Midea MV6-i252WV2GN1-E, MV6-i450WV2GN1-E, MV6-i280WV2GN1-E, MV6-i335WV2GN1-E, MV6-i400WV2GN1-E Service Manual

Commercial Air Conditioners
R410A

Series

MV6-i252WV2GN1-E

MV6-i280WV2GN1-E

MV6-i335WV2GN1-E

MV6-i400WV2GN1-E

MV6-i450WV2GN1-E

MV6-i500WV2GN1-E

MV6-i560WV2GN1-E

MV6-i615WV2GN1-E

MV6-i670WV2GN1-E

MV6-i730WV2GN1-E

MV6-i785WV2GN1-E

MV6-i850WV2GN1-E

MV6-i900WV2GN1-E

Service
Manual

V6-i VRF 50/60Hz

CONTENTS

CONTENTS

Part 1 General Information ............................................................................ 3

Part 2 Component Layout and Refrigerant Circuits ................................... 11

Part 3 Control ............................................................................................... 33

Part 4 Field Settings ..................................................................................... 49

Part 5 Electrical Components and Wiring Diagrams .................................. 55

Part 6 Diagnosis and Troubleshooting ......................................................... 69

1

V5 X VRF 50/60Hz

Midea V6-i Series Service Manual

2

V6-i VRF 50/60Hz

Part 1

- General Information

Part 1

General Information

1 Indoor and Outdoor Unit Capacities .................................................. 4

2 External Appearance ............................................................................ 6

3 Combination Ratio ................................................................................ 8

3

V6-i VRF 50/60Hz

Midea V6-i Series Engineering Data Book

Abbreviation

code

Type

Abbreviation

code

Type

Q1

One-way Cassette

T1

High Static Pressure Duct

Q2

Two-way Cassette

G

Wall-mounted

Q4C

Compact Four-way Cassette

DL

Ceiling & Floor

Q4

Four-way Cassette

F

Floor Standing

T2

Medium Static Pressure Duct

Z

Console

Capacity

Capacity

index

Q1

Q2

Q4C

Q4

T2

T1 G DL F Z

kW

HP

1.8

0.6

18

18

— — — — — — —

18 — 2.2

0.8

22

22

22

22 — 22 — 22 — 22

22

2.8 1 28

28

28

28

28

28 — 28 — 28

28

3.6

1.25

36

36

36

36

36

36 — 36

36

36

36

4.5

1.6

45

45

45

45

45

45 — 45

45

45

45

5.6 2 56

56

56 — 56

56 — 56

56

56 — 7.1

2.5

71

71

71 — 71

71

71

71

71

71 — 8.0 3 80

— — —

80

80

80

80

80

80 — 9.0

3.2

90

— — —

90

90

90

90

90

90 — 10.0

3.6

100

— — —

100

— — — — —

—

11.2 4 112

— — —

112

112

112 — 112

—

—

14.0 5 140

— — —

140

140

140 — 140

—

—

16.0 6 160

— — — — —

160 — 160

—

—

20.0 7 200

— — — — —

200

— — —

—

25.0 9 250

— — — — —

250

— — —

—

28.0

10

280

— — — — —

280

— — —

—

40.0

14

400

— — — — —

400

— — —

—

45.0

16

450

— — — — —

450

— — —

—

56.0

20

560

— — — — —

560

— — —

—

Capacity

12.5kW

14kW

20kW

25kW

28kW

Capacity index

125

140

200

250

280

Capacity

200m3/h

300m3/h

400m3/h

500m3/h

800m3/h

1000m3/h

1500m3/h

2000m3/h

1 Indoor and Outdoor Unit Capacities

1.1 Indoor Units

1.1.1 Standard indoor units

Table 1-1.1: Standard indoor unit abbreviation codes

Table 1-1.2: Standard indoor unit capacity range

1.1.2 Fresh air processing unit

Table 1-1.3: Fresh air processing unit capacity range

1.2 Heat recovery ventilator

Table 1-1.4: Heat recovery ventilator capacity range

4

V6-i VRF 50/60Hz

Part 1 - General Information

Capacity

Model Name

8HP

MV6-i252WV2GN1-E

10HP

MV6-i280WV2GN1-E

12HP

MV6-i335WV2GN1-E

14HP

MV6-i400WV2GN1-E

16HP

MV6-i450WV2GN1-E

18HP

MV6-i500WV2GN1-E

20HP

MV6-i560WV2GN1-E

22HP

MV6-i615WV2GN1-E

24HP

MV6-i670WV2GN1-E

26HP

MV6-i730WV2GN1-E

28HP

MV6-i785WV2GN1-E

30HP

MV6-i850WV2GN1-E

32HP

MV6-i900WV2GN1-E

1.3 Outdoor Units

Table 1-1.5: Outdoor unit capacity range

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V6-i VRF 50/60Hz

Midea V6-i Series Engineering Data Book

One-way Cassette

Two-way Cassette

Q1 Q2

Compact Four-way Cassette

Four-way Cassette

Q4C

Q4

Medium Static Pressure Duct

High Static Pressure Duct

T2 T1

Wall-mounted

Ceiling & Floor

G DL

Floor Standing

Console

F Z

Fresh Air Processing Unit

FA

Heat Recovery Ventilator

2 External Appearance

2.1 Indoor Units

2.1.1 Standard indoor units

Table 1-2.1: Standard indoor unit appearance

2.1.2 Fresh air processing unit

Table 1-2.2: Fresh air processing unit appearance

2.2 Heat Recovery Ventilator

Table 1-2.3: Heat recovery ventilator appearance

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V6-i VRF 50/60Hz

Part 1

- General Information

8/10/12HP

(with single fan)

14/16/18HP

(with single fan)

20/22HP

(with dual fans)

24/26/28/30/32HP

(with dual fans)

2.3 Outdoor Units

Table 1-2.4: Outdoor unit appearance

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V6-i VRF 50/60Hz

Midea V6-i Series Engineering Data Book

Type

Minimum

combination ratio

Maximum combination ratio

Standard indoor

units only

Fresh air processing

units only

Fresh air processing units and

standard indoor units together

V6-i Series outdoor units

50%

130%

100%

100%1

Outdoor unit capacity

Sum of capacity indexes of

connected indoor units (standard

indoor units only)

Sum of capacity indexes of connected indoor

units (fresh air processing units and standard

indoor units together)

Maximum number of

connected indoor

units

kW

HP

Capacity

index

25.2 8 252

126 to 327.6

126 to 252

13

28.0

10

280

140 to 364

140 to 280

16

33.5

12

335

167.5 to 435.5

167.5 to 335

20

40.0

14

400

200 to 520

200 to 400

23

45.0

16

450

225 to 585

225 to 450

26

50.0

18

500

250 to 650

250 to 500

29

56.0

20

560

280 to 728

280 to 560

33

61.5

22

615

307.5 to 799.5

307.5 to 615

36

67.0

24

670

335 to 871

335 to 670

39

73.0

26

730

365 to 949

365 to 730

43

78.5

28

785

392.5 to 1020.5

392.5 to 785

46

85.0

30

850

425 to 1105

425 to 850

50

90.0

32

900

450 to 1170

450 to 900

53

Combination ratio =

Sum of capacity indexes of the indoor units

Capacity index of the outdoor unit

3 Combination Ratio

Table 1-5.1: Indoor and outdoor unit combination ratio limitations

Notes:

1. When fresh air processing units are installed together with standard indoor units, the total capacity of the fresh air processing units must not exceed 30%

of the capacity of the outdoor unit and the combination ratio must not exceed 100%.

Table 1-5.2: Combinations of Indoor and outdoor units

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Part 2

- Component Layout

and

Refrigerant Circuits

Part 2

Component Layout and

Refrigerant Circuits

1 Layout of Functional Components ....................................................... 10

2 Piping Diagrams .................................................................................. 16

3 Refrigerant Flow Diagrams .................................................................. 22

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V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Legend

No.

Parts name

1

Compressor

2

Discharge temperature switch

3

High pressure switch

4

High pressure sensor

5

Oil separator

6

Four-way valve

7

Heat exchanger

8

Electronic expansion valve (EXV)

9

Low pressure switch

10

Fan motor

11

Fan

12

Stop valve (liquid side)

13

Stop valve (gas side)

14

Plate heat exchanger

15

56

7

8

12

13

14

11

9

10

3

4 2

1

1 Layout of Functional Components

8/10/12HP

Figure 2-1.1: 8/10/12 layout of functional components

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Part 2

- Component Layout

and

Refrigerant Circuits

Legend

No.

Parts name

1

Compressor

2

Discharge temperature switch

3

High pressure switch

4

High pressure sensor

5

Oil separator

6

Four-way valve

7

Heat exchanger

8

Electronic expansion valve (EXV)

9

Low pressure switch

10

Fan motor

11

Fan

12

Stop valve (liquid side)

13

Stop valve (gas side)

14

Plate heat exchanger

15

Accumulator

15

5

6

7

8

9

12

13

14

11

9

10

3

4

2

1

14/16/18HP

Figure 2-1.2: 14/16/18 layout of functional components

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V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Legend

No.

Parts name

1

Compressor

2

Discharge temperature switch

3

High pressure switch

4

High pressure sensor

5

Oil separator

6

Four-way valve

7

Heat exchanger

8

Electronic expansion valve (EXV)

9

Low pressure switch

10

Fan motor

11

Fan

12

Stop valve (liquid side)

13

Stop valve (gas side)

15

Accumulator

1556

7

8

9

12

13

11

9

10

3

4

2

1

20/22HP

Figure 2-1.3: 20/22 layout of functional components

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Part 2

- Component Layout

and

Refrigerant Circuits

Legend

No.

Parts name

1

Compressor

2

Discharge temperature switch

3

High pressure switch

4

High pressure sensor

5

Oil separator

6

Four-way valve

7

Heat exchanger

8

Electronic expansion valve (EXV)

9

Low pressure switch

10

Fan motor

11

Fan

12

Stop valve (liquid side)

13

Stop valve (gas side)

15

Accumulator

15

5

4

6

7

8

9

12

13

11

9

10

3

2

1

24HP

Figure 2-1.4: 24 layout of functional components

13

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Legend

No.

Parts name

1

Compressor

2

Discharge temperature switch

3

High pressure switch

4

High pressure sensor

5

Oil separator

6

Four-way valve

7

Heat exchanger

8

Electronic expansion valve (EXV)

9

Low pressure switch

10

Fan motor

11

Fan

12

Stop valve (liquid side)

13

Stop valve (gas side)

14

Plate heat exchanger

15

Accumulator

15

5

4

6

7

8

9

12

13

14

11

9

10

3

2

1

26/28HP

Figure 2-1.5: 26/28 layout of functional components

14

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Part 2

- Component Layout

and

Refrigerant Circuits

Legend

No.

Parts name

1

Compressor

2

Discharge temperature switch

3

High pressure switch

4

High pressure sensor

5

Oil separator

6

Four-way valve

7

Heat exchanger

8

Electronic expansion valve (EXV)

9

Low pressure switch

10

Fan motor

11

Fan

12

Stop valve (liquid side)

13

Stop valve (gas side)

14

Plate heat exchanger

15

Accumulator

15

5

4

6

7

8

9

12

13

14

11

9

10

3

2

1

30/32HP

Figure 2-1.6: 30/32 layout of functional components

15

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Legend

No.

Parts name

No.

Parts name

1

Compressor

14

Plate heat exchanger

2

Discharge temperature switch

15

Accumulator

3

High pressure switch

T3

Heat exchanger temperature sensor

4

High pressure sensor

T4

Outdoor ambient temperature sensor

5

Oil separator

T6A

Plate heat exchanger inlet temperature sensor

6

Four-way valve

T6B

Plate heat exchanger outlet temperature sensor

7

Heat exchanger

T7C1

Compressor A discharge temperature sensor

8

Electronic expansion valve (EXV)

T7C2

Compressor B discharge temperature sensor

9

Low pressure switch

SV4

Oil return valve

10

Fan motor

SV5

Fast defrosting (in heating) and unloading (in cooling) valve

11

Fan

SV6

Refrigerant bypass EXV valve

12

Stop valve (liquid side)

SV8A

Compressor A vapor injection valve

13

Stop valve (gas side)

7

1

15 12

9

3

2

4

5

6

11

10

14

8

8

13

EXVA

EXVC

E

S

C

T3

T4

T6B

T7C1

T7C2

T6A

SV8A

SV4

SV5

SV6

2 Piping Diagrams

8/10/12HP

Figure 2-2.1: 8/10/12HP piping diagram

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Part 2

- Component Layout

and

Refrigerant Circuits

Legend

No.

Parts name

No.

Parts name

1

Compressor

14

Plate heat exchanger

2

Discharge temperature switch

15

Accumulator

3

High pressure switch

T3

Heat exchanger temperature sensor

4

High pressure sensor

T4

Outdoor ambient temperature sensor

5

Oil separator

T6A

Plate heat exchanger inlet temperature sensor

6

Four-way valve

T6B

Plate heat exchanger outlet temperature sensor

7

Heat exchanger

T7C1

Compressor A discharge temperature sensor

8

Electronic expansion valve (EXV)

T7C2

Compressor B discharge temperature sensor

9

Low pressure switch

SV4

Oil return valve

10

Fan motor

SV5

Fast defrosting (in heating) and unloading (in cooling) valve

11

Fan

SV6

Refrigerant bypass EXV valve

12

Stop valve (liquid side)

SV7

Refrigerant bypass indoor units valve

13

Stop valve (gas side)

SV8A

Compressor A vapor injection valve

1

15

12

9

3

4

5

6

11

10

7

14

8

8

13

EXVA

EXVC

E

S

C

SV8A

SV4

SV7

SV5

SV6

T3

T4

T6B

T6A

2

T7C1

T7C2

14/16/18HP

Figure 2-2.2: 14/16/18HP piping diagram

17

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Legend

No.

Parts name

No.

