MDV MDV-V200W/DRN1 Installation guide

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

Part 4 Troubleshooting

1. Main PCB ports instructions ................................................................ 79

2. Main PCB parts instructions ................................ ................................ 82

3. Error code table ..................................................................................... 87

4. Troubleshooting .................................................................................... 89

78 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

No.

Content

Port voltage

1

Power input port of the main PCB

220V

2

Load output port (crankcase heater HAET 1&HEAT 2)

220V

3

Load output port

220V

4

Load output port

220V

5

Load output port

220V

6

Load output port (solenoid valve SV6 control)

220V

7

Load output port (contactor control POWER-C port)

220V

8

Load output port (solenoid valve SV2 control)

220V

9

Load output port (solenoid valve SV7 control)

220V

10

Load output port (solenoid valve SV4 control)

220V

11

Load output port (solenoid valve ST1 control)

220V

12

Inverter module drive port

The third pin on the left: DC3.3V Other pins: in dynamic change

13

Mutual inductor for DC main lead current inspection

In dynamic change

14

Voltage detection port of inverter module

DC540V, +15V, N

15

Power input port of the main PCB

220V

16

Discharge temperature detection port of inverter compressor

DC0~5V (in dynamic change)

17

Communication port

DC2.5~5V

18

Signal input port for high pressure and low pressure detection switch

DC0~5V (in dynamic change)

19

Outdoor ambient temperature detection port

DC0~5V (in dynamic change)

20

Current detection port

DC0~5V (in dynamic change)

21

Control port of DC fan 1

The right pin: +5V

22

Control port of DC fan 2

The right pin: +5V

23

Power output port of the main PCB

The first pin on the left: +12V

24

EXV drive port

The first pin on the left: DC12V The other four pins: in dynamic change

1. Main PCB ports instructions

1.1 20/22.4/26kW models

Ports instructions:

Troubleshooting 79

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

1

15

12

10

7

14

13

2

3 4

5

6

88

99

11

1616

17

1819

20

21

2222

2323

2424

2525

3030

31

28

29

3030

27

26

Setting switch of

outdoor unit address

Setting switch of

outdoor unit ability

setting switch of

indoor unit quantity

Force cooling keys

Point checking keys

1.2 40/45kW models

80 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

No.

Content

Port voltage

1

Discharge temp detection port of inverter compressor A

DC 0~5V (in dynamic change)

2

Discharge temp detection port of inverter compressor B

DC 0~5V (in dynamic change)

3

Temp detection port of inverter module radiator

DC 0~5V (in dynamic change)

4

Reserved

/

5

Reserved

/

6

Wiring port for communication between indoor and outdoor units, indoor unit network and network accounting

DC 2.5~2.7V 7

Phase-sequence detection port

380V

8

Power supply port of No. 1 transformer

220V

9

Power supply port of No. 2 transformer

220V

10

Load output port

220V

11

Drive port of EXVA

The first pin on left: DC 12V The other four pins: in dynamic change

12

Drive port of EXVB

13

Load output port

220V

14

Load output port

220V

15

Load output port

220V

16

Power output port of No.1 transformer

AC 13.5V (between upper two pins) AC 9V (between under two pins)

17

Power output port of No.2 transformer

AC 14.5V (between upper two pins) AC 14.5V (between under two pins)

18

Drive port of inverter module B

The third pin on left: DC 3.3V

19

Voltage detection port of inverter module B

DC 540V (between P and N), +DC 15V (between +15V and N)

20

Voltage detection port of inverter module A

DC 540V (between P and N), +DC 15V (between +15V and N)

21

Drive port of inverter module A

The third pin on left: DC 3.3V

22

Signal input port for system low pressure detection switch

DC 0~5V (in dynamic change)

23

Signal input port for system high pressure detection switch

DC 0~5V (in dynamic change)

24

Reserved

/

25

Reserved

/

26

Temperature detection port of ambient temp and condenser temp

DC 0~5V (in dynamic change)

27

Reserved

/

28

Control port of DC fan 1

The right pin: +5V

29

Control port of DC fan 2

The right pin: +5V

30

Current detection port of inverter compressor A and B

AC 0~7.8V (in dynamic change)

31

PCB power supply port

+5V(between GND and 5V pins) +12V(between GND and 12V pins)

Ports instructions:

Troubleshooting 81

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

No.

Display content

Note

Normal display*1

/ 1 0--

Capacity of this outdoor unit

7HP, 8HP, 10HP

2

1--

Total capacity requirements of indoor units

Actual value

3

2--

Revised total capacity requirements of outdoor unit

Actual value

4

3--

Operating mode*2

0, 2, 3, 4

5

4--

Fan speed*3

0, 1, 2, 3, 4, 5, 6, 7, 8, 9

6

5--

Average temperature of T2B/T2

Actual value

7

6--

T3 pipe temperature

Actual value

8

7--

T4 ambient temperature

Actual value

9

8--

Discharge temperature of inverter compressor

Actual value

10

9--

Discharge temperature of fixed compressor (reserved)

0

11

0--

Surface temperature of radiator (reserved)

0

12

1--

Open degree of EXV

Actual value=display×8

13

2--

Current of inverter compressor

Actual value

14

3--

Current of fixed compressor (reserved)

0

15

4--

Discharge pressure (reserved)

0

16

5--

Priority mode*4

0, 1, 2, 3, 4

17

6--

Total quantity of indoor units

Actual value

18

7--

Quantity of running units

Actual value

19

8--

The last error or protection code

Display 00 if it has no error or protection code

20

9--

--

Check over

Inverter compressor drive chip

Main control chip

Communication chip

LED digital tube display

Function setting dial switch

SW1: forced cooling button

SW2: check button

2. Main PCB parts instructions

2.1 20/22.4/26kW models

2.1.1 Check content instructions (SW2)

Note: 82 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

ENC2: Outdoor unit capacity setting

Outdoor unit capacity setting: 0-2 are available (capacity code0—20kW; capacity code 1—22.4kW) ; capacity code 2—26kW)

ENC3: Quantity of indoor units setting

The quantity of indoor unit is 0-15 0~9 on ENC3 refer to 0~9 indoor units; A~F on ENC3 refer to 10~15 indoor units.

