant if the pipe length >5m
Procedure:
1). Connect the charge hose to the charging cylinder, open the 2-way valve and the 3-way valve.
Connect the charge hose which you disconnected from the vacuum pump to the valve at the bottom of
the cylinder. If the refrigerant is R410A, make the cylinder bottom up to ensure the liquid charge.
2). Purge the air from the charge hose.
Open the valve at the bottom of the cylinder and press the check valve on the charge set to purge the air
(be careful of the liquid refrigerant).
3) Put the charging cylinder onto the electronic scale and record the weight.
4) Operate the air conditioner at the cooling mode.
5) Open the valves (Low side) on the charge set and charge the system with liquid refrigerant.
6).When the electronic scale displays the proper weight (refer to the table), disconnect the charge hose
Electronic scale

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from the 3-way valve’s service port immediately and turn off the air conditioner before disconnecting the
hose.
7). Mount the valve stem caps and the service port
Use torque wrench to tighten the service port cap to a torque of 18N.m.
Be sure to check for gas leakage.
7.5 Adding the refrigerant after running the system for many years
Procedure:
1). Connect the charge hose to the 3-way service port, open the 2-way valve and the 3-way valve.
Connect the charge hose to the valve at the bottom of the cylinder. If the refrigerant is R410A, make the
cylinder bottom up to ensure liquid charge.
2). Purge the air from the charge hose.
Open the valve at the bottom of the cylinder and press the check valve on the charge set to purge the air
(be careful of the liquid refrigerant).
3) Put the charging cylinder onto the electronic scale and record the weight.
4) Operate the air conditioner at the cooling mode.
5) Open the valves (Low side) on the charge set and charge the system with liquid refrigerant.
6).When the electronic scale displays the proper weight (refer to the gauge and the pressure of the low
side), disconnect the charge hose from the 3-way valve’s service port immediately and turn off the air
conditioner before disconnecting the hose.
Electronic scale

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7). Mount the valve stem caps and the service port
Use torque wrench to tighten the service port cap to a torque of 18N.m.
Be sure to check for gas leakage.
7.6 Re-installation while the indoor unit need to be repaired
1. Collecting the refrigerant into the outdoor unit
Procedure
1). Confirm that both the 2-way and 3-way valves are set to the opened position
Remove the valve stem caps and confirm that the valve stems are in the opened position.
Be sure to use a hexagonal wrench to operate the valve stems.
2). Connect the charge hose with the push pin of handle lo to the 3-way valves gas service port.
3).Air purging of the charge hose.
Open the handle Lo valve of the manifold valve slightly to purge air from the charge hose for 5 seconds
and then close it quickly.
4). Set the 2-way valve to the close position.
5). Operate the air conditioner at the cooling cycle and stop it when the gauge indicates 0.1MPa.
6). Set the 3-way valve to the closed position immediately
Do this quickly so that the gauge ends up indicating 0.3 to 0.5Mpa.
Disconnect the charge set, and tighten the 2-way and 3-way valve’s stem nuts.

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Use a torque wrench to tighten the 3-way valves service port cap to a torque of 1.8 kgf.m.
Be sure to check for gas leakage.
2. Air purging by the refrigerant
Procedure:
1). Confirm that both the 2-way and 3-way valves are set to the closed position.
2). Connect the charge set and a charging cylinder to the service port of the 3-way valve
Leave the valve on the charging cylinder closed.
3).Air purging.
Open the valves on the charging cylinder and the charge set. Purge the air by loosening the flare nut on
the 2-way valve approximately 45’ for 3 seconds then closing it for 1 minute; repeat 3 times.
After purging the air, use a torque wrench to tighten the flare nut on the 2-way valve.
4). Check the gas leakage
Check the flare connections for gas leakage.
5). Discharge the refrigerant.
Close the valve on the charging cylinder and discharge the refrigerant by loosening the flare nut on the
2-way valve approximately 45’ until the gauge indicates 0.3 to 0.5 Mpa.
6). Disconnect the charge set and the charging cylinder, and set the 2-way and 3-way valves to the open
position