Parts name

1

Compressor

15

Accumulator

2

Discharge temperature switch

T3

Heat exchanger temperature sensor

3

High pressure switch

T4

Outdoor ambient temperature sensor

4

High pressure sensor

T6A

Plate heat exchanger inlet temperature sensor

5

Oil separator

T6B

Plate heat exchanger outlet temperature sensor

6

Four-way valve

T7C1

Compressor A discharge temperature sensor

7

Heat exchanger

T7C2

Compressor B discharge temperature sensor

8

Electronic expansion valve (EXV)

SV4

Oil return valve

9

Low pressure switch

SV5

Fast defrosting (in heating) and unloading (in cooling) valve

10

Fan motor

SV6

Refrigerant bypass EXV valve

11

Fan

SV8A

Compressor A vapor injection valve

12

Stop valve (liquid side)

SV8B

Compressor B vapor injection valve

13

Stop valve (gas side)

SV9

Compressor B pressure balance valve

14

Plate heat exchanger

7

1

1

15

12

9

3

4

5

6

11

11

10 10

8

13

EXVA

E

S

C

SV9

SV4

SV5

SV6

SV2

T3

T4

2

T7C1

T7C2

2

20/22/24HP

Figure 2-2.3: 20/22/24HP piping diagram

18

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Part 2

- Component Layout

and

Refrigerant Circuits

Legend

No.

Parts name

No.

Parts name

1

Compressor

15

Accumulator

2

Discharge temperature switch

T3

Heat exchanger temperature sensor

3

High pressure switch

T4

Outdoor ambient temperature sensor

4

High pressure sensor

T6A

Plate heat exchanger inlet temperature sensor

5

Oil separator

T6B

Plate heat exchanger outlet temperature sensor

6

Four-way valve

T7C1

Compressor A discharge temperature sensor

7

Heat exchanger

T7C2

Compressor B discharge temperature sensor

8

Electronic expansion valve (EXV)

SV4

Oil return valve

9

Low pressure switch

SV5

Fast defrosting (in heating) and unloading (in cooling) valve

10

Fan motor

SV6

Refrigerant bypass EXV valve

11

Fan

SV8A

Compressor A vapor injection valve

12

Stop valve (liquid side)

SV8B

Compressor B vapor injection valve

13

Stop valve (gas side)

SV9

Compressor B pressure balance valve

14

Plate heat exchanger

7

1

1

15

15

12

9

3

4

5

6

11

10

11

10

14

8

8

SV6

13

EXVA

EXVC

S

E

C

SV8A

SV8B

SV4

SV9

SV5

T3

T4

T6B

T6A

T7C1

T7C2

2

2

26/28HP

Figure 2-2.4: 26/28HP piping diagram

19

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Legend

No.

Parts name

No.

Parts name

1

Compressor

15

Accumulator

2

Discharge temperature switch

T3

Heat exchanger temperature sensor

3

High pressure switch

T4

Outdoor ambient temperature sensor

4

High pressure sensor

T6A

Plate heat exchanger inlet temperature sensor

5

Oil separator

T6B

Plate heat exchanger outlet temperature sensor

6

Four-way valve

T7C1

Compressor A discharge temperature sensor

7

Heat exchanger

T7C2

Compressor B discharge temperature sensor

8

Electronic expansion valve (EXV)

SV4

Oil return valve

9

Low pressure switch

SV5

Fast defrosting (in heating) and unloading (in cooling) valve

10

Fan motor

SV6

Refrigerant bypass EXV valve

11

Fan

SV7

Refrigerant bypass indoor units valve

12

Stop valve (liquid side)

SV8A

Compressor A vapor injection valve

13

Stop valve (gas side)

SV8B

Compressor B vapor injection valve

14

Plate heat exchanger

SV9

Compressor B pressure balance valve

7

1

1

15

15

12

9

3

4

5

6

11

10

11

10

14

8

8

13

EXVA

EXVC

E

S

C

SV6

SV5

SV9

S

V7

S

V4

SV8A

SV8B

T3

T4

T6B

T6A

T7C1

T7C2

2

2

30/32HP

Figure 2-2.5: 30/32HP piping diagram

20

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Part 2

- Component Layout

and

Refrigerant Circuits

Key components:

1. Oil separator:

Separates oil from gas refrigerant pumped out of the compressor and quickly returns it to the compressor. Separation

efficiency is up to 99%.

2. Accumulator:

Stores liquid refrigerant and oil to protect compressor from liquid hammering.

3. Electronic expansion valve (EXV):

Controls refrigerant flow and reduces refrigerant pressure.

4. Four-way valve:

Controls refrigerant flow direction. Closed in cooling mode and open in heating mode. When closed, the heat

exchanger functions as a condenser; when open, the heat exchanger functions as an evaporator.

5. Solenoid valve SV4:

Returns oil to the compressor. Opens once the compressor has run for 200 seconds and closes 600 seconds later and

then opens for 3 minutes every 20 minutes.

6. Solenoid valve SV5:

Enables fast defrosting in heating mode and unloading in cooling mode. During defrosting operation, opens to

shorten the refrigerant flow cycle and quicken the defrosting process. In cooling mode, SV5 opens when outdoor

ambient temperature is above 40oC or compressor frequency is below 41Hz.

7. Solenoid valve SV6:

Allows refrigerant to bypass the expansion valves. Opens in cooling mode when discharge temperature exceeds the

limit. Closed in heating mode and standby.

8. Solenoid valve SV7:

Allows refrigerant to return directly to the compressor. Opens when indoor air temperature is close to the set

temperature to avoid frequent compressor on/off.

9. Solenoid valve SV8A / SV8B:

Allows refrigerant from plate heat exchanger inject directly to the compressor. SV8A opens when compressor A

startup and closes when compressor A stop. SV8B delays opening when compressor B startup and closes when

compressor B stop.

10. Solenoid valve SV9:

Balances compressor B pressure. Opens before compressor B startup and closed after compressor B running for 15

seconds. Opens after compressor B stops 10s and keep opening 60s.

11. High and low pressure switches:

Regulate system pressure. When system pressure rises above the upper limit or falls below the lower limit, the high or

low pressure switches turn off, stopping the compressor. After 10 minutes, the compressor restarts.

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Midea V6-i Series Service Manual

7

1

15

12

9

3

2

4

5

6

11

10

14

8

13

EXVA

EXVC

E

S

C

T3

T4

T6B

T7C1

T7C2

T6A

SV8A

SV4

SV5

SV6

Closed

Filter

Filter

Closed

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

Fan

on

Fan

off

Fan

on

Fan

on

7

1

15

12

9

3

2

4

5

6

11

10

14

8

13

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

EXVA

EXVC

E

S

C

T3

T4

T6B

T7C1

T7C2

T6A

SV8A

SV4

SV5

SV6

300 steps

Filter

Filter

300 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

3 Refrigerant Flow Diagrams

8/10/12HP

Cooling operation

Figure 2-3.1: 8/10/12HP refrigerant flow during cooling operation

Oil return operation in cooling mode

Figure 2-3.2: 8/10/12HP refrigerant flow during oil return operation in cooling mode

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Part 2

- Component Layout

and

Refrigerant Circuits

7

1

15

12

9

3

2

4

5

6

11

10

14

8

13

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

EXVA

EXVC

E

S

C

T3

T4

T6B

T7C1

T7C2

T6A

SV8A

SV4

SV5

SV6

480 steps

Filter

Filter

480 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

480 steps

Filter

Filter

480 steps

Filter

Filter

Fan

off

Fan

off

Fan

off

Fan

off

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

7

1

15

12

9

3

2

4

5

6

11

10

14

8

13

EXVA

EXVC

E

S

C

T3

T4

T6B

T7C1

T7C2

T6A

SV8A

SV4

SV5

SV6

Closed

Closed

Filter

Filter

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Normal control

Filter

Filter

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

Oil return operation in heating mode and defrosting operation

Figure 2-3.3: 8/10/12HP refrigerant flow during oil return operation in heating mode and during defrosting operation

Heating operation

Figure 2-3.4: 8/10/12HP refrigerant flow during heating operation

23

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

SV7

7

1

15

12

9

3

2

4

5

6

11

10

14

13

EXVC

E

S

C

T3

T4

T6B

T7C1

T7C2

T6A

SV8A

SV4

SV5

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

EXVA

8

SV6

Closed

Filter

Filter

Closed

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

SV7

EXVA

8

SV6

7

1

15

12

9

5

6

11

10

14

13

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

EXVC

E

S

C

T3

T4

T6B

T7C1

T7C2

T6A

SV8A

SV4

SV5

300 steps

Filter

Filter

300 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

14/16/18HP

Cooling operation

Figure 2-3.5: 14/16/18 refrigerant flow during cooling operation

Oil return operation in cooling mode

Figure 2-3.6: 14/16/18HP refrigerant flow during oil return operation in cooling mode

24

-i V6-i VRF 50/60Hz

Part 2

- Component Layout

and

Refrigerant Circuits

SV7

EXVA

8

SV6

7

1

15

12

9

3

2

4

5

6

11

10

14

13

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

EXVC

E

S

C

T3

T4

T6B

T7C1

T7C2

T6A

SV8A

SV4

SV5

480 steps

Filter

Filter

480 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

480 steps

Filter

Filter

480 steps

Filter

Filter

Fan

off

Fan

off

Fan

off

Fan

off

SV7

EXVA

8

SV6

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

7

1

15

12

9

3

2

4

5

6

11

10

14

13

EXVC

E

S

C

T3

T4

T6B

T7C1

T7C2

T6A

SV8A

SV4

SV5

Closed

Closed

Filter

Filter

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Normal control

Filter

Filter

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

Oil return operation in heating mode and defrosting operation

Figure 2-3.7: 14/16/18HP refrigerant flow during oil return operation in heating mode and during defrosting operation

Heating operation

Figure 2-3.8: 14/16/18HP refrigerant flow during heating operation

25

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

7

1

1

159

3

4

5

6

11

11

10 10

8

13

EXVA

E

S

C

T3

T4

2

T7C1

T7C2

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

Closed

Filter

Filter

Closed

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

12

SV2

300 steps

Filter

Filter

300 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

7

1

1

159

3

4

5

6

11

11

10 10

8

13

EXVA

E

S

C

T3

T4

2

T7C1

T7C2

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

12

SV2

20/22/24HP

Cooling operation

Figure 2-3.9: 20/22/24 refrigerant flow during cooling operation

Oil return operation in cooling mode

Figure 2-3.10: 20/22/24HP refrigerant flow during oil return operation in cooling mode

26

-i V6-i VRF 50/60Hz

Part 2

- Component Layout

and

Refrigerant Circuits

480 steps

Filter

Filter

480 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

480 steps

Filter

Filter

480 steps

Filter

Filter

Fan

off

Fan

off

Fan

off

Fan

off

7

1

1

159

3

4

5

6

11

11

10 10

8

13

EXVA

E

S

C

T3

T4

2

T7C1

T7C2

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

12

SV2

Closed

Closed

Filter

Filter

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Normal control

Filter

Filter

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

7

1

1

159

3

4

5

6

11

11

10 10

8

13

EXVA

E

S

C

T3

T4

2

T7C1

T7C2

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

12

SV2

Oil return operation in heating mode and defrosting operation

Figure 2-3.11: 20/22/24HP refrigerant flow during oil return operation in heating mode and during defrosting operation

Heating operation

Figure 2-3.12: 20/22/24HP refrigerant flow during heating operation

27

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

15

15

7

1

1

12

9

3

4

5

6

11

11

10 10

14

8

8

13

EXVA

EXVC

E

S

C

T3

T4

2

T7C1

T7C2

T6B

T6A

SV8A

SV8B

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

Closed

Filter

Filter

Closed

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

300 steps

Filter

Filter

300 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

15

15

7

1

1

12

9

3

4

5

6

11

11

10 10

14

8

8

13

EXVA

EXVC

E

S

C

T3

T4

2

T7C1

T7C2

T6B

T6A

SV8A

SV8B

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

26/28HP

Cooling operation

Figure 2-3.13: 26/28 refrigerant flow during cooling operation

Oil return operation in cooling mode

Figure 2-3.14: 26/28HP refrigerant flow during oil return operation in cooling mode

28

-i V6-i VRF 50/60Hz

Part 2

- Component Layout

and

Refrigerant Circuits

480 steps

Filter

Filter

480 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

480 steps

Filter

Filter

480 steps

Filter

Filter

Fan

off

Fan

off

Fan

off

Fan

off

15

15

7

1

1

12

9

3

4

5

6

11

11

10 10

14

8

8

13

EXVA

EXVC

E

S

C

T3

T4

2

T7C1

T7C2

T6B

T6A

SV8A

SV8B

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

Closed

Closed

Filter

Filter

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Normal control

Filter

Filter

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

15

15

7

1

1

12

9

3

4

5

6

11

11

10 10

14

8

8

13

EXVA

EXVC

E

S

C

T3

T4

2

T7C1

T7C2

T6B

T6A

SV8A

SV8B

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

Oil return operation in heating mode and defrosting operation

Figure 2-3.15: 26/28HP refrigerant flow during oil return operation in heating mode and during defrosting operation

Heating operation

Figure 2-3.16: 26/28HP refrigerant flow during heating operation

29

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

15

15

7

1

1

12

3

4

5

6

11

11

10 10

14

8

8

13

EXVA

EXVC

E

S

C

T3

T4

2

T7C1

T7C2

T6B

T6A

SV8A

SV8B

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

Closed

Filter

Filter

Closed

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

9

S

V7

300 steps

Filter

Filter

300 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Filter

Filter

Normal control

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

15

15

7

1

1

12

3

4

5

6

11

11

10 10

14

8

8

13

EXVA

EXVC

E

S

C

T3

T4

2

T7C1

T7C2

T6B

T6A

SV8A

SV8B

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

9

S

V7

30/32HP

Cooling operation

Figure 2-3.17: 30/32 refrigerant flow during cooling operation

Oil return operation in cooling mode

Figure 2-3.18: 30/32HP refrigerant flow during oil return operation in cooling mode

30

-i V6-i VRF 50/60Hz

Part 2

- Component Layout

and

Refrigerant Circuits

480 steps

Filter

Filter

480 steps

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

480 steps

Filter

Filter

480 steps

Filter

Filter

Fan

off

Fan

off

Fan

off

Fan

off

15

15

7

1

1

12

3

4

5

6

11

11

10 10

14

8

8

13

EXVA

EXVC

E

S

C

T3

T4

2

T7C1

T7C2

T6B

T6A

SV8A

SV8B

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas
High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

9

S

V7

Closed

Closed

Filter

Filter

Unit on

Thermostat off

Unit on

Thermostat on

Unit on

Thermostat on

Unit off

Filter

Indoor unit operation

Filter

Normal control

Normal control

Filter

Filter

Filter

Filter

Fan

on

Fan

off

Fan

on

Fan

on

15

15

7

1

1

12

3

4

5

6

11

11

10 10

14

8

8

13

EXVB

EXVC

E

S

C

T3

T4

2

T7C1

T7C2

T6B

T6A

SV8A

SV8B

SV9

SV4

SV5

SV6

2

High temperature, high pressure gas

High temperature, high pressure liquid
Medium temperature, medium pressure gas
Low temperature, low pressure

9

S

V7

Oil return operation in heating mode and defrosting operation

Figure 2-3.19: 30/32HP refrigerant flow during oil return operation in heating mode and during defrosting operation

Heating operation

Figure 2-3.20: 30/32HP refrigerant flow during heating operation

31

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

32

V6-i VRF 50/60Hz

Part 3

- Control

Part 3

Control

1 General Control Scheme Flowchart ...................................................... 34

2 Stop Operation .................................................................................... 35

3 Standby Control ................................................................................... 35

4 Startup Control .................................................................................... 36

5 Normal Operation Control ................................................................... 38

6 Protection Control ............................................................................... 43

7 Special Control ..................................................................................... 45

33

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Legend

Numbers in the top right-hand

corners of boxes indicate the

relevant section of text on the

following pages.