S5: Locking modes selection

Heating priority mode (factory default)

Cooling priority mode

No.63 indoor unit running mode priority when there has No.63 indoor unit or larger capacity requirement priority when there has on No.63 indoor unit

Only response to heating mode

Only response to cooling mode

S6: Addressing mode selection

Auto addressing mode

Manual addressing mode (factory default)

Clean the indoor unit address (only available for auto searching new indoor unit)

ENC2

ENC3

1 2 3

S5

ON

1 2 3

S5

ON

1 2 3

S5

ON

1 2 3

S5

ON

1 2 3

S5

ON

1 2 3

S6

ON

1 2 3

S6

ON

1 2 3

S6

ON

*1: Display compressor frequency when system is running and display the quantity of indoor unit which communicate with outdoor unit when system is standby. *2: Operating mode: 0 – standby mode; 2 – cooling mode; 3 – heating mode; 4 – forced cooling. *3: Fan speed: 0 – fan stop; 1~9 – speed increase sequentially; 9 – the maximum fan speed. *4: Priority mode: 0 – heating priority; 1 – cooling priority; 2 – first running mode priority; 3 – only respond heating mode; 4 – only respond cooling mode.

2.1.2 System setting dial switches instructions

Troubleshooting 83

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

No.

Normal display

Content (present frequency)

Note

1

0.- -

Outdoor unit address

0 (individual type)

2

1.- -

Outdoor unit capacity setting

Refer to note 1

3

2.- -

Outdoor unit quantity

Reserved

4

3.- -

Setting quantity of indoor units

Actual value=display value

5

4.- -

Total capacity of outdoor units

Capacity requirement

6

5.- -

Total capacity requirement of indoor units

Actual value=display value

7

6.- -

Revised total capacity requirements of outdoor unit

Actual value=display value

8

7.- -

Running mode

Refer to note 2

9

8.- -

Actual running capacity of this outdoor unit

Capacity requirement

10

9.- -

No.1 fan speed3

Refer to note 3

11

10.- -

No.2 fan speed3

Refer to note 3

12

11.- -

T2B/T2 average temperature

Actual value=display value

13

12.- -

T3 pipe temperature

Actual value=display value

14

13.- -

T4 ambient temperature

Actual value=display value

15

14.- -

Discharge temperature of No. 1 inverter compressor

Actual value=display value

16

15.- -

Discharge temperature of No. 2 inverter compressor

Actual value=display value

17

16.- -

Reserved

/

18

17.- -

Current of No. 1 inverter compressor

Actual value=display value

19

18.- -

Current of No. 2 inverter compressor

Actual value=display value

20

19.- -

EXVA opening degree

Pulsed value=display value×8

21

20.- -

EXVB opening degree

Pulsed value=display value×8

22

21.- -

High pressure

Reserved

SW2: check button

SW1: forced cooling button

Dial switch

Inverter compressor drive chip

Main control chip

LED digital tube display

Communication chip

2.2 40/45kW models

2.2.1 Query content instructions

84 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

23

22.- -

T3B / 24

23.- -

Indoor units quantity

Actual value=display value

25

24.- -

Running indoor units quantity

Actual value=display value

26

25.- -

Mode priority4

Refer to note 4

27

26.- -

Silent mode5

Refer to note 5

28

27.- -

Static pressure mode6

Refer to note 6

29

28.- -

DC voltage A

Actual value=display value×10

30

29.- -

DC voltage B

Actual value=display value×10

31

30.- -

Reserved

/

32

- -

Reserved

/

33

- -

Over

ENC2: Outdoor unit capacity setting

Outdoor unit capacity setting: 4-5 are available (capacity code4—40kW; capacity code 5—45kW)

ENC3+S12: Quantity of indoor units setting

The quantity of indoor unit is 0-15 0~9 on ENC3 refer to 0~9 indoor units; A~F on ENC3 refer to 10~15 indoor units.

The quantity of indoor unit is 16-31 0~9 on ENC3 refer to 16~25 indoor units; A~F on ENC3 refer to 26~31 indoor units.

The quantity of indoor unit is 32-47 0~9 on ENC3 refer to 32~41 indoor units; A~F on ENC3 refer to 42~47 indoor units.

The quantity of indoor unit is 48-63 0~9 on ENC3 refer to 48~57 indoor units; A~F on ENC3 refer to 58~63 indoor units.

S3: Silent mode selection

Nighttime silent mode (factory default)

Silent mode

ENC2

ENC3

S12

ON

ENC3

S12

ON

ENC3

S12

ON

ENC3

S12

ON

1 2

S3

ON

1 2

S3

ON

S3

S4

S5

S6

ENC4

ENC1

ENC3

S12

S3

S7

S8

ENC1

S1

Note: When the outdoor unit is in standby, the LED digital tube will display the indoor unit’s quantity which can communicate with outdoor unit, and it will display inverter compressor running frequency when there has capacity requirement.

1. Outdoor unit capacity setting: capacity code4—40kW; capacity code 5—45kW;

2. Running mode: 0—closed; 2—cooling mode; 3—heating mode; 4—forced cooling mode.

3. Fan speed: 0—closed; 1~10—fan speed increase in sequence.

4. Mode priority: 0—heating priority; 1—cooling priority; 2—No.63 indoor unit running mode priority when there has No.63 indoor unit or larger capacity requirement priority when there has on No.63 indoor unit; 3—only response to heating; 4—only response to cooling.