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Be sure to use a hexagonal wrench to operate the valve stems.
7). Mount the valve stems nuts and the service port cap
Be sure to use a torque wrench to tighten the service port cap to a torque 18N.m.
Be sure to check the gas leakage.
7.7 Re-installation while the outdoor unit need to be repaired
1. Evacuation for the whole system
Procedure:
1). Confirm that both the 2-way and 3-way valves are set to the opened position.
2). Connect the vacuum pump to 3-way valve’s service port.
3). Evacuation for approximately one hour. Confirm that the compound meter indicates -0.1Mpa.
4). Close the valve (Low side) on the charge set, turn off the vacuum pump, and confirm that the gauge
needle does not move (approximately 5 minutes after turning off the vacuum pump).
5). Disconnect the charge hose from the vacuum pump.

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2. Refrigerant charging
Procedure:
1). Connect the charge hose to the charging cylinder; open the 2-way valve and the 3-way valve
Connect the charge hose which you disconnected from the vacuum pump to the valve at the bottom of
the cylinder. If the refrigerant is R410A, make the cylinder bottom up to ensure liquid charge.
2). Purge the air from the charge hose
Open the valve at the bottom of the cylinder and press the check valve on the charge set to purge the air
(be careful of the liquid refrigerant).
3) Put the charging cylinder onto the electronic scale and record the weight.
4). Open the valves (Low side) on the charge set and charge the system with liquid refrigerant
If the system cannot be charge with the specified amount of refrigerant, or can be charged with a little at
a time (approximately 150g each time) , operating the air conditioner in the cooling cycle; however, one
time is not sufficient, wait approximately 1 minute and then repeat the procedure.
5).When the electronic scale displays the proper weight, disconnect the charge hose from the 3-way
valve’s service port immediately
If the system has been charged with liquid refrigerant while operating the air conditioner, turn off the air
conditioner before disconnecting the hose.
6). Mounted the valve stem caps and the service port
Use torque wrench to tighten the service port cap to a torque of 18N.m.
Be sure to check for gas leakage

8. Electronic control function
8.1 Abbreviation
T1: Indoor ambient temperature
T2: Coil temperature of indoor heat exchanger middle.
T2B: Coil temperature of indoor heat exchanger outlet.
T3: Coil temperature of outdoor heat exchanger
T4: Outdoor ambient temperature
T5: Compressor discharge temperature
Ts: Setting temp.
8.2 Electric control working environment.
8.2.1 Input voltage: 230V.
8.2.2 Input power frequency:60Hz.
8.2.3 Indoor fan normal working amp. is less than 1A.
8.2.4 Outdoor fan. Normal working amp. is less than 1.5A.
8.2.5 Four-way valve normal working amp. is less than 1A.
8.2.6 Swing motor: DC12V.
8.3 Outdoor unit’s digital display tube
There is a digital display tube in outdoor PCB.
Digital display tube display function
•In standby , the LED displays “- -”
•In compressor operation, the LED display the running frequency,
•In defrosting mode, The LED displays “dF” or alternative displays between running frequency and
“dF”(each displays 2s)
•In compressor pre-heating, The LED displays “- -”
•In protection or malfunction, the LED displays error code or protection code.
8.4 Outdoor unit point check function
There is a check switch in outdoor PCB.
Push the switch SW1 to check the states of unit when the unit is running. The digital display tube will display
the follow procedure when push SW1 each time.
Display
Remark
1
Indoor unit capacity demand code
2
Outdoor unit running mode code
Off:0, Cooling:1, Heating:2
3
Amendatory capacity demand code
4
Outdoor unit fan motor state
Off:0, Low speed:1, High speed:2
5
Evaporator outlet temp. for 1# indoor unit
Actual data
6
Evaporator outlet temp. for 2# indoor unit
Actual data
7
Evaporator outlet temp. for 3# indoor unit
Actual data
8
Evaporator outlet temp. for 4# indoor unit
Actual data
9
Condenser pipe temp.
Actual data
10
Ambient temp.
Actual data
11
Compressor discharge temp.
Actual data
12
Inverter current
Actual data
13
EXV open angle for 1# indoor unit
Actual data divide 8