Conditions met

for oil return

Conditions met

for defrosting

Thermo on

Special control

 Outdoor unit duty cycling

 Oil return operation

 Defrosting operation

7

Stop operation

 A unit stops when the load demanded decreases

2

Standby control

 Crankcase heater control

3

Startup control

 Startup control for heating operation

4

Thermo on

Normal operation control

 Outdoor fan control

5

Protection control

Compressor and inverter module protection

 Disable heating control

6

1 General Control Scheme Flowchart

Sections 3-2 to 3-7 on the following pages detail when each of the controls in the flowchart below is activated.

 Abnormal shutdown
 System stops

 Compressor startup delay control
 Startup control for cooling operation

 Component control during normal operation

 Compressor output control
 Compressor step control
 Operation priority and rotation of compressors
 Electronic expansion valve control

 High pressure protection control

 Low pressure protection control

 Discharge temperature protection control


control

34

V6-i VRF 50/60Hz

Part 3

- Control

Figure 3-3.1: Crankcase heater controlled according to outdoor ambient temperature

Figure 3-3.2: Crankcase heater controlled according to discharge temperature

Ambient temperature < 35 oC

Ambient temperature > 40 oC

Crankcase heater off

Crankcase heater is controlled according to discharge temperature

Discharge temperature < 40 oC

Discharge temperature > 50 oC

Crankcase heater off

Crankcase heater on

2 Stop Operation

The stop operation occurs for one of the three following reasons:

1. Abnormal shutdown: in order to protect the compressors, if an abnormal state occurs the system makes a 'stop with

thermo off' operation and an error code is displayed on the outdoor unit digital displays.

2. The system stops when the set temperature has been reached.

3 Standby Control

3.1 Crankcase Heater Control

The crankcase heater is used to prevent refrigerant from mixing with compressor oil when the compressors are stopped.

The crankcase heater is controlled according to outdoor ambient temperature and discharge temperature. When the

outdoor ambient temperature is above 40°C, the crankcase heater is off; when the outdoor ambient temperature is below

35°C, the crankcase heater is controlled according to discharge temperature. Refer to Figures 3-3.1 and 3-3.2.

35

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Component

Wiring

diagram

label

8-12HP

14-18HP

20-24HP

26-28HP

30-32HP

Control functions and states

Inverter compressor A

COMP(A)

● ● ● ● ●

Controlled according to load requirement,

operating frequency increased by 1 step / sec

Inverter compressor B

COMP(B)

● ● ●

DC fan motor A

FANA

● ● ● ● ●

Fan speed1 controlled according to discharge

pressure (Pc):

 At initial speed for 90 seconds.
 Subsequently, P

c

checked every 10

seconds:

 P

c

≥ 2.7MPa => 1 step increase.

 P

c

≤ 2.1MPa => 1 step decrease.

DC fan motor B

FANB

● ● ●

Electronic expansion

valve A

EXVA

● ● ● ● ●

Position (steps) from 0 (fully closed) to 480 or

3000 (fully open), controlled according to

discharge temperature

Electronic expansion

valve C

EXVC

● ● ● ● ●

Position (steps) from 0 (fully closed) to 480

(fully open), controlled according to

temperature different between plate heat

exchanger inlet and outlet

Four-way valve

ST1

● ● ● ● ●

Off

Solenoid valve (oil

balance)

SV4

● ● ● ● ●

Closed for 200 secs, open for 600 secs, then

closed

Solenoid valve (fast

defrosting (in cooling)

and unloading (in

heating))

SV5

● ● ● ● ●

Open for 4 mins, then closed
Solenoid valve (EXV

bypass)

SV6

● ● ● ● ●

Open for 10 mins, then controlled according

to pressure

Solenoid valve (indoor

units bypass)

SV7

●

●

Controlled according to load requirement

Solenoid valve

(inverter compressor A

vapor injection)

SV8A

● ● ● ●

Controlled according to inverter compressor

A

Solenoid valve

(inverter compressor B

vapor injection)

SV8B

● ●

Controlled according to inverter compressor

B

Solenoid valve

(inverter compressor B

pressure balance)

SV9

● ● ●

Open before compressor B startup

Notes:

1. Refer to Table 3-5.3 in Part 3, 5.6 “Outdoor Fan Control” for more information on fan speed steps.

4 Startup Control

4.1 Compressor Startup Delay Control

In initial startup control, compressor startup is delayed for 12 minutes in order to let the outdoor unit search for the indoor

units’ addresses. In restart control (except in oil return operation and defrosting operation), compressor startup is delayed

such that a minimum of 7 minutes has elapsed since the compressor stopped, in order to prevent frequent compressor

on/off and to equalize the pressure within the refrigerant system.

4.2 Startup Control for Cooling Operation

Table 3-4.1: Component control during startup in cooling mode

36

V6-i VRF 50/60Hz

Part 3

- Control

Component

Wiring

diagram

label

8-12HP

14-18HP

20-24HP

26-28HP

30-32HP

Control functions and states

Inverter compressor A

COMP(A)

● ● ● ● ●

Controlled according to load requirement,

operating frequency increased by 1 step /

sec

Inverter compressor B

COMP(B)

● ● ●

DC fan motor A

FANA

● ● ● ● ●

Open once the four-way valve has opened,

controlled according to outdoor ambient

temperature and load requirement

DC fan motor B

FANB

● ● ●

Electronic expansion

valve A

EXVA

● ● ● ● ●

Position (steps) from 0 (fully closed) to 480

or 3000 (fully open), controlled according

to discharge superheat

Electronic expansion

valve C

EXVC

● ● ● ● ●

Position (steps) from 0 (fully closed) to 480

(fully open), controlled according to

temperature different between plate heat

exchanger inlet and outlet

Four-way valve

ST1

● ● ● ● ●

On

Solenoid valve (oil

balance)

SV4

● ● ● ● ●

Closed for 200 secs, open for 600 secs, then

closed

Solenoid valve (fast

defrosting (in cooling)

and unloading (in

heating))

SV5

● ● ● ● ●

Open for 4 mins, then closed
Solenoid valve (EXV

bypass)

SV6

● ● ● ● ●

Off

Solenoid valve (indoor

units bypass)

SV7

●

●

Controlled according to load requirement

Solenoid valve (inverter

compressor A vapor

injection)

SV8A

● ● ● ●

Controlled according to inverter

compressor A

Solenoid valve (inverter

compressor B vapor

injection)

SV8B

● ●

Controlled according to inverter

compressor B

Solenoid valve (inverter

compressor B pressure

balance)

SV9

● ● ●

Open before compressor B startup

4.3 Startup Control for Heating Operation

Table 3-4.2: Component control during startup in heating mode

37

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Component

Wiring

diagram

label

8-12HP

14-18HP

20-24HP

26-28HP

30-32HP

Control functions and states

Inverter compressor A

COMP(A)

● ● ● ● ●

Controlled according to load requirement
Inverter compressor B

COMP(B)

● ● ●

DC fan motor A

FANA

● ● ● ● ●

Controlled according to discharge pressure
DC fan motor B

FANB

● ● ●

Electronic expansion

valve A

EXVA

● ● ● ● ●

Position (steps) from 0 (fully closed) to 480

or 3000 (fully open), controlled according to

discharge temperature

Electronic expansion

valve C

EXVC

● ● ● ● ●

Position (steps) from 0 (fully closed) to 480

(fully open), controlled according to

temperature different between plate heat

exchanger inlet and outlet

Four-way valve

ST1

● ● ● ● ●

On

Solenoid valve (oil

balance)

SV4

● ● ● ● ●

Open regularly

Solenoid valve (fast

defrosting (in cooling)

and unloading (in

heating))

SV5

● ● ● ● ●

Controlled according to ambient

temperature, discharge pressure, discharge

temperature, compressor running

frequency and discharge superheat

Solenoid valve (EXV

bypass)

SV6

● ● ● ● ●

Controlled according to discharge pressure

and discharge temperature

Solenoid valve (indoor

units bypass)

SV7

●

●

Controlled according to load requirement

Solenoid valve (inverter

compressor A vapor

injection)

SV8A

● ● ● ● ●

Controlled according to inverter compressor

A on/off

Solenoid valve (inverter

compressor B vapor

injection)

SV8B

● ●

Controlled according to inverter compressor

B on/off

Solenoid valve (inverter

compressor B pressure

balance)

SV9

● ● ●

Open before compressor B startup and close

after compressor B running for 15 seconds.

Open after compressor B stop 10 seconds

and keep open 60 seconds.

5 Normal Operation Control

5.1 Component Control during Normal Operation

Table 3-5.1: Component control during normal cooling operation

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Component

Wiring

diagram

label

8-12HP

14-18HP

20-24HP

26-28HP

30-32HP

Control functions and states

Inverter compressor A

COMP(A)

● ● ● ● ●

Controlled according to load requirement
Inverter compressor B

COMP(B)

● ● ●

DC fan motor A

FANA

● ● ● ● ●

Controlled according to outdoor ambient

temperature, outdoor heat exchanger pipe

temperature, discharge pressure and load

requirement

DC fan motor B

FANB

● ● ●

Electronic expansion

valve A

EXVA

● ● ● ● ●

Position (steps) from 0 (fully closed) to 480

or 3000 (fully open), controlled according to

discharge superheat

Electronic expansion

valve C

EXVC

● ● ● ● ●

Position (steps) from 0 (fully closed) to 480

(fully open), controlled according to

temperature different between plate heat

exchanger inlet and outlet

Four-way valve

ST1

● ● ● ● ●

On

Solenoid valve (oil

balance)

SV4

● ● ● ● ●

Open regularly

Solenoid valve (fast

defrosting (in cooling)

and unloading (in

heating))

SV5

● ● ● ● ●

Controlled according to ambient

temperature, discharge pressure, discharge

temperature, compressor running

frequency and discharge superheat

Solenoid valve (EXV

bypass)

SV6

● ● ● ● ●

Off

Solenoid valve (indoor

units bypass)

SV7

●

●

Controlled according to load requirement

Solenoid valve (inverter

compressor A vapor

injection)

SV8A

● ● ● ●

Controlled according to inverter compressor

A on/off

Solenoid valve (inverter

compressor B vapor

injection)

SV8B

● ●

Controlled according to inverter compressor

B on/off

Solenoid valve (inverter

compressor B pressure

balance)

SV9

● ● ●

Open before compressor B startup and close

after compressor B running for 15 seconds.

Open after compressor B stop 10 seconds

and keep open 60 seconds.

Table 3-5.2: Component control during heating operation

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Figure 3-5.1: Compressor priority and rotation – one outdoor unit

BP

No. 1

BP1

No. 1 No. 2

BP2

5.2 Compressor Output Control

The compressor rotation speed is controlled according to the load requirement. Before compressor startup, the outdoor

unit first estimates the indoor unit load requirement according to the nominal capacity of indoor units currently running,

and then correct for ambient temperature. The compressors then start up according to the corrected load requirement.

During operation the compressors are controlled according to the nominal capacity of indoor units currently running and

the indoor unit heat exchanger temperatures.

5.3 Compressor Step Control

The running speed of the compressors in rotations per second (rps) is one third of the frequency (in Hz) of the electrical

input to the compressor motors. The compressor speed can be altered in increments of 1 rps.

5.4 Operating Priority and Rotation of Compressors

Figures 3-5.1 shows the compressor operating priority and rotation in the outdoor unit. In units with two compressors,

inverter compressor A (BP1) operates in priority to inverter compressor B (BP2).

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Fan speed index

Fan speed (rpm)

8-18HP

20-22HP

24-32HP

FANA / FANB

FANA / FANB

0 0 0 / 0

0 / 0

1

120

150 / 0

120 / 0

2

150

190 / 0

150 / 0

3

170

230 / 0

170 / 0

4

190

270 / 0

190 / 0

5

210

310 / 0 (150 / 150)

210 / 0

6

230

350 / 0 (180 / 180)

230 / 0

7

250

380 / 0 (210 / 210)

250 / 0 (120 / 120)

8

270

410 / 0 (240 / 240)

270 / 0 ( 150 / 150)

9

290

280 / 280

330 / 0 (170 / 170)

10

310

320 / 320

370 / 0 (190 / 190)

11

330

360 / 360

210 / 210

12

350

400 / 400

230 / 230

13

370

440 / 440

250 / 250

14

390

480 / 480

270 / 270

15

410

520 / 520

290 / 290

16

430

560 / 560

310 / 310

17

450

600 / 600

330 / 330

18

470

640 / 640

350 / 350

19

490

680 / 680

370 / 370

20

510

720 / 720

400 / 400

21

530

760 / 760

430 / 430

22

560

800 / 800

470 / 470

5.5 Electronic Expansion Valve Control

EXVA control

The position of electronic expansion valves EXVA is controlled in steps from 0 (fully closed) to 480 (fully open) or 3000

(fully open).

In cooling mode:

 When the outdoor unit is in standby:

 EXVA is at position 352 (steps) or 2112 (steps).

 When the outdoor unit is running:

 EXVA is controlled according to discharge temperature.

In heating mode:

 When the outdoor unit is in standby:

 EXVA is at position 352 (steps) or 2112 (steps).

 When the outdoor unit is running:

 EXVA is controlled according to discharge superheat.