5. Silent mode: 0—nighttime silent mode; 1—silent mode; 2—reserved; 3—no silent mode.

6. Static pressure mode: 0—no static pressure; 1—low static pressure; 2—medium static pressure; 3—high static pressure.

2.2.2 System setting dial switches instructions

Troubleshooting 85

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

Super silent mode

No silent mode

S1: Starting time setting

Starting time is 5 minutes

Starting time is 12 minutes (factor default) S2: Night silent time selection

Nighttime silent time 6h/10h (factory default)

Nighttime silent time 6h/12h

Nighttime silent time 8h/10h

Nighttime silent time 8h/12h S4: Static pressure mode selection

No static pressure mode (factory default)

Low static pressure mode (should be customized)

Medium static pressure mode (should be customized)

High static pressure mode (should be customized)

S5: Locking modes selection

Heating priority mode (factory default)

Cooling priority mode

No.63 indoor unit running mode priority when there has No.63 indoor unit or larger capacity requirement priority when there has on No.63 indoor unit

Only response to heating mode

Only response to cooling mode S6: Addressing mode selection

Auto addressing mode

Manual addressing mode (factory default)

Clean the indoor unit address (only available for auto searching new indoor unit)

1 2

S3

ON

1 2

S3

ON

1 2

S1

ON

1 2

S1

ON

1 2 3

S2

ON

1 2 3

S2

ON

1 2 3

S2

ON

1 2 3

S2

ON

1 2 3

S4

ON

1 2 3

S4

ON

1 2 3

S4

ON

1 2 3

S4

ON

1 2 3

S5

ON

1 2 3

S5

ON

1 2 3

S5

ON

1 2 3

S5

ON

1 2 3

S5

ON

1 2 3

S6

ON

1 2 3

S6

ON

1 2 3

S6

ON

86 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

S7: ON/OFF for indoor unit quantity setting function

Indoor unit quantity setting function is open (factory default)

Indoor unit quantity setting function is closed

ENC4: Outdoor unit network address setting

Outdoor unit network address setting (0-7 is effective)

Error code

Content

Note

E1

Reserved

E2

communication fault between the outdoor and indoor units

E4

T3 & T4 temperature sensor fault

E5

Voltage protection fault or a lack of Phase B、Phase N

E6

DC fan motor error

E7

Discharge temp sensor error

EA

A fan in the A region run for more than 5 minutes in Heat mode

EB

2 times of E6 protection in 10 minutes

H0

Communication error between main control chip and module chip

H1

Communication error between main control chip and communication chip

H4

3 times of P6 protection in 30 minutes

H5

3 times of P2 protection in 30 minutes

H7

The number of indoor units decreases

H8

Reserved

P0

Top temperature protection of inverter compressor

P1

High pressure protection

P2

Low pressure protection

P3

Current protection of inverter compressor

P4

Compressor discharge temperature protection

P5

Outdoor condenser high temperature protection

P6

Module protection (don’t display)

P8

Typhoon protection

P9

Module protection of DC fan

PE

Evaporator high temperature protection

L0

Inverter module error

L1

Low voltage protection of DC generatrix

L2

High voltage protection of DC generatrix

L3

Reserved

L4

MCE error/ synchronization/ closed loop

L5

Zero speed protection

L6

Reserved

L7

Phase sequence error

ENC4

3. Error code table

3.1 20/22.4/26kW models

Troubleshooting 87

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

L8

Frequency difference in one second more than 15Hz protection

L9

Frequency difference between the real and the setting frequency more than 15Hz protection

Error code

Content

Note

E1

Phase protection

E2

Indoor units and master unit communication error

E4

Pipe temp T3/ambient temp T4 sensor error

E5

Voltage error

E6

DC fan motor error

E7

Discharge temp sensor error

EA

T3 pipe temperature protection in heating mode

EB

E6 protection appears twice in 10 minutes

H0

Communication error between main control chip and module chip

H1

Communication error between main control chip and communication chip

H4

P6 protection appears three times in 60 minutes

H5

P2 protection appears three times in 60 minutes

H6

P4 protection appears three times in 100 minutes

H7

Quantity of indoor units decrease

H8

High pressure sensor error

H9

P9 protection appears three times in 60 minutes

P0

Top temperature protection of inverter compressor

P1

High pressure protection

P2

Low pressure protection

P3

Current protection of inverter compressor

P4

Discharge temperature protection

P5

Pipe temperature protection

P6

Module protection (don’t display)

P8

Typhoon protection

P9

Module protection of DC fan

PL

Temperature protection of inverter module

C7

PL protection appears three times in 60 minutes

L0

Inverter module error

L1

Low voltage protection of DC generatrix

L2

High voltage protection of DC generatrix

L3

Reserved

L4

MCE error/ synchronization/ closed loop

L5

Zero speed protection

L6

Reserved

L7

Phase sequence error

L8

Frequency difference in one second more than 15Hz protection

L9

Frequency difference between the real and the setting frequency more than 15Hz protection

3.2 40/45kW models

88 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

Error code

Content

r1

Lack of refrigerant

r2

Obvious lack of refrigerant

r3

Serious lack of refrigerant

R1

Too much refrigerant

R2

Serious too much refrigerant

E1: Phase sequence error

The 3-phase sequence of power supply is wrong. (The A, B, C terminal of three-phase power supply should meet compressor phase sequence requirement. If the phase sequence is adverse, the compressor will operate inversely.

Exchange any two of the 3-sequence

Some power supply terminals are loose, if there has phase loose, the

compressor will operate abnormally,

and the current is very large

Fasten each phase joint of

power supply.

Outdoor main control board is damaged

Replace the outdoor main control board

No

Yes

Note: P6, L0~L9 error codes can’t display on digital tube automatically, these error codes will display on digital tube only through SW3 button (press SW3 ten times, every one second for a time)

The large capacity V4+ individual system (56-90kW) have the function of refrigerant volume automatic judgment. When all the indoor units are in cooling or heating mode, the system will be in refrigerant volume judgment mode automatically. If the system judges that the refrigerant volume is normal, the system will operate normally, no error code will display. If the system judges that the refrigerant volume is abnormal, corresponding error code will display on digital tube. When only partial indoor units are in cooling or heating mode, the system will not judge the refrigerant volume and the digital tube will reserve the last judging result.

4. Troubleshooting

4.1 E1: Phase sequence error

Note: If the wiring connection of each outdoor unit is according to A, B, C phase sequence, when the quantity of outdoor units is large, the current difference between C phase and A, B phase will be very large for the power supply load of each outdoor unit is on C phase, it is very easy to lead to air switch break and wiring terminal burnout. So when the quantity of outdoor units is large, the phase sequence should be staggered, then the current can be distributed to the three phases equally.