EXVC control

The positions of electronic expansion valves EXVC are controlled in steps from 0 (fully closed) to 480 (fully open).

In cooling / heating mode:

 When the outdoor unit is in standby:

 EXVC is fully closed.

 When the outdoor unit is running:

 EXVC is controlled according to temperature different between plate heat exchanger inlet and outlet.

5.6 Outdoor Fan Control

The speed of the outdoor unit fans is adjusted in steps, as shown in Table 3-5.3.

Table 3-5.3: Outdoor fan speed steps

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23

580

840 / 840

510 / 510

24

600

880 / 880

550 / 550

25

630

910 / 910

600 / 600

26

650

940 / 940

650 / 650

27

700

980 / 980

700 / 700

28

750

1010 / 1010

750 / 750

29

800

1020 / 1020

800 / 800

30

850

1050 / 1050

830 / 830

31

880

1080 / 1080

850 / 850

32

920

1120 / 1120

870 / 870

33

920

1140 / 1140

890 / 890

34

920

1140 / 1140

920 / 920

35

920

1140 / 1140

920 / 920

36 (ESP 40Pa mode)

950

1200 / 1200

950 / 950

37 (ESP 60Pa mode)

980

1200 / 1200

980 / 980

Note:

1. For 20-22HP unit fan speed 5 to 8 and 24-32HP unit fan speed 7 to 10, when fan speed decreases, the fan speed is shown in the bracket; when fan speed

increases, the fan speed is shown without bracket.

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Figure 3-6.1: High pressure protection control

Notes:

1. P

c

: Discharge pressure

Figure 3-6.2: Low pressure protection control

Notes:

1. P

e

: Suction pressure

Figure 3-6.3: Discharge temperature protection control

When P2 protection occurs 3 times

in 60 minutes, the H5 error is

displayed. When an H5 error occurs,

a manual system restart is required

before the system can resume

operation.

Pc > 4.4MPa

Pc < 3.2MPa

Normal operation

High pressure protection, error code P1 is displayed

Pe < 0.05MPa

Pe > 0.15MPa

Normal operation

Low pressure protection, error code P2 is displayed

120oC

100oC

90oC

Discharge temperature

Compressor off

90oC

6 Protection Control

6.1 High Pressure Protection Control

This control protects the system from abnormally high pressure and protects the compressors from transient spikes in

pressure.

6.2 Low Pressure Protection Control

This control protects the system from abnormally low pressure and protects the compressors from transient drops in

pressure.

6.3 Discharge Temperature Protection Control

This control protects the compressors from abnormally high temperatures and transient spikes in temperature. It is

performed for each compressor.

When the discharge temperature rises above 120°C the system displays P4 protection and all units stop running. When P4

protection occurs 3 times in 100 minutes, the H6 error is displayed. When an H6 error occurs, a manual system restart is

required before the system can resume operation.

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Figure 3-6.4: Compressor current protection control

Compressor model

AA55PHDG –D1YG

DC80PHDG –D1YG

Current

max

24.6

33

Figure 3-6.5: Inverter module temperature protection control

Notes:

1. T

f

: Heat sink temperature

Figure 3-6.6: Disable heating control

When PL protection occurs 3 times

in 100 minutes, the C7 error is

displayed. When a C7 error occurs, a

manual system restart is required

before the system can resume

operation.

Current ≥ Current

max

Current < Current

max

Normal operation

Compressor current protection, error code xP3 is displayed

Tf > 75oC

Tf < 73oC

Normal operation

Compressor output reduced

Tf > 80oC

Tf < 65oC

Inverter module temperature protection,

error code PL is displayed

Outdoor ambient temperature > 25oC

Outdoor ambient temperature < 23oC

Heating operation

Units stop

6.4 Compressor and Inverter Module Protection Control

This control protects the compressors from abnormally high currents and protects the inverter modules from abnormally

high temperatures. It is performed for each compressor and inverter module.

6.5 Disable Heating Control

When the outdoor ambient temperature rises above 25°C heating mode is disabled to prevent the mechanical load on

compressors becoming too high and to prevent low compression ratios which can result in insufficient compressor internal

oil lubrication.

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Table 3-7.1: Outdoor unit component control during oil return operation in cooling mode

Component

Wiring

diagram label

8-12HP

14-18HP

20-24HP

26-28HP

30-32HP

Control functions and states

Inverter compressor A

COMP(A)

● ● ● ● ●

Fixed frequency
Inverter compressor B

COMP(B)

● ● ●

DC fan motor A

FANA

● ● ● ● ●

Fan speed controlled according

to discharge pressure

DC fan motor B

FANB

● ● ●

Electronic expansion valve A

EXVA

● ● ● ● ●

Position 480 (steps) or 3000

(steps)

Electronic expansion valve C

EXVC

● ● ● ● ●

Position 96 (steps)

Four-way valve

ST1

● ● ● ● ●

Off

Solenoid valve (oil balance)

SV4

● ● ● ● ●

Normal control

Solenoid valve (fast defrosting)

SV5

● ● ● ● ●

On

Solenoid valve (EXV bypass)

SV6

● ● ● ● ●

On

Solenoid valve (indoor units

bypass)

SV7

●

●

Normal control

Solenoid valve (inverter

compressor A vapor injection)

SV8A

● ● ● ●

Controlled according to inverter

compressor A

Solenoid valve (inverter

compressor B vapor injection)

SV8B

● ●

Controlled according to inverter

compressor B

Solenoid valve (inverter

compressor B pressure balance)

SV9

● ● ●

Open before compressor B

startup

Table 3-7.2: Indoor unit component control during oil return operation in cooling mode

Component

Unit state

Control functions and states

Fan

Thermo on

Remote controller setting

Standby

Off

Thermo off

Off

Electronic expansion valve

Thermo on

Normal control

Standby

300 (steps)

Thermo off

300 (steps)

7 Special Control

7.1 Oil Return Operation

In order to prevent compressors from running out of oil, the oil return operation is conducted to recover oil that has

flowed out of the compressor(s) and into the piping system. This operation is performed for all units including units that

are in standby. When the outdoor unit is running in oil return, the digital display on outdoor main PCB will display “d0”.

Timing of oil return operation:

 When the initial cumulative operating time reaches 140 minutes and then every 8 hours.

Tables 3-7.1 and 3-7.2 show component control during oil return operation in cooling mode.

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Table 3-7.3: Outdoor unit component control during oil return operation in heating mode

Component

Wiring

diagram label

8-12HP

14-18HP

20-24HP

26-28HP

30-32HP

Control functions and states

Inverter compressor A

COMP(A)

● ● ● ● ●

Fixed frequency
Inverter compressor B

COMP(B)

● ● ●

DC fan motor A

FANA

● ● ● ● ●

Fan speed controlled according

to discharge pressure

DC fan motor B

FANB

● ● ●

Electronic expansion valve A

EXVA

● ● ● ● ●

Position 480 (steps) or 3000

(steps)

Electronic expansion valve C

EXVC

● ● ● ● ●

Position 96 (steps)

Four-way valve

ST1

● ● ● ● ●

Off

Solenoid valve (oil balance)

SV4

● ● ● ● ●

Normal control

Solenoid valve (fast defrosting)

SV5

● ● ● ● ●

On

Solenoid valve (EXV bypass)

SV6

● ● ● ● ●

On

Solenoid valve (indoor units

bypass)

SV7

●

●

Normal control

Solenoid valve (inverter

compressor A vapor injection)

SV8A

● ● ● ●

Off

Solenoid valve (inverter

compressor B vapor injection)

SV8B

● ●

Off

Solenoid valve (inverter

compressor B pressure balance)

SV9

● ● ●

Open before compressor B

startup

Table 3-7.4: Indoor unit component control during oil return operation in heating mode

Component

Unit state

Control functions and states

Fan

Thermo on

Off

Standby

Off

Thermo off

Off

Electronic expansion valve

Thermo on

480 (steps)

Standby

480 (steps)

Thermo off

480 (steps)

Tables 3-7.3 and 3-7.4 show component control during oil return operation in heating mode.

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Table 3-7.5: Outdoor unit component control during defrosting operation

Component

Wiring

diagram label

8-12HP

14-18HP

20-24HP

26-28HP

30-32HP

Control functions and states

Inverter compressor A

COMP(A)

● ● ● ● ●

Fixed frequency
Inverter compressor B

COMP(B)

● ● ●

DC fan motor A

FANA

● ● ● ● ●

Off
DC fan motor B

FANB

● ● ●

Electronic expansion valve A

EXVA

● ● ● ● ●

Position 480 (steps) or 3000

(steps)

Electronic expansion valve C

EXVC

● ● ● ● ●

Position 480 (steps)

Four-way valve

ST1

● ● ● ● ●

Off

Solenoid valve (oil balance)

SV4

● ● ● ● ●

Normal control

Solenoid valve (fast defrosting)

SV5

● ● ● ● ●

On

Solenoid valve (EXV bypass)

SV6

● ● ● ● ●

On

Solenoid valve (indoor units

bypass)

SV7

●

●

Normal control

Solenoid valve (inverter

compressor A vapor injection)

SV8A

● ● ● ●

Off

Solenoid valve (inverter

compressor B vapor injection)

SV8B

● ●

Off

Solenoid valve (inverter

compressor B pressure balance)

SV9

● ● ●

Open before compressor B

startup

Table 3-7.6: Indoor unit component control during defrosting operation

Component

Unit state

Control functions and states

Fan

Thermo on

Off

Standby

Off

Thermo off

Off

Electronic expansion valve

Thermo on

480 (steps)

Standby

480 (steps)

Thermo off

480 (steps)

7.2 Defrosting Operation

In order to recover heating capacity, the defrosting operation is conducted when the outdoor unit heat exchanger is

performing as an evaporator. The defrosting operation is controlled according to outdoor ambient temperature, outdoor

heat exchanger temperature, indoor heat exchanger temperature and outdoor unit running time. When the outdoor unit is

running in defrosting, the digital display on outdoor main PCB will display “df”.

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- Field Settings

Part 4

Field Settings

1 Outdoor Unit Field Settings ................................................................. 50

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Switch

Setting

Switch positions1

Description

S4

Static pressure

Standard static pressure (default)

Low static pressure mode (reserved)

Medium static pressure mode (reserved)

High static pressure mode (reserved)

Super high static pressure mode (reserved)

S5

Priority mode2

Auto priority (default)

Cooling priority

VIP priority or voting priority

Heating only

Cooling only

Set priority mode via centralized controller (reserved)

S6-1

Reserved

Reserved

S6-2

Clear indoor

unit addresses

No action (default)

Clear indoor unit addresses

Table continued on next page …

1 Outdoor Unit Field Settings

1.1 PCB Switches and Switch Settings

Figure 4-1.1: Outdoor unit main PCB switches

Table 4-1.1: Outdoor unit main PCB switch settings

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Switch

Setting

Switch positions1

Description

S6-3

Addressing

mode

Auto addressing (default)

Manual addressing

S8-1

Reserved

Reserved

S8-2

Start-up time

Start-up time is 12 minutes (default)

Start-up time is 7 minutes

S8-3

Reserved

Reserved

S7

Reserved

Reserved

S9

Reserved

Reserved

S13

Controller type

Use the new centralized controller (default)

Use the old centralized controller
ENC2

Outdoor unit

capacity3

Only 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C should be selected
0: 8HP; 1: 10HP; 2: 12HP; 3: 14HP; 4: 16HP; 5: 18HP; 6: 20HP; 7: 22HP; 8: 24HP;
9: 26HP; A: 28HP; B:30HP; C:32HP

ENC4

Network

address

Only 0, 1, 2, 3, 4, 5, 6, 7 should be selected (default is 0)

ENC3 S12

Number of

indoor units

The number of indoor units is in the range 0-15
0-9 on ENC3 indicate 0-9 indoor units; A-F on ENC3 indicate 10-15 indoor units

The number of indoor units is in the range 16-31
0-9 on ENC3 indicate 16-25 indoor units; A-F on ENC3 indicate 26-31 indoor units

The number of indoor units is in the range 32-47
0-9 on ENC3 indicate 32-41 indoor units; A-F on ENC3 indicate 42-47 indoor units

The number of indoor units is in the range 48-63
0-9 on ENC3 indicate 48-57 indoor units; A-F on ENC3 indicate 58-63 indoor units

ENC4

Silent mode4

0

Night silent time is 6h/10h (default)

1

Night silent time is 6h/12h

2

Night silent time is 8h/10h

3

Night silent time is 8h/12h

4

No silent mode

5

Silent mode 1 (only limit max. fan speed)

6

Silent mode 2 (only limit max. fan speed)

7

Silent mode 3 (only limit max. fan speed)

8

Super silent mode 1 (limit max. fan speed and compressor frequency)

9

Super silent mode 2 (limit max. fan speed and compressor frequency)

A

Super silent mode 3 (limit max. fan speed and compressor frequency)

B

Super silent mode 4 (limit max. fan speed and compressor frequency)

F

Set silent mode via centralized controller (reserved)

Notes:

1. Black denotes the switch position.

2. Refer to Part 4, 1.2.1 “Priority mode setting”.

3. Switch ENC2 is factory-set and its setting should not be changed.

4. Refer to Part 4, 1.2.2 “Silent mode setting”.

Table 4-1.1: Outdoor unit main PCB switch settings (continued)

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Figure 4-1.2: Indoor unit digital displays and LED indicators

DEF./FAN LED

Digital display

18oC

13oC

Outdoor ambient temperature

Cooling priority

Heating priority

1.2 Modes Set on Main PCB

1.2.1 Priority mode setting

Priority mode can be set on the outdoor unit. When an indoor unit is in mode conflict with the outdoor unit the unit

displays the mode conflict error. If the indoor unit has a digital display, it will display error code E0; if the indoor unit

display board has LED indicators, the “DEF./FAN” LED will flash rapidly.

There are five priority mode options:

1. Auto priority mode (default): In auto priority mode, the outdoor unit will operate in heating priority mode or cooling

priority mode according to the outdoor ambient temperature.

a) When the outdoor ambient temperature is below 13

heating priority mode does not change until the outdoor ambient temperature is above 18oC.

b) When the outdoor ambient temperature is above 18

cooling priority mode does not change until the outdoor ambient temperature is below 13oC.

c) When the outdoor unit restarts under the outdoor ambient between 13

same priority as before the last stop.

d) When the outdoor unit is initial startup under outdoor ambient temperature between 13

outdoor unit runs in heating priority mode.

Figure 4-1.3: Auto priority mode control

o

C, the outdoor units run in heating priority mode. The

o

C, the outdoor units run in cooling priority mode. The

o

C and 18oC, the outdoor unit runs the

o

C and 18oC, the

1.1. Heating priority mode:

a) During cooling operation: If an indoor unit requests heating, the outdoor unit stops and then restarts in heating

mode after 5 minutes. Indoor units requesting heating then start in heating mode and indoor units requesting

cooling display the mode conflict error.

b) During heating operation: If an indoor unit requests cooling, the outdoor unit ignores the request and continues

to run in heating mode. The indoor unit requesting cooling displays the mode conflict error. If all the indoor units

requesting heating are later turned off and one or more indoor units are still requesting cooling, the outdoor unit

restarts in cooling mode after 5 minutes and any indoor units requesting cooling then start in cooling mode.

1.2. Cooling priority mode:

a) During heating operation: If an indoor unit requests cooling, the outdoor unit stops and then restarts in cooling

mode after 5 minutes. Indoor units requesting cooling then start in cooling mode and indoor units requesting

heating display the mode conflict error.

b) During cooling operation: If an indoor unit requests heating, the outdoor units ignore the request and continue

to run in cooling mode. The indoor unit requesting heating displays the mode conflict error. If all the indoor units

requesting cooling are later turned off and one or more indoor units are still requesting heating, the outdoor unit

restarts in heating mode after 5 minutes and any indoor units requesting heating then start in heating mode.

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Table 4-1.2: Night silent time setting

Switch

Switch positions

Description

X

Y

ENC4

0

Night silent time is 6h/10h (default)

6

10 1 Night silent time is 6h/12h

6

12 2 Night silent time is 8h/10h

8

10 3 Night silent time is 8h/12h

8

12

Operation

sound dB

Load

Maximum

output

8:00

14:00

20:00

6:00

Night silent

mode activated

The outdoor unit senses the peak daytime
outdoor ambient temperature

6

10

Night silent mode

deactivated

Max. 15dB

reduction

2. Cooling priority mode: refer to above “1.2. Cooling priority mode” descriptions.

3. VIP priority mode or voting priority mode: The default VIP address is 63, and the VIP address also can be changed

through menu mode, refer to Part 5, 1.2.3 “Menu mode” Table 5-1.3 “nb8”. If the VIP indoor unit is operating, the

outdoor unit operates in the mode of the VIP indoor unit. Indoor units that are in a mode different to that of the VIP

unit display the mode conflict error. If there is no unit with VIP address or the VIP unit is in standby, the outdoor unit

operates in voting priority mode. In voting priority mode, the outdoor unit operates in whichever of heating and

cooling modes is being requested by the larger number of indoor units.

4. Heating only mode: The outdoor unit only operates in heating mode. Indoor units requesting heating operate in

heating mode. Indoor units requesting cooling or in fan only mode display the mode conflict error.

5. Cooling only mode: The outdoor unit only operates in cooling mode. Indoor units requesting cooling operate in

cooling mode; indoor units in fan only mode operate in fan only mode. Indoor units requesting heating display the

mode conflict error.

1.2.2 Silent time setting

1.2.2.1 Night silent time setting

Night silent mode is activated X hours after the peak daytime temperature, and is deactivated after Y hours, where X and Y

are as specified in Table 4-1.2.

Figure 4-1.2: Night silent mode example (default setting, 6h/10h)

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Table 4-1.3: Silent mode setting

Switch

Switch positions

Description

ENC4

5

Silent mode 1 (only limit max. fan speed)

6

Silent mode 2 (only limit max. fan speed)

7

Silent mode 3 (only limit max. fan speed)

8

Super silent mode 1 (limit max. fan speed and compressor frequency)

9

Super silent mode 2 (limit max. fan speed and compressor frequency)

A

Super silent mode 3 (limit max. fan speed and compressor frequency)

B

Super silent mode 4 (limit max. fan speed and compressor frequency)

Table 4-1.4: Maximum fan speed and capacity output control in different silent mode

ENC4

Switch positions

Description

Max. fan speed index1

Max.

capacity

output

8-10HP

12HP

14-18HP

20-22HP

24-26HP

28-32HP

8-32HP

0

Night silent time is 6h/10h (default)

28

28

28

22

28

28

100%

1

Night silent time is 6h/12h

2

Night silent time is 8h/10h

3

Night silent time is 8h/12h

4

No silent mode

30

31

30

30

30

31

5

Silent mode 1

28

28

28

27

28

28

6

Silent mode 2

26

26

26

25

26

26

7

Silent mode 3

24

24

24

23

24

24

8

Super silent mode 1

28

28

28

22

28

28

80%

9

Super silent mode 2

27

27

27

21

27

27

70%

A

Super silent mode 3

26

26

26

20

26

26

60%

B

Super silent mode 4

25

25

25

19

25

25

50%

Notes:

1. Fan speed (rpm) for different fan speed index refers to Table 3-5.3 in Part 3, 5.6 “Outdoor Fan Control”.

2. If the system pressure is over 3.5MPa, the system exits silent mode automatically.

1.2.2.2 Silent mode setting

In silent mode 1 / 2 / 3, the outdoor fan speed decreases gradually. In super silent mode 1 / 2 / 3 / 4 and night silent mode,

not only the fan speed decreases gradually, but also the compressor frequency decreases gradually.

1.2.2.3 Maximum fan speed and capacity output control in different silent mode

54

V6-i VRF 50/60Hz

Part 5

- Electrical Components and Wiring Diagrams

Part 5

Electrical Components and

Wiring Diagrams

1 Outdoor Unit Electric Control Box Layout ............................................. 56

2 Outdoor Unit Main PCB ....................................................................... 58

3 Compressor Inverter Module ............................................................... 65

4 Wiring Diagrams .................................................................................. 66

55

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Figure 5-1.1: 8-18HP top layer of electric control box

Figure 5-1.2: 8-18HP bottom layer of electric control box

Power supply
terminals

Communication

terminals block

Inductor

Filter boardMain PCB

Inverter
module Reactor

Pipe temp. sensor

Compressor connection wire

Fan module

Bridge rectifier

1 Outdoor Unit Electric Control Box Layout

8-18HP

56

V6-i VRF 50/60Hz

Part 5

- Electrical Components and Wiring Diagrams

Figure 5-1.3: 20-32HP top layer of electric control box

Figure 5-1.4: 20-32HP bottom layer of electric control box

Power supply
terminals

Communication
terminals block

Inductor

Inductor

Filter board

Main PCB

Inverter

module

Inverter

module

Reactor Reactor

Fan module

Fan module

Compressor

connection wiring

Compressor

connection wiring

Bridge rectifier

Bridge rectifier

20-32HP

57

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

2 Outdoor Unit Main PCB

2.1 Ports

Figure 5-2.1: Outdoor unit main PCB ports

1

Notes:

1. Label descriptions are given in Table 5-2.1.

58

V6-i VRF 50/60Hz

Part 5

- Electrical Components and Wiring Diagrams

Table 5-2.1: Main PCB ports

Label in

Figure 5-2.1

Port code

Content

Port voltage

1

CN18

Low pressure switch connection

0V or 5V DC

2

CN19

High pressure switch and discharge temperature switch(es)

connections

0V or 5V DC

3

CN4

Compressor top temperature sensor (single compressor

units) or compressor A compressor top temperature sensor

(dual compressor units) connection

0-5V DC (varying)

4

CN5

Discharge pipe temperature sensor (single compressor units)

or compressor B compressor top temperature sensor (dual

compressor units) connection

0-5V DC (varying)

5

CN3

Inverter module temperature sensor A connection

0-5V DC (varying)

6

CN3_1

Inverter module temperature sensor B connection

0-5V DC (varying)

7

CN17

High pressure sensor connection

0-5V DC (varying)

8

CN15

Inverter compressor A and B current sensor connections

0-7.8V AC (varying)

9

CN16

Reserved / 10

CN8

Plate heat exchanger inlet temperature sensor connection

0-5V DC (varying)

11

CN1

Outdoor ambient temperature sensor and outdoor heat

exchanger temperature sensor connections

0-5V DC (varying)

12

CN8_1

Plate heat exchanger outlet temperature sensor connection

0-5V DC (varying)

13

CN20

Communication port to outdoor unit

2.5-2.7V DC

14

CN26

Communication port to compressor drive board

2.5-2.7V DC

15

CN27

Communication port to fan drive board

2.5-2.7V DC

16

CN25

Communication port

2.5-2.7V DC

17

CN28

Reserved / 18

CN71

EEVB drive port

0V or 12V DC

19

CN70

EEVA drive port

0V or 12V DC

20

CN72

EEVC drive port

0V or 12V DC

21

CN82

Control port of relay for AC filter board

0V or 12V DC

22

CN66-CN67

Power supply to compressor crankcase heater

220V AC

23

CN47

Four-way valve drive ports

220V AC

24

CN41-CN46;

CN83-CN85

Solenoid valve drive ports

220V AC

25

CN30

Power input of main board

220V AC between A/B/C and N;

380V AC between A,B and C

59

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Table 5-2.2: Function of buttons SW3 to SW6

Button

Function

SW3 (UP)

In menu mode: previous and next buttons for menu

modes.

Not in menu mode: previous and next buttons for

system check information.

SW4 (DOWN)

SW5 (MENU)

Enter / exit menu mode.

SW6 (OK)

Confirm to enter specified menu mode.

2.2 Components

Layout 2.2.1

Figure 5-2.2: Outdoor unit main PCB components

Function of buttons SW3 to SW6 2.2.2

60

V6-i VRF 50/60Hz

Part 5

- Electrical Components and Wiring Diagrams

Start

Long press SW5 “MENU”

button for 5 seconds

Digital display displays “-n1”

Press SW3 / SW4 “UP /

the first level menu “nX”

Digital display displays “-nX”

Press SW6 “OK” button

level menu “-nX”

Digital display displays “-nX1”

Press SW3 / SW4 “UP /

second level menu “nXY”

Digital display displays “-nXY”

Press SW6 “OK” button to

menu “-nXY”

Confirm “-nXY”

Short press SW5

“MENU” button

Short press SW5

“MENU” button

Short press SW5

“MENU” button

Short press SW5

“MENU” button

Menu mode 2.2.3

1. Long press SW5 “MENU” button for 5 seconds to enter menu mode, and the digital display displays “n1”;

2. Press SW3 / SW4 “UP / DOWN” button to select the first level menu “n1”, “n2”, “n3”, “n4”or “nb”;

3. Press SW6 “OK” button to enter specified first level menu, for example, enter “n4” mode;

4. Press SW3 / SW4 “UP / DOWN” button to select the second level menu from “n41” to “n47”;

5. Press SW6 “OK” button to enter specified second level menu, for example, enter “n43” mode;

Menu mode selection flowchart:

DOWN” button to select

to enter specified first

DOWN” button to select the

enter specified second level

61

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

Digital display

content

Menu mode

Remarks

n14

Debug mode 1

All indoor units running in cooling mode

n15

Debug mode 2

If all indoor units in the system are the 2nd generation indoor units, all the indoor units

will run in heating mode. Once there is one or more old indoor unit in the system, all the

indoor units will run in forced cooling mode

n16

Maintenance mode

The system does not check the indoor units’ number.

n24

Reserved n25

Reserved

n26

Backup run

Only available for outdoor unit with two compressors. If one of the two compressors fails,

the other compressor will keep running for up to 4 days and then stop automatically.

n27

Vacuum mode

It is only used in maintenance process. The digital display displays “R006”, and all solenoid

valves are opened and EXVs are opened to the maximum steps.

n31

History error codes

n32

Cleaning history error codes

n33

Reserved n34

Factory reset n41

Power limitation mode 1

100% capacity output

n42

Power limitation mode 2

90% capacity output

n43

Power limitation mode 3

80% capacity output

n44

Power limitation mode 4

70% capacity output

n45

Power limitation mode 5

60% capacity output

n46

Power limitation mode 6

50% capacity output

n47

Power limitation mode 7

40% capacity output

nb1

Fahrenheit degree setting (oF)

nb2

Celsius degree setting (oC)

nb3

Exit auto power save mode

t

nb4

Enter auto power save mode

nb5

Auto snow-blowing mode 1 (customized)

According to outdoor ambient temperature (T4), the outdoor fan(s) periodically stop for

15 minutes and run for 2 minute

nb6

Auto snow-blowing mode 2 (customized)

According to outdoor ambient temperature (T4), the outdoor fan(s) periodically stop for

30 minutes and run for 2 minute

nb7

Exit auto snow-blowing mode

nb8

VIP address setting

The digital display will display “IdXX”, “XX” stands for VIP address, use UP / DOWN button

to change the VIP address and press OK button to confirm the specified VIP address.

nF1

Reserved nF2

Reserved

Menu mode function:

Table 5-2.3: Menu mode function

62

V6-i VRF 50/60Hz

Part 5

- Electrical Components and Wiring Diagrams

Menu mode

Manual exit method

Automatic exit method

System restart

Debug mode 1 (2)

Long press SW6 “OK” button when the digital

display is not in menu selection state

After running 120 minutes

Invalid

Maintenance mode

/

After running 60 minutes

Invalid

Backup run

/

After running 4 days or both

two compressors are failed

Invalid

Vacuum mode

Long press SW6 “OK” button when the digital

display is not in menu selection state

After running 8 hours

Invalid

Power limitation mode

Select power limitation mode 1 “n41”

/

Valid

Auto power save mode

Select “nb3”

/

Valid

Auto snow-blowing mode 1 (2)

Select “nb7”

/

Valid

VIP address setting

/

/

Valid

o

F / oC setting

/

/

Valid

DSP1

content

Parameters displayed on DSP2

Remarks

0.--

Unit address

For V6 Individual outdoor unit: 0

1.--

Unit capacity

Refer to Note 1

2.--

Number of outdoor units

For V6 Individual outdoor unit: 1

3.--

Number of indoor units as set on PCB

4.--

The capacity of outdoor unit

5.--

Total capacity requirement of indoor units

6.--

Total corrected capacity requirement of indoor units

7.--

Operating mode

Refer to Note 2

8.--

Outdoor unit actual operating capacity

9.--

Fan A speed index

Refer to Note 3

10.--

Fan B speed index

Refer to Note 3

11.--

Indoor heat exchanger pipe (T2/T2B) temperature (°C)

Actual value = value displayed

12.--

Main heat exchanger pipe (T3) temperature (°C)

Actual value = value displayed

13.--

Outdoor ambient (T4) temperature (°C)

Actual value = value displayed

14.--

Plate heat exchanger cooling refrigerant inlet (T6A) temperature (°C)

Actual value = value displayed

15.--

Plate heat exchanger cooling refrigerant outlet (T6B) temperature (°C)

Actual value = value displayed

16.--

Inverter compressor A discharge temperature (°C)

Actual value = value displayed

17.--

Inverter compressor B discharge temperature (°C)

Actual value = value displayed

18.--

Inverter module A heatsink temperature (°C)

Actual value = value displayed

19.--

Inverter module B heatsink temperature (°C)

Actual value = value displayed

20.--

Plate heat exchanger cooling refrigerant outlet temperature minus inlet temperature (°C)

Actual value = value displayed

21.--

Discharge superheat degree (°C)

Actual value = value displayed

22.--

Inverter compressor A current (A)

Actual value = value displayed

23.--

Inverter compressor B current (A)

Actual value = value displayed

24.--

EXVA position

Refer to Note 4

25.--

EXVB position

Refer to Note 4

26.--

EXVC position

Refer to Note 4

27.--

Compressor discharge pressure (MPa)

Actual value = value displayed × 0.1

28.--

Reserved 29.--

Number of indoor units currently in communication with the outdoor unit

Actual value = value displayed

30.--

Number of indoor units currently operating

31.--

Priority mode

Refer to Note 5

32.--

Silent mode

Refer to Note 6

33.--

Static pressure mode

Refer to Note 7

How to exit specified menu mode:

Table 5-2.4: Exit specified menu mode method:

UP / DOWN system check button 2.2.4

Before pressing UP or DOWN button, allow the system to operate steadily for more than an hour. On pressing UP or DOWN

button, the parameters listed in Table 5-2.5 will be displayed in sequence.