Troubleshooting 89

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

E2: Indoor units and outdoor unit communication error

Communication wires P, Q, E are short circuit or disconnected (Measure the resistance among P Q and E, the normal resistance is 120Ω)

Reconnect the communication wires

Communication wires are not

connected in line shape

The communication wires are interfered by high voltage power (voltage over 220V is high voltage power)

Communication wires are close to electromagnetic interference source. Such as transfer, strong fluorescent

lamp, etc.

Remove the interference source, or use device to filter out the interference

The length of communication wire is over 1200m

Adjust the wire length to less than 1200m or strengthen the signal

Yes

Connect the communication wires

in line shape

No

Yes

Ensure the communication wires and high voltage wires do not twining

Yes

Outdoor main control board is damaged

Replace the outdoor main control board

4.2 E2: Indoor units and outdoor unit communication error

90 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

E4: T3/T4/T7 sensor error

T3/T4/T7 port on main control board is loose

Fasten the T3/T4 port

T3/T4/T7 sensor is short circuit or disabled (Using a multimeter to measure resistance, if the resistance is

too small, the sensor is short circuit, if

the resistance in certain temperature is not consistent with attached table 1(2), the sensor is disabled)

Replace the sensor

No

Yes

connected with sheet metal

After being reconnected, the

Outdoor main control board is damaged

Replace the outdoor main control board

4.3 E4: Pipe temp T3/ambient temp T4 sensor error; E7: Discharge temp sensor T7 error

Case: There is no display on main control board, and the problem still exists after replacing main control board. Voltage values on measuring plate (such as 220V, 5V, 12V, etc.) are normal; after measuring resistance value of sensor, find that T4 thermo-bulb is earth-continuity, and further discover that the thermal cable of T4 sensor is punched by bolt, as follows:

T4 sensor is worn out and

Troubleshooting 91

system becomes normal

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

E5: Voltage error

Voltage of power supply is too high or too low (the normal voltage between A and N (B and N, C and N) should be 163V~268V)

Provide normal power supply

Check the high voltage circuit. Whether

, fan

, inverter module

is output error③, etc.

Replace the inverter module

or repair related parts

No

Yes

Outdoor main control board is damaged

Replace the outdoor main control board

4.4 E5: Voltage error

the compressor is short circuit①

motor is short circuit②

Note:

1. How to check whether the compressor is short circuit①:

The normal resistance value of inverter compressor among U V W is 0.7~1.5Ω, and infinity to earth. If the resistance value is out of the range, the compressor is abnormal.

2. How to check whether the fan motor is short circuit②:

The normal value of DC fan motor coil among U V W is less than 10Ω, and the value of AC fan motor coil is from a few ohm to hundreds of ohm for different fan motor model. If the measured value is 0Ω, the fan motor is short circuit.

3. How to check whether the inverter module is output error③:

Dial the multimeter to diode file, black pen on P and red pen respectively on U,V,W, if the multimeter displays 0.4~0.7 V, it is normal; Red pen on N, black pen respectively on U,V,W, if the multimeter displays 0.4~0.7 V, it is normal. Satisfying the above two conditions at the same time indicates that the inverter module has no problem.

92 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

E6: DC fan motor error

There has strong airflow against fan wheel when the fan is running

It belongs to normal protection

DC fan wiring connection is not consistent with wiring nameplate

Wiring connection consists with wiring nameplate

The voltage between PN of the fan transfer board is not for 255V to 367V

The fuse on the filter is disconnected or damaged

Reconnect the fuse or replace the fuse

Insure the power supply is 380-415V, 3N, 50Hz

Outdoor main control board is damaged

Replace the outdoor main control board

Fan motor is damaged

Replace the fan motor

No

Yes

4.5 E6: DC fan motor error; EB: E6 protection appears twice in 10 minutes

Troubleshooting 93

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

EA: T3 pipe temperature protection in heating mode

The outdoor ambient temperature is higher than the unit operating limitation in heating mode

It belongs to normal protection

System is lack of refrigerant①. (Refrigerant recharging is not according

refrigerant leakage)

Add refrigerant or check up the leakage of the system

Outdoor heat-exchanger is blocked

Remove the obstacle

T3 temperature sensor is damaged

Replace the temperature sensor

Outdoor main control board is damaged

Replace the outdoor main control board

Yes

No

4.6 EA: T3 pipe temperature protection in heating mode

When T3 pipe temperature exceeds 27oC lasting for five minutes in heating mode, the unit will display EA error.

to the requirement, or there has

1. The phenomenon of lack of refrigerant②:

Top temperature and discharge temperature of all compressors are higher than normal value, discharge pressure and suction pressure are both lower than normal value, current is lower than normal value, suction pipe may be frosting. All the phenomenon will disappear after recharging refrigerant.

94 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

H0/H1

Power supply for main PCB, transformer 1 and transformer 2 terminals are abnormal①

The transformer on main control board is disabled②

Remove the interference

There has electromagnetic interference nearby the unit. Such as High-frequency transmitter or other high strength radiation device

Replace the transformer

Provide normal power supply

Outdoor main control board is damaged

Replace the outdoor main control board

No

Yes

4.7 H0: Communication error between main control chip and module chip; H1: Communication error between main control chip and communication chip

Note:

1. How to check whether power supply of main PCB, transformer 1 and transformer 1 terminals are abnormal①

The voltage of power supply for transformer 1 and transformer 1 terminals are both 220V, the voltage between ―GND‖ and ―+5V‖ terminals of Power supply for main PCB ports is 5V, and between ―GND‖ and ―+12V‖ terminals of Power supply for main PCB ports is 12V.

2. How to check whether the transformer on main control board is disabled②

The voltage of power supply for transformer 1 and transformer 2 terminals are both 220V, the voltage of transformer 1 output terminals is AC9V (between left two pins) and AC13.5V (between rights two pins); the voltage of transformer 2 output terminal is AC14.5V (between left two pins) and AC 14.5V (between rights two pins). If the voltage is out of the range, the transformer is disabled.