Table 5-2.5: System check

Table continued on next page …

63

V6-i VRF 50/60Hz

Midea V6-i Series Service Manual

DSP1

content

Parameters displayed on DSP2

Remarks

34.--

Reserved

35.--

Reserved

36.--

DC voltage A

Actual value = value displayed × 10

37.--

DC voltage B

Actual value = value displayed × 10

38.--

Reserved 39.--

Address of VIP indoor unit

40.--

Reserved

41.--

Reserved

42.--

Refrigerant quantity

Refer to Note 8

43.--

Reserved

44.--

Power mode

Refer to Note 9

45.--

Most recent error or protection code

“--“ is displayed if no error or protection events
have occurred since start-up

-- --

--

End

Table 5-2.6: Digital display output in different operating states

Outdoor unit state

Parameters displayed on DSP1

Parameters displayed on DSP2

Standby

Unit's address

The number of indoor units in

communication with the outdoor unit

Normal

operation

For single

compressor units

--

Running speed of the compressor in

rotations per second

For dual

compressor units

Running speed of compressor B in

rotations per second

Running speed of compressor A in

rotations per second

Error or protection

-- or placeholder

Error or protection code

In menu mode

Refer to Table 5-2.3

Refer to Table 5-2.3

System check

Refer to Table 5-2.5

Refer to Table 5-2.5

DSP1

DSP2

Table 5-2.5: System check (continued)

Notes:

1. Outdoor unit capacity setting:

 0: 8HP; 1: 10HP; 2: 12HP; 3: 14HP; 4: 16HP; 5: 18HP; 6: 20HP; 7: 22HP; 8: 24HP; 9: 26HP; A: 28HP; B: 30HP; C: 32HP.

2. Operating mode:

 0: off; 2: cooling; 3: heating; 4: forced cooling.

3. The fan speed index is related to the fan speed in rpm and can take any integer value in the range 1 (slowest) to 35 (fastest).

4. 480P: steps = value displayed × 4; 3000P: steps = value displayed × 24.

5. Priority mode:

 0: auto priority; 1: cooling priority; 2: VIP priority or voting priority; 3: heating only; 4: cooling only.

6. Silent mode:

 0: night silent time 6h/10h; 1: night silent time 6h/12h; 2: night silent time 8h/10h; 3: night silent time 8h/12h; 4: no silent mode; 5: silent mode 1; 6:

7. Static pressure mode:

8. Refrigerant quantity:

9. Power mode:

silent mode 2; 7: silent mode 3; 8: super silent mode 1; 9: super silent mode 2; 10: super silent mode 3; 11: super silent mode 4.

 0: standard static pressure; 1: low static pressure; 2: medium static pressure; 3: high static pressure; 4: super high static pressure.
 0: normal; 1: slightly excessive; 2: significantly excessive; 3: slightly insufficient; 4: significantly insufficient; 5: critically insufficient.
 0: 100% capacity output; 1: 90% capacity output; 2: 80% capacity output; 3: 70% capacity output; 4: 60% capacity output; 5: 50% capacity output; 6:

40% capacity output; 10: auto power save mode, 100% capacity output; 11: auto power save mode, 90% capacity output; 12: auto power save
mode, 80% capacity output; 13: auto power save mode, 70% capacity output; 14: auto power save mode, 60% capacity output; 15: auto power save
mode, 50% capacity output; 16: auto power save mode, 40% capacity output;

Digital display output 2.2.5

64

V6-i VRF 50/60Hz

Part 5

- Electrical Components and Wiring Diagrams

Table 5-3.1: LED indicators LED1 and LED2

Indicator

LED indicator function and status

LED 1

Inverter module operating indicator. Continuously on if the compressor is running normally and

flashing if an inverter module error has occurred1.

LED 2

Inverter module error indicator. Continuously on if an inverter module error has occurred1.

S7 on inverter module

Inverter module address

0 for compressor inverter module A

1 for compressor inverter module B

3 Compressor Inverter Module

Layout 3.1.1

Figure 5-3.1: Compressor inverter module components

LED indicators LED1 and LED2 3.1.2

Note:

1. If an inverter module error occurs, refer to Part 6, “Xh4 Troubleshooting”. The error code is displayed on the digital display.

Dial switch S7 setting 3.1.3

Dial switch S7 is used to set compressor inverter module A/B address. The compressor inverter module A/B location refers

to the wiring diagram.

65

V6

W

8

r

0

P

CN4

CN4

CN4

CN4

c

b

d

A

t

t

c

b

d

A

t

t

L3

L1’L2

L3

N

CN30

T

L3

L1

L2L3N

CN30

C

e

boa

d

DC fan drive

V

w

Ceboad

DC

fan

drive

XT1

T

erminal block

(

)
(

)

4

5

_

_

CN4

CN6

w

XT1Terminal

block

CN4

CN6

ENC1 is available in multi outdoor unit system

controller

cation

unication bus

ENC1

is

available

in

multi

outdoor

unit

system

controller

cation

unication

bus

‐iVRF5

4

iringDia

8‐2

HP

Figu

e5‐4.1:8‐28H

/60Hz

grams

wiringdiagra

XT1

AC filter

board

Main

board





m

5

18HP

4

A

28HP

16HP

3

2

1

0

ENC2

9

26HP

14HP

8

12HP

24HP

7

22HP

10HP

6

8HP

20HP

ENC2

capacity

setting

capacity

setting

ENC2

POWER

RA RB

DC fan drive

board B

DC fan drive

board A

BR1

BR2

DC Fan

High/Low pressure ON/OFF switch

Electronic expansion valv e

Crankcase heater

Inverter compressor A/B

Single-phase Bridge Rectifier

Current se nsor

High pressure s e ns or

Main exchanger pipe temperature

sensor

4-way valve

Reactance

Solenoid valve

Current se nsor

Outdoor ambie nt temperatur e se ns or

Plate heat exchanger cooling refrigerant

inlet/outlet temperature sensor

Discharge temperature ON/OFF switch

Discharge temperature sensor

Inverter-module heatsink temperature

sensor

Comm. board

CODE NAME

Up layer

Down layer

PCBA Layout

FAN A/B

EEVA/EEVB/EEVC

BR1/BR2

COMP A/COMP B

L8

H-PRO/L-PRO

HEATA/HEATB

ST1

H-YL1

IC17

T3

RA/RB

SV2/SV4-SV9

T4

T6A/T6B

TP1/TP2-PRO

T7C1/T7C2

TF1/TF2

Slave

12

Slave

Master

unit

ENC1 0

Outdoor unit

address

ENC1

.

；

unit 2

unit 1

do not change at will

，

(Factory

setting)

setting

ENC2 is factory setting

：

NUM_S

This connection diagram is for reference only.

Please refer to the actual product.

Attention

The dotted frame section is use by some m odels.

CN100

ENC2

POWER

ENC3

3
2

IN_NUM

1

S12

ENC1

NUM_S

ON

OKUPMENU DOWN

RB

Red(Black)

CN1

P_in

CN3

n

i

N_out

_

N

Red(Black)

P_out

CN10

L8

CN6

Red

White

e
u

MideaV6‐iSeriesServiceManual

l
B

RA

Red(Black)

CN1

P_in

CN3

n

i

N_out

_

N

Red(Black)

P_out

CN10

L8

CN6

Red

Red

U

V

w

e

u

l

Black

B

e core

Ferri

2
N
C

2
1

S7

ON

B

r
o

d

r

CN5

L1

CN5

L1

s

a

s

o

e

r

b

p

e

m

v

i

o

r

C

CN7

White

CN7

White

d

CN11

L3

L2

e
u

k

Bla

l
B

Red

U

V

w

e
u

l

Black

B

e core

Ferri

2
N

C

2
1

S7

ON

r

Black Blue

o

r

s

a

s

o

e

r
p

e

m

v

i

o

r
d

C

CN11

L3

L2

e

k

Blac

u

l
B

IC17

IC17

COMP B

Brown

CN8(CN9)

e
u

l
B

Black

V W

Red

CN12 CN 13 CN14

U

COMP A

CN8(CN9)

Black

e
u

l
B

Black

V W

Red

CN12 CN 13 CN14

U

L-PRO

CN19

H-PRO

CN18

DSP1 DSP2

H-YL1T7C1

T7C2

T6A

CN17

CN4

CN5 CN8

TF2

CN3

CN3_1

CN15

L-PRO

TF1

TF2

TP1-PRO

TP2-PRO

T7C2

H-YL1

T7C1

’

Black

CN12

’

’

CN11

’

CN10

Red White Blue

Red White Blue

CN9

e

u

l

(Right)

FAN B

FAN A

(Left)

B

-~

~

BR1

+

Red

N=1

CN3

Ferrite core

FAN A

Main board

O-D

6B

C

N8_1

T4 T3

O-O

CN1

CN20

T4

T3

T6A

T6B

CN51

CN50

r
r

filt
A

CN32(CN31)

CN31(CN32)

e

u

l
B

Black

~

Red

e

u

l
B

BR2

+

2 34

P

1

ON

SW1

N

board A

EE
CN7

CN28

0ACN72

O-FAN

O-C

CN27

CN26

CN25

EEVA

N

L3

L2

CN2 CN3 CN4

L1

CN1

+
P

­N

CN61

CN41

Black

-~

e

u

l
B

)

4

N

C

(

1

N

FAN B

C

EEVB
CN71

CN85

CN30

EEVC

N-ON
CN82

EEVC

EEVB

Black

e
u

l
B

White

Red

CN22 CN21

Yel lo

H-PRO

CN3

CN8

CN83

CN46

CN4

SV6 SV8BHEATB

CN44

CN43

CN41

SV2

CN47

ST1 SV4 SV5 SV7 SV8A SV9

CN67

1

CN67

HEATBHEATA

CN66

1

HEATA

CN66

Comm. board

Black

N

e
u

l
B

White

Black Black Black

Red

Black

ABC

SV8B

SV6

SV4 SV5 SV7 SV8A SV9

SV2

ST1

HEA TB

HEATB

HEATA

HEATA

To

outdoor

units comm-

To

indoor units

communi-

bus

To

centrali-

zed

To

kilowatt-

hour

meter

Reserved

Power in

XT1

Brown-1

Blue-1

Brown-2

Blue-2

2 34

P

1

ON

SW1

)

4

N

C

(

N

1

N

C

DC fan drive

board B



66





3

r

H

CN4

CN4

r

CN4

CN4

c

b

d

A

t

t

c

b

d

A

t

t

L3

L1

L2

L3

N

CN30

T

L3

L1

L2

L3

N

CN30

C

e

boa

d

DC fan drive

V

w

DC

fan

drive

(

)
(

)

4

5

_

_

CN4

CN6

w

V

ENC1 is available in multi outdoor unit system

CN4

CN6

controller

cation

unication bus

0

ENC1

is

available

in

multi

outdoor

unit

system

controller

cation

unication

bus

30‐

2HP

Figu

e5‐4.2:30‐32

Pwiringdiag

XT1

AC filter

board

Comm. board

Main

board

Up layer

am

RB RA

 V6‐i

RF50/6

Hz





.

；

Slave

C

32HP

DC fan drive

board B

DC fan drive

board A

BR1

BR2

30HP

DC Fan

Electronic expansion valve

Inverter compressor A/B

Single-phase Bridge Rectifier

High/Low press ur e O N/OFF switch

Crankcase heater

4-way valve

Reactance

Current sensor

High pressure sensor

Solenoid valve

Current sensor

Outdoor am bie nt temperatur e s en s or

Main exchanger pipe temperature

sensor

Plate heat exchanger coolin g refrigerant

inlet/outlet temperature sensor

CODE NAME

Down layer

PCBA Layout

FAN A/B

EEVA/EEVB/EEVC

BR1/BR2

H-PRO/L-PRO

HEATA/HEATB

COMP A/CO MP B

ST1

H-YL1

RA/RB

IC17

SV2/SV4-SV9

T3

L8

T4

T6A/T6B

Terminal block

Discharge temperature ON/OF F switch

Discharge temperature sensor

Inverter-module heatsink temperature

sensor

ENC2 B

capacity

setting

ENC2

T7C1/T7C2

TF1/TF2

XT1

TP1/TP2-PRO

POWER

unit 2

12

Slave

Master

unit

ENC1 0

Outdoor unit

ENC1

unit 1

do not change at will

，

(Factory

setting)

address

setting

ENC2 is factory setting

：

NUM_S

Attention

This connection diagram is for reference only.

Please refer to the actual product.

The dotted frame section is use by some m odels.

CN100

ENC2

POWER

ENC3

3
2

IN_NUM

1

S12

ENC1

NUM_S

ON

OKUPMENU DOWN

RB

Red(Black)

CN1

P_in

CN3

n

i

N_out

_

N

Red(Black)

P_out

CN10

L8

CN6

Red

White

e
u

l
B

RA

Red(Black)

CN1

P_in

CN3

n

i

N_out

_

N

Red(Black)

P_out

CN10

L8

CN6

Red

Red

U

V

w

e

u

l

Black

B

e core

Ferri

CN2

2
1

S7

ON

B

r
o

d

r

CN5

L1

CN5

L1

s

a

s

o

e

r

b

p

e

m

v

i

o

r

C

CN7

White

CN2

CN7

White

d

CN11

L3

L2

e

k

Bla

u

l
B

Red

U

V

w

e
u

l

Black

B

e core

Ferri

2
1

S7

ON

r

Black Blue

o

r

s

a

s

o

e

r
p

e

m

v

i

o

r
d

C

CN11

L3

L2

e
u

k

Blac

l
B

IC17

IC17

COMP B

Brown

CN8(CN9)

e
u

l
B

Black

V W

Red

CN12 CN 13 CN14

U

COMP A

CN8(CN9)

Black

e
u

l
B

Black

V W

Red

CN12 CN 13 CN14

U

L-PRO

CN19

H-PRO

CN4

L-PRO

TP1-PRO

TP2-PRO

’

Black

’

’

’

’

Red White Blue

Red White Blue

(Right)

FAN B

FAN A

(Left)

CN18

T7C2
CN5 CN8

TF2

CN3

CN3_1

TF1

T7C1

T7C2

CN12

CN11

CN10

CN9

Red

N=1

Ferrite core

DSP1 DSP2

H-YL1T7C1

T6A

CN17

CN15

TF2

H-YL1

e

u

l
B

-~

~

BR1

+

CN3

FAN A

Main board

6B

C

N8_1

T4 T3

CN1

T4

T3

T6A

T6B

CN50

r
r

filt
A

CN31(CN32)

Black

Red

e

u

l
B

P

N

O-D

EE
CN7

CN28

0ACN72

O-FAN

O-C

O-O

CN27

CN26

CN20

CN51

CN25

EEVA

N

L3

L2

CN2 CN3 CN4

L1

CN1

+
P

-

CN32(CN31)

e

u

l
B

Black

-~

~

BR2

+

2 34
1

ON

SW1

board A

N

CN61

CN41

e

u

l
B

)

4

N

C

(

1

N

FAN B

C

CN85

CN30

EEVC

EEVB

N-ON

CN71

CN82

EEVC

EEVB

Black

e
u

l
B

White

Red

CN22 CN21

Yell o

H-PRO

CN3

CN8

CN83

CN46

CN4

SV6 SV8BHEATB

CN44

CN43

CN41

SV2

CN47

ST1 SV4 SV5 SV7 SV8A SV9

CN67

1

CN67

HEATBHEATA

CN66

1

HEATA

CN66

Comm. board

Black

N

e
u

l
B

White

Black Black Black

Red

Black

Blue-1

Brown-2

Blue-2

P

N

DC fan drive

Brown-1

board B

ABC

XT1

XT1

2 34
1

ON

SW1

)

4

N

C

(

1

N

C

SV8B

SV6

SV4 SV5 SV7 SV8A SV9

SV2

ST1

HEA TB

HEATB

HEATA

HEATA

To

outdoor

units comm-

To

indoor units

communi-

bus

To

centrali-

zed

To

kilowatt-

hour

meter

Reserved

Part5‐ ElectricalComponentsandWiringDiagrams

Power in









67

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Midea V6-i Series Service Manual

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Part

6 - Diagnosis and Troubleshooting

Part 6

Diagnosis and

Troubleshooting

1 Error Code Table .................................................................................. 70

2 Troubleshooting .................................................................................. 71

3 Appendix to Part 6 ............................................................................. 125

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Error

code1

Content

Remarks

Manual re-start

required2

E1

Phase sequence error

Displayed on the unit with the error

Yes

E2

Communication error between indoor and outdoor units

Displayed on the unit with the error

No

E4

Outdoor heat exchanger temperature sensor (T3) error or

outdoor ambient temperature sensor (T4) error

Displayed on the unit with the error

No

E5

Abnormal power supply voltage

Displayed on the unit with the error

No

E7

Compressor top or discharge pipe temperature sensor (T7C1/2)

error

Displayed on the unit with the error

Yes

E8

Outdoor unit address error

Displayed on the unit with the error

Yes

xE9

EEPROM mismatch

Displayed on the unit with the error

Yes

xF1

DC bus voltage error

Displayed on the unit with the error

No

F3

Plate heat exchanger cooling refrigerant outlet temperature

sensor (T6B) error

Displayed on the unit with the error

No

F5

Plate heat exchanger cooling refrigerant inlet temperature sensor

(T6A) error

Displayed on the unit with the error

No

F6

Electronic expansion valve connection error

Displayed on the unit with the error

Refer to Note 3

Yes

xH0

Communication error between main control chip and inverter

driver chip

Displayed on the unit with the error

No

xH4

Inverter module protection

Displayed on the unit with the error

Yes

H5

P2 protection appears three times in 60 minutes

Displayed on the unit with the error

Yes

H6

P4 protection appears three times in 100 minutes

Displayed on the unit with the error

Yes

H7

Number of indoor units detected by outdoor unit not same as

number set on main PCB

Displayed on the unit with the error

No

H8

High pressure sensor error

Displayed on the unit with the error

No

H9

P9 protection appears ten times in 120 minutes

Displayed on the unit with the error

Yes

C7

PL protection appears three times in 100 minutes

Displayed on the unit with the error

Yes

P1

Discharge pipe high pressure protection

Displayed on the unit with the error

No

P2

Suction pipe low pressure protection

Displayed on the unit with the error

No

xP3

Compressor current protection

Displayed on the unit with the error

No

P4

Discharge temperature protection

Displayed on the unit with the error

No

P5

Outdoor heat exchanger temperature protection

Displayed on the unit with the error

No

P9

Fan module protection

Displayed on the unit with the error

No

1 Error Code Table

Table 6-1.1: Error code table

70

Table continued on next page …

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Part

6 - Diagnosis and Troubleshooting

Error

code1

Content

Remarks

Manual re-start

required2

PL

Inverter module temperature protection

Displayed on the unit with the error

No

PP

Compressor discharge insufficient superheat protection

Displayed on the unit with the error

No

xL0

Inverter module protection

Displayed on the unit with the error

Yes

xL1

DC bus low voltage protection

Displayed on the unit with the error

Yes

xL2

DC bus high voltage protection

Displayed on the unit with the error

Yes

xL4

MCE error

Displayed on the unit with the error

Yes

xL5

Zero speed protection

Displayed on the unit with the error

Yes

xL7

Phase sequence error

Displayed on the unit with the error

Yes

xL8

Compressor frequency variation greater than 15Hz within one

second protection

Displayed on the unit with the error

Yes

xL9

Actual compressor frequency differs from target frequency by

more than 15Hz protection

Displayed on the unit with the error

Yes

 All electrical work must be carried out by competent and suitably qualified, certified and

accredited professionals and in accordance with all applicable legislation (all national, local and other laws,

Power-off the outdoor units before connecting or disconnecting any connections or wiring, otherwise electric

shock (which can cause physical injury or death) may occur or damage to components may occur.

Warning

Table 6-1.1: Error code table (continued)

Notes:

1. 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1 representing compressor system A and 2

representing compressor system B. 'y' is a placeholder for the address (1 or 2) of the slave unit with the error.

2. For some error codes, a manual restart is required before the system can resume operation.

3. Once the EXV has been connected properly, the error code will flash to indicate that the connection has been re-established. A manual restart is then

required before the system can resume operation.

2 Troubleshooting

2.1 Warning

standards, codes, rules, regulations and other legislation that apply in a given situation).



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2.2 E1: Phase sequence error

Digital display output 2.2.1

Description 2.2.2

 Phase sequence error.
 All units stop running.
 Error code is displayed on the outdoor unit with the error.

Trigger / recover condition 2.2.3

 Trigger condition: Wrong phase connection for 1.6s or phase missing for 48s.
 Recover condition: Correct phase connection.
 Reset method: Manually restart.

Possible causes 2.2.4

 Power supply phases not connected in correct sequence.
 Power supply terminals loose.
 Power supply abnormal.
 Main PCB damaged.

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E1

The phase sequence of the 3-phase

power supply is incrorrect1

Yes

Exchange any two of the 3 phase wires

No

Some power supply terminals are loose2

Yes

Ensure all supply terminals are securely

fastened

No

The power supply is abnormal

Yes

Check the power supply equipment

No

Replace outdoor main PCB

Procedure 2.2.5

Notes:

1. The A, B, C terminals of the 3-phase power supply should match compressor phase sequence requirements. If the phase sequence is inverted, the

compressor will operate inversely. If the wiring connection of each outdoor unit is in A, B, C phase sequence, and multiple units are connected, the current
difference between C phase and A, B phases will be very large as the power supply load of each outdoor unit will be on C phase. This can easily lead to
tripped circuits and terminal wiring burnout. Therefore if multiple units are to be used, the phase sequence should be staggered, so that the current is
distributed among the three phases equally.

2. Loose power supply terminals can cause the compressors to operate abnormally and compressor current to be very large.

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2.3 E2: Communication error between indoor and outdoor unit

Digital display output 2.3.1

Description 2.3.2

 Communication error between indoor and outdoor unit.
 All units stop running.
 Error code is only displayed on the outdoor unit.

Trigger / recover condition 2.3.3

 Trigger condition: Indoor units and the outdoor unit cannot communicate for 2 minutes after the system is powered

on for 20 minutes.

 Recover condition: Communication go back to normal.
 Reset method: Resume automatically.

Possible causes 2.3.4

 Communication wires between indoor and outdoor units not connected properly.
 Indoor unit power supply abnormal.
 Loosened wiring within electric control box.
 Interference from high voltage wires or other sources of electromagnetic radiation.
 Communication wire too long.
 Damaged main PCB or electric control box communication terminals block.

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6 - Diagnosis and Troubleshooting

E2

Communication wires P Q E have short

circuited or disconnected1

Yes

Reconnect the communication wires

No

Communication wires P Q E are not

connected in a daisy chain

Yes

Connect the communication wires in a

daisy chain

No

IDU power supply is abnormal

Yes

Ensure normal power supply

No

Wires between outdoor main PCB and

electric control box communication

terminals block are loose

Yes

Ensure the wires are connected properly

No

Interference from high voltage (220V or

higher) wires

Yes

Ensure the communication wires and

high voltage wires are separated

No

Communication wires are close to a

source of electromagnetic radiation such

as transformer or strong fluorescent lamp

Yes

Remove the source of interference, or

add additional shielding to the

communication wires

No

The length of communication wire is over

1200m

Yes

Reduce the wire length to less than

1200m or strengthen the signal

No

Replacing outdoor main PCB resolves the

error

No

Replace electric control box

communication terminals block

Procedure 2.3.5

Notes:

1. Measure the resistance among P, Q and E. The normal resistance between P and Q is 120Ω, between P and E is infinite, between Q and E is infinite.

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2.4 E4: Temperature sensor (T3/T4) error

Digital display output 2.4.1

Description 2.4.2

 Outdoor heat exchanger temperature sensor (T3) error or outdoor ambient temperature sensor (T4) error.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.4.3

 Trigger condition: The main control board cannot receive the feedback signal of temperature sensor T3 or T4.
 Recover condition: The main control board can receive the feedback signal of temperature sensor T3 or T4.
 Reset method: Resume automatically.

Possible causes 2.4.4

 Temperature sensor not connected properly or has malfunctioned.
 Damaged main PCB.

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E4

Temperature sensor connection on main

PCB is loose1

Yes

Ensure the sensor is connected properly

No

Temperature sensor has short-circuited

or failed2

Yes

Replace the sensor

No

Replace outdoor main PCB

Procedure 2.4.5

Notes:

1. Outdoor ambient temperature sensor (T4) and heat exchanger temperature sensor (T3) connection is port CN1 on the main PCB (labeled 11 in Figure 5-2.1

in Part 5, 2.1 “Ports”).

2. Measure sensor resistance. If the resistance is too low, the sensor has short-circuited. If the resistance is not consistent with the sensor’s resistance

characteristics table, the sensor has failed. Refer to Table 6-3.1 in Part 6, 3.1 “Temperature Sensor Resistance Characteristics”.

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2.5 E5: Abnormal power supply voltage

Digital display output 2.5.1

Description 2.5.2

 Abnormal power supply voltage.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.5.3

 Trigger condition: Outdoor unit power supply phase voltage < 165V.
 Recover condition: Outdoor unit power supply phase voltage is > 180V.
 Reset method: Resume automatically.

Possible causes 2.5.4

 Outdoor unit power supply voltage is abnormal or a phase is missing.
 Loosened wiring within electric control box.
 High voltage circuit error.
 Main PCB damaged.

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Part

6 - Diagnosis and Troubleshooting

E5

ODU power supply is abnormal or a

phase is missing1

Yes

Provide normal power supply

No

Wires between outdoor main PCB, AC

filter boards and electric control box

power supply terminals are loose

Yes

Ensure the wires are connected properly

No

High voltage circuit error has occurred,

such as the compressor has

malfunctioned2, the fan motor has

short-circuited3, or the inverter module

has short-circuited4

Yes

Replace or repair the relevant parts

No

Replace outdoor main PCB

Figure 6-2.1: Inverter module terminals

Procedure 2.5.5

Notes:

1. The normal voltage between A and N, B and N, and C and N is 198-242V.

2. The normal resistances of the inverter compressor are 0.7-1.5Ω among U V W and infinite between each of U V W and ground. If any of the resistances

differ from these specifications, the compressor has malfunctioned.

3. The normal resistances of the fan motor coil among U V W are less than 10Ω. If a measured resistance is 0Ω, the fan motor has short-circuited.

4. Set a multi-meter to buzzer mode and test any two terminals of P N U V W of the inverter module. If the buzzer sounds, the inverter module has

short-circuited.

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2.6 E7: Temperature sensor (T7C1/2) error

Digital display output 2.6.1

Description 2.6.2

 A compressor top temperature sensor or discharge pipe temperature sensor (T7C1/2) error.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.6.3

 Trigger condition: Discharge pressure ≥ 3MPa and discharge temperature < 15
 Recover condition: Discharge pressure and temperature go back to normal.
 Reset method: Manually restart.