Troubleshooting 95

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

H7: Quantity of indoor units decrease error

Communication terminals P Q E are loose

Fasten the communication terminals

Yes

Transformer of IDU is disabled①

Replace the transformer

IDU are not unified power supply*

Insure all the IDU be unified power supply

485 communication IC is disabled②

IDU PCB is disabled

Replace the IDU PCB

No

Yes

Some IDU are assigned the

same address

Some IDU are power off

Set the IDU addresses differently

Power on all IDU

No

Yes

P Q E terminals

4.8 H7: Quantity of indoor units decrease error

H7 error will display when the quantity of indoor units decrease above 3 minutes.

Note:

1. How to check whether the transformer of IDU is disabled①

The voltage input for IDU transformer is 220V, the voltage output of is AC9V (yellow-yellow) and AC13.5V (brown-brown)

2. How to check whether the 485 communication IC is disabled②

The normal voltage between ―P‖ and ―GND‖ is DC2.5~2.7V, between ―Q‖ and ―GND‖ is DC2.5~2.7V. If the voltage is out of the normal range, the 485 communication IC is disabled.

*Indoor units should be unified power supply, which can prevent compressor from liquid hammer caused by dropped indoor units with EXV unclosed.

96 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

High pressure sensor is

short circuit or disabled①

Replace the sensor

System is lack of refrigerant②.

leakage)

Add refrigerant or check up the leakage of the system

The low pressure side is blocked③

closed strop valve, dirty filter, etc.

Make sure all valves are open, clean

the system should be clean

Yes

The heat exchange of evaporator

of the air outlet, etc.

Check the system and fixed up the error

No

H8: High pressure sensor error

High pressure sensor connection port on main control board is loose

Fasten the connection port

Yes

Outdoor main control board is damaged

Replace the outdoor main control board

4.9 H8: High pressure sensor error

When the discharge pressure is lower than 0.3MPa, the system will display H8 error, the ODU in standby. When the discharge pressure is back to normal, H8 disappears and normal operation resumes.

(Refrigerant recharging is not according to the requirement, or there has refrigerant

for squashed pipe, closed EXV,

the filter, if the filter is blocked by ice,

is not good. It may be caused by dirty heat changer, abnormal IDU fan running, some barrier in front

Note:

1. How to check whether the high pressure sensor is short circuit or disabled①

Measure the resistance among the three terminals of the pressure sensor, if the resistance value is megohm or infinite, the pressure sensor is disabled, otherwise, it may be normal.

2. The phenomenon of lack of refrigerant②:

Top temperature and discharge temperature of all compressors are higher than normal value, discharge pressure and suction pressure are both lower than normal value, current is lower than normal value, suction pipe may be frosting. All the phenomenon will disappear after recharging refrigerant.

3. The phenomenon of the low pressure side is blocked③:

The discharge temperature is higher than normal value*, low pressure is lower than normal value*, current is lower than normal value* and suction pipe may be frosting. *The normal system running parameters please refer to attached table 3.

Troubleshooting 97

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

P1: High pressure protection

The heat exchange of condenser dirty heat changer, abnormal ODU each other, etc.

Check the system and fixed up the error

The high pressure side of the system is valve or closed stop valve

Make sure all valves are open, the obstacle

Refrigerant is excess②

Discharge part of the refrigerant. Add some oil if it leaks during the discharge

System contains air or nitrogen③

Discharge the entire refrigerant. Then Add oil to the system if it leaks.

Yes

No

Yes

Outdoor main control board is damaged

Replace the outdoor main control board

4.10 P1: High pressure protection

When the pressure is over 4.4MPa, the system will display P1 protection, the ODU in standby. When the pressure is lower than 3.2MPa, P1 disappears and normal operation resumes.

is not good. It may be caused by fan running, ODU are too near to

blocked① for squashed pipe, blocked

check the system, and remove

vacuum the system and refill the refrigerant.

Note:

1. The phenomenon of The high pressure side of the system is blocked①:

The high pressure is higher than normal value, the low pressure is lower than normal value, and the discharge temperature is higher than normal value.

2. The phenomenon of the refrigerant is excess②:

The high pressure is higher than normal value, the low pressure is higher than normal value, and the discharge temperature is lower than normal value.

3. The phenomenon of the system contains air or nitrogen③:

The high pressure is higher than normal value, current is larger than normal value, discharge temperature is higher than normal value, compressor makes noise, pressure meter do not display steady. *The normal system running parameters please refer to attached table 3. *If the system install three-phase protector, and the three-phase protector connect with high pressure switch in series connection, the system will display P1 protection when fist power on, and P1 protection will disappear after system is steady. *If the system install three-phase protector, and the three-phase protector connect with low pressure switch in series connection, the system will display P2 protection when fist power on, and P2 protection will disappear after system is steady.

4.11 P2/H5: Low pressure protection

When the pressure is lower than 0.05MPa, the system will display P2 protection, the ODU in standby. When the pressure is higher than 0.15MPa, P2 disappears and resumes normal operation. H5 error will display when system appear 3 times P2 protection in 60 minutes, it cannot resume automatically, and it can resume only by restarting the machine.

98 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

P2/H5: Low pressure protection

System is lack of refrigerant①.

leakage)

Add refrigerant or check up the leakage of the system

The low pressure side is blocked②

closed strop valve, dirty filter, etc.

Make sure all valves are open, clean

the system should be clean

Yes

The heat exchange of evaporator

of the air outlet, etc.

Check the system and fixed up the error

Yes

No

Outdoor main control board is damaged

Replace the outdoor main control board

(Refrigerant recharging is not according to the requirement, or there has refrigerant

for squashed pipe, closed EXV,

the filter, if the filter is blocked by ice,

is not good. It may be caused by dirty heat changer, abnormal IDU fan running, some barrier in front

Note:

1. The phenomenon of lack of refrigerant①:

Top temperature and discharge temperature of all compressors are higher than normal value, discharge pressure and suction pressure are both lower than normal value, current is lower than normal value, suction pipe may be frosting. All the phenomenon will disappear after recharging refrigerant.

2. The phenomenon of the low pressure side is blocked②:

The discharge temperature is higher than normal value*, low pressure is lower than normal value*, current is lower than normal value* and suction pipe may be frosting. *The normal system running parameters please refer to attached table 3. *If the system install three-phase protector, and the three-phase protector connect with high pressure switch in series connection, the system will display P1 protection when fist power on, and P1 protection will disappear after system is steady. *If the system install three-phase protector, and the three-phase protector connect with low pressure switch in series connection, the system will display P2 protection when fist power on, and P2 protection will disappear after system is steady.

Troubleshooting 99

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

P3: Compressor current protection

The indoor load is too large①

Make sure the ratio of connectable IDU is less than 130% or add ODU

No

Yes

The heat exchange of condenser dirty heat changer, abnormal ODU each other, etc.

Check the system and

fixed up the error

No

Yes

The high pressure side of the system is valve or closed stop valve

Make sure all valves are open, the obstacle

Refrigerant is excess③

Discharge part of the refrigerant. Add some oil if it leaks during the discharge

System contains air or nitrogen④

Discharge the entire refrigerant. Then

Add oil to the system if it leaks.

Yes

No

Yes

High voltage short circuit or compressor error⑤

Make sure the high voltage circuit is normal, or replace the compressor

Yes

No

Outdoor main control board is damaged

Replace the outdoor main control board

4.12 P3: Current protection of inverter compressor P3: When the current of inverter compressor is over12A, the system will display P3 protection, the ODU in

standby. When the current goes back to normal range, P3 disappears and normal operation resumes.

is not good. It may be caused by

fan running, ODU are too near to

blocked② for squashed pipe, blocked

check the system, and remove

vacuum the system and refill the refrigerant.

Note:

1. The phenomenon of the indoor load is too large①:

The suction temperature and discharge temperature are both higher than normal value.

2. The phenomenon of The high pressure side of the system is blocked②:

The high pressure is higher than normal value, the low pressure is lower than normal value, and the discharge temperature is higher than normal value.

3. The phenomenon of the refrigerant is excess③:

The high pressure is higher than normal value, the low pressure is higher than normal value, and the discharge temperature is lower than normal value.

4. The phenomenon of the system contains air or nitrogen④:

The high pressure is higher than normal value, current is larger than normal value, discharge temperature is higher than normal value, compressor makes noise, pressure meter do not display steady.

5. How to check whether compressor is error⑤:

Measure the resistance between two terminals among the three terminals of compressor. The resistance between two terminals is 2-5Ω, the resistance between each terminal and ground is infinity, if the resistance is out of the normal range, the compressor

100 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

P4/H6

System is lack of refrigerant②.

leakage)

Add refrigerant or check up

the leakage of the system

The low pressure side is blocked③ closed strop valve, dirty filter, etc.

Make sure all valves are open, clean the system should be clean

The indoor load is too large④

Make sure the ratio of connectable IDU is less than 130% or add ODU

System contains air or nitrogen⑤

Discharge the entire refrigerant. Then vacuum the system if it leaks.

T7C2/T7C3/T7C4 sensor is short circuit or disabled①.

Replace the sensor

Yes

No

Yes

Outdoor main control board is damaged

Replace the outdoor main control board

is error. *The normal system running parameters please refer to attached table 3.

4.13 P4: Discharge temperature protection; H6: P4 protection appears three times in 100 minutes

(Refrigerant recharging is not according to the requirement, or there has refrigerant

for squashed pipe, closed EXV,

filter, if the filter is blocked by ice, the

the system and refill the refrigerant. Add oil to

Note:

H6 error cannot resume automatically, and it can resume only by restarting the machine.

1. How to check whether the T7C2/T7C3/T7C4 sensor is short circuit or disabled①:

Using a multimeter to measure resistance, if the resistance is too small, the sensor is short circuit, if the resistance in certain temperature is not consistent with attached table 2, the sensor is disabled

2. The phenomenon of lack of refrigerant②:

Top temperature and discharge temperature of all compressors are higher than normal value, discharge pressure and suction pressure are both lower than normal value, current is lower than normal value, suction pipe may be frosting. All the phenomenon will disappear after recharging refrigerant.

3. The phenomenon of the low pressure side is blocked③:

The discharge temperature is higher than normal value*, low pressure is lower than normal value*, current is lower than normal value* and suction pipe may be frosting.

4. The phenomenon of the indoor load is too large④:

The suction temperature and discharge temperature are both higher than normal value.

5. The phenomenon of the system contains air or nitrogen⑤:

The high pressure is higher than normal value, current is larger than normal value, discharge temperature is higher than normal value, compressor makes noise, pressure meter do not display steady. *The normal system running parameters please refer to attached table 3.

4.14 P5: Condenser temperature protection

When condenser temperature is over 65℃, the system will display P5 protection, the ODU in standby. When

Troubleshooting 101

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

P5: Condenser temperature protection

T3 port on main control board is loose

Fasten the T3 port

T3 sensor is short circuit or disabled①

Replace the sensor

Yes

The indoor load is too large②

Make sure the ratio of connectable IDU is less than 130% or add ODU

No

Yes

No

The heat exchange of condenser dirty heat changer, abnormal ODU each other, etc.

Check the system and fixed up the error

No

Yes

The high pressure side of the system is valve or closed stop valve

Make sure all valves are open, the obstacle

System contains air or nitrogen④

Discharge the entire refrigerant. Then Add oil to the system if it leaks.

Yes

No

Yes

No

Outdoor main control board is damaged

Replace the outdoor main control board

the temperature goes back to normal range, P5 disappear and normal operation resumes.

is not good. It may be caused by fan running, ODU are too near to

blocked③ for squashed pipe, blocked

check the system, and remove

vacuum the system and refill the refrigerant.

Note:

1. How to check whether the T3 sensor is circuit or disabled①:

Using a multimeter to measure resistance, if the resistance is too small, the sensor is short circuit, if the resistance in certain temperature is not consistent with attached table 1, the sensor is disabled

2. The phenomenon of the indoor load is too large②:

The suction temperature and discharge temperature are both higher than normal value.