Possible causes 2.6.4

 Temperature sensor not connected properly or has malfunctioned.
 Damaged main PCB.

o

C for 2 minutes.

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Part

6 - Diagnosis and Troubleshooting

E7

Temperature sensor connection on main

PCB is loose1

Yes

Ensure the sensor is connected properly

No

Temperature sensor has short-circuited

or failed2

Yes

Replace the sensor

No

Replace outdoor main PCB

Procedure 2.6.5

Notes:

1. Compressor top temperature sensor and discharge pipe temperature sensor connections are ports CN4 and CN5 on the main PCB (labeled 3 and 4,

respectively, in Figure 5-2.1 in Part 5, 2.1 “Ports”).

2. Measure sensor resistance. If the resistance is too low, the sensor has short-circuited. If the resistance is not consistent with the sensor’s resistance

characteristics table, the sensor has failed. Refer to Table 6-3.2 in Part 6, 3.1 “Temperature Sensor Resistance Characteristics”.

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2.7 E8: Outdoor unit address error

Digital display output 2.7.1

Description 2.7.2

 Outdoor unit address error.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.7.3

 Trigger condition: Outdoor unit address is set more than 3.
 Recover condition: Outdoor unit addresses are set from 0 to 3.
 Reset method: Manually restart.

Possible causes 2.7.4

 Invalid outdoor unit address.
 Main PCB damaged.

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Part

6 - Diagnosis and Troubleshooting

E8

The ODU's address is not in the valid

range1

Yes

Slave units addresses should be set from

1 to 3

No

Replace the outdoor main PCB

Procedure 2.7.5

Notes:

1. The V6 Individual outdoor unit address should be set as 0.

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2.8 xE9: EEPROM mismatch

Digital display output 2.8.1

In the error code, 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1

representing compressor system A and 2 representing compressor system B.

Description 2.8.2

 1E9 indicates a compressor A EEPROM mismatch.
 2E9 indicates a compressor B EEPROM mismatch.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.8.3

 Trigger condition: Compressor drive parameter is mismatch.
 Recover condition: Compressor drive parameter is match.
 Reset method: Manually restart.

Possible causes 2.8.4

 Outdoor unit was powered on immediately after being powered off.
 Main PCB damaged.

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Part

6 - Diagnosis and Troubleshooting

xE9

The outdoor unit was powered on

immediately after being powered off1

Yes

Power off the unit and wait for the digital

display to turn off before restarting the

unit

No

Replace outdoor main PCB

Procedure 2.8.5

Notes:

1. When performing a manual restart of an outdoor unit, once the unit has been powered off it should not be powered on again until the digital display has

turned off.

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2.9 xF1: DC bus voltage error

Digital display output 2.9.1

'x' is a placeholder for the compressor system (compressor and related electrical components), with 1 representing

compressor system A and 2 representing compressor system B.

Description 2.9.2

 1F1 indicates compressor A DC bus voltage error; 2F1 indicates compressor B DC bus voltage error.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.9.3

 Trigger condition: DC bus voltage < 350V or DC bus voltage > 700V continuously for 10 seconds.
 Recover condition: DC bus voltage goes back to normal.
 Reset method: Restart automatically.

Possible causes 2.9.4

 Loosened wiring of the compressor inverter module.
 Incorrect wiring of the reactor and DC bus wire.
 Abnormal power supply.
 Inverter module damaged.

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Part

6 - Diagnosis and Troubleshooting

Figure 6-2.2: DC detection wire connection method

F1 error

Compressor inverter module wiring is

loosened

Reconnect cables based on

wiring diagram

Reactor and DC bus wiring is incorrectly

1

Reconnect the reactor and

DC bus wire based on wiring

diagram

The power supply is abnormal

No

No

Yes

Yes

Disconnect the
power supply

Check the power supply

equipment

Yes

Replace the inverter module

No

Procedure 2.9.5

Note:

1. The DC bus wire should run from the N_in terminal on the inverter module, through the current sensor (in the direction indicated by the

arrow on the current sensor), and end at the N_out terminal on the inverter module.

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2.10 F3, F5: Temperature sensor (T6B/T6A) error

Digital display output 2.10.1

Description 2.10.2

 F3 indicates plate heat exchanger cooling refrigerant outlet temperature sensor (T6B) error.
 F5 indicates plate heat exchanger cooling refrigerant inlet temperature sensor (T6A) error.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.10.3

 Trigger condition: Temperature sensor T6A(B) is open or short-circuit.
 Recover condition: Temperature sensor T6A(B) connection ports can detect load.
 Reset method: Resume automatically.

Possible causes 2.10.4

 Temperature sensor not connected properly or has malfunctioned.
 Damaged main PCB.

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F3 / F5

Temperature sensor connection on main

PCB is loose1

Yes

Ensure the sensor is connected properly

No

Temperature sensor has short-circuited

or failed2

Yes

Replace the sensor

No

Replace outdoor main PCB

Procedure 2.10.5

Notes:

1. Plate heat exchanger cooling refrigerant inlet temperature sensor (T6A) and plate heat exchanger cooling refrigerant outlet temperature sensor (T6B)

connection are port CN8 and CN8_1 on the main PCB (labeled 10 and 12, respectively, in Figure 5-2.1 in Part 5, 2.1 “Ports”).

2. Measure sensor resistance. If the resistance is too low, the sensor has short-circuited. If the resistance is not consistent with the sensor’s resistance

characteristics table, the sensor has failed. Refer to Table 6-3.1 in Part 6, 3.1 “Temperature Sensor Resistance Characteristics”.

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2.11 F6: Electronic expansion valve connection error

Digital display output 2.11.1

Description 2.11.2

 Electronic expansion valve connection error.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.11.3

 Trigger condition: The main control board cannot receive the feedback signal of EXV.
 Recover condition: The main control board can receive the feedback signal of EXV.
 Reset method: When the main control board can receive the feedback signal of EXV, F6 flashes, a manual system

restart id required before the system can resume operation.

Possible causes 2.11.4

 Electronic expansion valve coil not connected properly or has malfunctioned.
 Damaged main PCB.

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F6

Electronic expansion valve coil

connection on main PCB is loose1

Yes

Ensure the sensor is connected properly

No

Electronic expansion valve coil has

malfunctioned2

Yes

Replace the sensor

No

Replace outdoor main PCB

Figure 6-2.3: EXV coil wiring terminals

Procedure 2.11.5

Notes:

1. Electronic expansion valve coil connections are port CN70, CN71 and CN72 on the main PCB (labeled 18, 19 and 20, respectively, in Figure 5-2.1 in Part 5,

2.1 “Ports”).

2. The normal resistances between EXV coil wiring terminals RED and white / yellow / orange / blue are 40-50Ω. If any of the resistances differ from the value,

the EXV coil has malfunctioned.

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 Incorrect compressor inverter module address setting.
 Loosened communication wiring from the main PCB to

the inverter module.

 Bridge rectifier damaged.
 Main PCB damaged.
 Compressor inverter module damaged.

H0 error

Compressor inverter module address

setting is incorrect

Reset the compressor

inverter module address via

dial switch S7 on inverter

module

1

Communication wire from outdoor

main PCB CN26 to inverter module CN8/

CN9 is loosened

2

Reconnect the

communication wire

Both LED1 and LED2 on inverter module

are off when power on

3

No

No

Yes

Yes

Check the power supply

circuit

4

Yes

Replace the outdoor main PCB, is the

malfunction solved?

No

Normal

Yes

No

Replace the inverter module

2.12 xH0: Communication error

Digital display output 2.12.1

In the error code, 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1

representing compressor system A and 2 representing compressor system B.

Description 2.12.2

 1H0 indicates a communication error between the main control chip and the compressor A inverter driver chip.
 2H0 indicates a communication error between the main control chip and the compressor B inverter driver chip.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.12.3

 Trigger condition: Main control chip and inverter driver chip cannot communication for 2 minutes.
 Recover condition: Communication go back to normal.
 Reset method: Resume automatically.

Possible causes 2.12.4

Procedure 2.12.5

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6 - Diagnosis and Troubleshooting

S7 on inverter module

Inverter module address

0 for compressor inverter module A

1 for compressor inverter module B

Communication port CN26 on main PCB

Communication port CN8/CN9 on inverter module

CN41 Power for

Compressor inverter

CN61 High

pressure switch

connection port

Fuse 30A

CN30

Notes:

1. Compressor inverter module address is set through dial switch S7 on the inverter module. The compressor inverter module A/B location refers to the

wiring diagram.

2. Communication wire from outdoor main PCB CN26 to inverter module CN8/CN9.

3. LED1/2 on inverter module

4. Check the power supply for the compressor inverter module, port CN41 on filter board, the normal voltage should be DC310V; check the high pressure

switch connection port CN61 on filter board, the normal resistance should be zero; Check the single phase bridge and fuse on filter board; check the
connection cable from ODU main PCB port CN82 to filter board port CN30 which is DC310V power control port.

SMPS of

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Table 6-2.1: Specific error codes for error xH4

Specific error code1

Content

xL0

Inverter module protection

xL1

DC bus low voltage protection

xL2

DC bus high voltage protection

xL4

MCE error

xL5

Zero speed protection

xL7

Phase sequence error

xL8

Compressor frequency variation greater than 15Hz within one second protection

xL9

Actual compressor frequency differs from target frequency by more than 15Hz protection

Notes:

1. 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1 representing compressor system A and

2 representing compressor system B.

2.13 xH4: Inverter module protection

Digital display output 2.13.1

In the error code, 'x' is a placeholder for the compressor system (compressor and related electrical components), with 1

representing compressor system A and 2 representing compressor system B.

Description 2.13.2

 1H4 indicates compressor A inverter module protection.
 2H4 indicates compressor B inverter module protection.
 All units stop running.
 Error code is only displayed on the unit with the error.

Trigger / recover condition 2.13.3

 Trigger condition: Compressor appears three inverter module protections.
 Recover condition: Inverter module goes back to normal.
 Reset method: Manually restart.

Possible causes 2.13.4

 Inverter module protection.
 DC bus low or high voltage protection.
 MCE error.
 Zero speed protection.
 Phase sequence error.
 Excessive compressor frequency variation.
 Actual compressor frequency differs from target frequency.

Specific error codes for xH4 inverter module protection 2.13.5

If an xH4 error code is displayed, enter menu mode “n31” (refer to Part 5, 2.2.3 “menu mode”) to check the history error

code to check the following specific error code: xL0, xL1, xL2, xL4, xL5, xL7, xL8, xL9.

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Figure 6-2.4: LED indicators LED1 and LED2 on inverter module

Table 5-3.2: Errors indicated on LED1

LED1 flashing pattern

Corresponding error

Flashes 8 times and stops for 1 second, then repeats

xL0 - Inverter module protection

Flashes 9 times and stops for 1 second, then repeats

xL1 - DC bus low voltage protection

Flashes 10 times and stops for 1 second, then repeats

xL2 - DC bus high voltage protection

Flashes 12 times and stops for 1 second, then repeats

xL4 - MCE error

The specific error codes xL0, xL1, xL2 and xL4 can also be obtained from the inverter module LED indicators. If an inverter

module error has occurred, LED2 is continuously on and LED1 flashes.

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Figure 6-2.5: DC detection wire connection method

L0 protection

The DC bus wire connected incorrectly

1

Ensure the wire is

connected properly

The compressor wiring is connected

incorrectly

Reconnect the cables

based on wiring diagram

Replace the compressor

The inverter module is not well heat

dissipation

The IPM screws is loosen

Fasten IPM

screws again

The silica gel is coated not

well for heat radiation

Coat with silica

gel

The compressor has less than 12 hours

preheating before initial operating

Switch on power again to detect

whether the compressor can start

Refer to “P3 over current protection”

Replace the inverter

module

Ensure enough

preheating time

No

No

No

No

No

No

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

Yes

Yes

No

No

Disconnect
the power
supply

The resistance between 3 phases of

compressor is over 5Ω

The insulation resistance of

compressor is less than 100kΩ

L0: Inverter module protection 2.13.6

Note:

2. The DC bus wire should run from the N_in terminal on the inverter module, through the current sensor (in the direction indicated by the

arrow on the current sensor), and end at the N_out terminal on the inverter module.

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Figure 6-2.6: Inverter module terminals

L1 protection

The power supply is abnormal

Check the power supply

equipment

No output from bridge rectifier

Replace the inverter module

No

No

No

Yes

Yes

Yes

Yes

The DC bus voltage (P, N) is abnormal

1

The reactor performs well

Replace the

reactor

No

L1: DC bus low voltage protection 2.13.7

Note:

1. The normal DC voltage between terminals P and N on inverter module should be 450-650V. When the voltage is lower than 350V, L1

protection will be appeared.

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Figure 6-2.7: Inverter module terminals

L2 protection

The power supply is abnormal

Check the power supply

equipment

The DC bus voltage (P, N) is abnormal

1

Replace the 3-phase bridge

rectifier

Replace the inverter module

No

No

Yes

Yes

L2: DC bus high voltage protection 2.13.8

Note:

1. The normal DC voltage between terminals P and N on inverter module should be 450-650V. When the voltage is higher than 700V, L2

protection will be appeared.

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Part

6 - Diagnosis and Troubleshooting

S7 on inverter module

Inverter module address

0 for compressor inverter module A

1 for compressor inverter module B

L4 protection

ODU ventilation is not good

Remove barriers from heat

exchanger and air outlet of ODU

ODU stop valves are closed Open the ODU stop valves

Reconnect the cables based on

wiring diagram

The resistance between 3 phases of

compressor is over 5Ω

Replace the compressor

The insulation resistance of

compressor is less than 100Ω

Replace the compressor inverter

board, restart the unit and the error is

solved

Refer to P1 or P3 troubleshooting

No

No

Yes

Yes

Disconnect
the power
supply

Compressor wiring is not properly

Inverter module address setting1 and

discharge temperature sensor wiring is

not properly

Reset the inverter module address

and reconnect the discharge

temperature sensor cables

Yes

Normal

Yes

Yes

Yes

Yes

No

No

No

No

No

L4: MCE error 2.13.9

Notes:

1. Compressor inverter module address is set through dial switch S7 on the inverter module. The compressor inverter module A/B location refers to the

wiring diagram.

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