3. The phenomenon of The high pressure side of the system is blocked③:

The high pressure is higher than normal value, the low pressure is lower than normal value, and the discharge temperature is higher than normal value.

4. The phenomenon of the system contains air or nitrogen④:

The high pressure is higher than normal value, current is larger than normal value, discharge temperature is higher than normal value, compressor makes noise, pressure meter do not display steady.

102 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

L1: low voltage protection

L4: MCE error

L2: high voltage protection

L8: frequency difference in one second more than 15Hz

L9: frequency difference between the real and the

than 15Hz

L0: module protection

L5: Zero speed protection

L7: Phase sequence error

P6, L0~L9 error codes can’t

a time)

Check module and compressor

Check power supply of module

Check module and electric circuit

Check electric circuit and compressor

Check module and wiring connection

Check compressor

H4 will display if P6 occur 3 times in 30 minutes

Check whether inverter

DC generatrix is connected connected inversely

4.15 P6/H4: Module protection

P6, L0~L9 error codes can’t display on digital tube automatically, these error codes will display on digital tube

only through SW3 button (pressure SW3 ten times, every one second for a time) If the system display three times P6 protection in 60 minutes, the system will stop and display H4 error code. When the system displays H4 error code, the system can resume only by restarting the machine. At this time, malfunction should be disposed promptly to avoid further damage.

module is broken, and eliminate the situation that

display on digital tube automatically, these error codes will display on digital tube only through SW3

button (pressure SW3 ten

times, every one second for

setting frequency more

Troubleshooting 103

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

N

3 2 4

5

1

P

1) L0 troubleshooting Step 1: Compressor check

Measure the resistance between each two of U, V, W terminals of the compressor, all the resistance should be the same and equal to 0.9~5 Ohms. (Fig. A and Fig. B) Measure the resistance between each of U, V, W terminals of the compressor to ground (Fig. C), all the resistance should trend to infinity (Fig. D), otherwise the compressor has been malfunction, needs to be replaced.

Fig. A Fig.B Fig.C Fig.D If the resistance value are normal, then go to step 2. Step 2: Module check

1) DC voltage between terminal P and terminal N should be 1.41 times of the local power supply voltage.

2) DC voltage between terminal 1 and 2 should be 510V～580V.

3) Disconnect the terminal 3, 4, and 5 from inverter compressor. Measure the risistance between any two terminals among terminal 1, 2, 3, 4, 5. All the values should be infinity. If any of the value approximates to 0, the inverter module is damaged and should be replaced.

After replaced the inverter module, if the system is still abnormal, then go to step 3. Step 3: DC generatrix check Direction of the current in DC supply wire which is running through the inductor should be the same as the direction of arrow marked on the inductor.

104 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

1

2

3-Phase bridge rectifier

Filter board

2) L1/L4 troubleshooting

Step 1: Check the DC voltage between 1 and 2 terminal, the normal value should be 510V~580V, if the voltage is lower than 510V, go to step 2.

Step 2: Check whether the wires of rectifier circuit are loose or not. If wires are loosen, fasten the wires. If wires are OK, replace the main PCB.

3) L2 troubleshooting

Step 1: Check the DC voltage between 1 and 2 terminal, the normal value should be 510V~580V, if the voltage

Troubleshooting 105

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

Turn the measure

electrolytic capacitors

1

2

is higher than 580V, go to step 2.

Step 2: Check the voltage between the two electrolytic capacitors, the normal value should be 510V~580V.

range of the meter to 1kV, measure the voltage between two

If the value is not in the range, that means the power supply for electrolytic capacitors has problem, you should check the power supply, whether the voltage is too high and whether the voltage is stable. If the voltage value is normal, then the main PCB has malfunction, it needs to be replaced.

4) L8/L9 troubleshooting

Step 1: Compressor check

Measure the resistance between each two of U, V, W terminals of the compressor, all the resistance should be the same and equal to 0.9~5 Ohms. (Fig. A and Fig. B) Measure the resistance between each of U, V, W terminals of the compressor to ground (Fig. C), all the resistance should trend to infinity (Fig. D), otherwise the compressor has been malfunction, needs to be replaced.

Fig. A Fig. B Fig. C Fig. D

If the resistance value are normal, then go to step 2. Step 2: Disconncet the power wiring from the compressor(named compressor A) of the faulted system(named system A). If there is a system running normally nearby(named system B): Extend the power line of the inverter compressor of system B, connect compressor A to the control box of system B, make sure that the U, V, W terminals are connected in right order, then start system B.

106 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

The oil is a little yellowing, but

quality is OK

The oil is black, it has been carbonized

If compressor A can start normally, that means compressor is OK, the control box of system A is malfunction, then raplace the main PCB of system A with correct wire connection. If compressor A can not start normally, that means compressor A is demaged, needs to be replaced.

If there is no normal system nearby:

Replace the main PCB of system A with correct connection, if compressor A can start normally, it means the main PCB which is replaced is damaged. If compressor A still can’t start normally, replace the compressor.

5) Guide for compressor replacement

Step 1: Take out the compressor from the faulty outdoor unit, pour out the oil from the compressor according to

the method illustrated. Normally the oil will outflow from the discharge pipe of the compressor.

Step 2: check the oil of the system Normally the oil is clear and transparent, if it is a little yellowing, it is also OK. However, if the oil is become black, feculent, or even there is impurity in the oil, that means the system has problems and the oil has gone bad, the oil need to be replaced.

it is clear and transparent, the

Troubleshooting 107

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

The oil is still transparent,

The oil is still transparent, but there is impunity in the oil, the

and gray

copper scrap

The compressor can’t be lubricated effectively.

The electric heat will rise and the temperature of the motor becomes increasingly high

The motor is burned and the compressor is damaged at last

The scroll plate, the crankshaft and the bearing of the compressor is worn

Abrasion leads to larger load, higher current

but there is impunity in the oil, the impunity may clog

impunity may clog the filter

The oil becomes cloudy

The oil contains a lot of

If the oil has gone bad:

108 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

The crankshaft is

The scroll plate of the

The crankshaft is worn.

The scroll plate is worn.

A normal bearing of the compressor

The bearing is worn seriously, it is damaged completely

A clean filter (on the suction pipe of the system)

The filter is blocked by impunity, the suction and exhaust of the compressor will be

The filter is blocked by impunity, the suction of the compressor will be abnormal

Troubleshooting 109

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

Pour out all of the oil from the compressor,

oil separator and gas-liquid separator

The oil is dirty

Check the filter between the ball

valve and the 4-way valve

The filter is blocked by impunity

Clean the filter screen with

nitrogen, or replace the filter

Replace the compressor which

has been damaged

Add clean oil to the new compressor,

and gas-liquid separator

Replace the oil separator and

gas-liquid separator

Weld the pipes, vacuum drying the

system and recharge refrigerant

Make sure all the wire connection is

OK, restart the system

The oil is clean

The filter is clean

Pour out some oil from each compressor;

check the quality of the oil

The oil is dirty

The oil is clean

Step 3: Replace the compressor

Note:

1. Before pouring out the oil, shake the compressor, oil separator and gas-liquid separator first, because

impunity may deposit at the bottom of the tank.

2. If the oil of one compressor is clean, there’s no need to check the oil of the other compressor. If the oil of one

compressor has gone bad, check the oil of the other compressor is necessary. If all the oil of an outdoor unit needs to be replaced, after adding oil to the compressors, the rest oil should be charged to the gas-liquid separator.

110 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

The discharge pipe is connected to the oil pool of the compressor by the inner oil balance pipe, add oil from the discharge pipe with a funnel

3. Add oil to the compressor from the discharge pipe.

4. The type of the oil is FVC-68D, make sure the type of the oil is right because different compressor need

different type of oil, if the type is wrong there will be various kinds of problems.

Troubleshooting 111

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

Yes

P9/H9: Fan module protection

The fan module is too hot for bad temperature

Make sure the fan module working in the normal temperature range

Some power wires or signal wires of fan module are loose

Well connect the power wires and signal wires

The fan motor is blocked or disabled

Clear away the block or replace the fan motor

Output voltage between P and N on fan module is abnormal*

Replace the power supply module

Fan module is disabled

Replace the fan module

No

Yes

1 Program input port

3 Fan motor U, V, W output port

5 PCB control signal input port

* The normal value of output voltage between P and N on fan

5

6

4 3 2

1

P

N

4.16 P9/H9: DC fan module protection

If the system display three times P9 protection in 60 minutes, the system will stop and display H9 error code. When the system displays H9 error code, the system can resume only by restarting the machine. At this time, malfunction should be disposed promptly to avoid further damage.

heat dissipation or high ambient

Fan module instruction

2 Power supply indicator lamp

4 Fault indicator lamp

6 Signal feedback port

module is DC 310V

112 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

Conditions

Fault indicator lamp of fan module

Power supply indicator lamp of fan module

Digital tube display

Malfunction analysis

Power on

Off

Quantity of IDU or ―0‖

Check the power supply circuit for fan module. Check whether there has power supply for lightning protection plate, whether the protective tube is broken, whether the voltage after rectification is normal, whether the bridge rectifier is broken.

Power on

Off

Flicker

Quantity of IDU or ―0‖

Power supply of fan module has problem, needs to replace the fan module.

When fan motor start

At first the lamp is on then the lamp is off

On

P9/H9

Check whether the drive port and signal feedback port is loose, whether the fan module and fan motor is installed firmly. If above conditions are all OK, it needs to replace the fan module.

When fan motor start

At first the lamp is on then the lamp flicker

On

P9/H9

Check whether the transformer in lightning protection plate Is open circuit, whether the relay is broken. If occurs above problem, it needs to replace the lightning protection plate.

Fan motor running several minutes

On

P9/H9

Check whether the capacity setting from dial switch is accordance with actual ODU capacity, whether the capacity from spot check is accordance with actual ODU capacity. If occurs above problem, it needs to adjust the capacity setting. If above conditions are both OK, it needs to replace the main control board.

P9 protection analysis

Troubleshooting 113

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

The screw between inverter module and radiating fin is loose

Outdoor main PCB is damaged

Replace the outdoor main PCB

PL/CL

Temperature sensor of main or disabled①.

Replace the sensor

Yes

No

Yes

Tighten the screw, make sure the inverter module is closed to the radiating fin

Yes

4.17 PL/C7: Temperature protection of main inverter module

When the temperature of inverter module is over 80oC, it will display PL protection. If the system display three times PL protection in 100 minutes, the system will stop and display C7 error code. When the system displays C7 error code, the system can resume only by restarting the machine.

inverter module is short circuit

1. How to check whether the temperature sensor is short circuit or disabled①:

Using a multi-meter to measure resistance, if the resistance is too small, the sensor is short circuit, if the resistance in certain temperature is not consistent with attached table 2, the sensor is disabled

114 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

Temperature

(℃)

Resistance

value (kΩ)

Temperature

(℃)

Resistance

value (kΩ)

Temperature

(℃)

Resistance

value (kΩ)

Temperature

(℃)

Resistance

value (kΩ)

-20

115.266

20

12.6431

60

2.35774

100

0.62973

-19

108.146

21

12.0561

61

2.27249

101

0.61148

-18

101.517

22

11.5

62

2.19073

102

0.59386

-17

96.3423

23

10.9731

63

2.11241

103

0.57683

-16

89.5865

24

10.4736

64

2.03732

104

0.56038

-15

84.219

25

10

65

1.96532

105

0.54448

-14

79.311

26

9.55074

66

1.89627

106

0.52912

-13

74.536

27

9.12445

67

1.83003

107

0.51426

-12

70.1698

28

8.71983

68

1.76647

108

0.49989

-11

66.0898

29

8.33566

69

1.70547

109

0.486

-10

62.2756

30

7.97078

70

1.64691

110

0.47256

-9

58.7079

31

7.62411

71

1.59068

111

0.45957

-8

56.3694

32

7.29464

72

1.53668

112

0.44699

-7

52.2438

33

6.98142

73

1.48481

113

0.43482

-6

49.3161

34

6.68355

74

1.43498

114

0.42304

-5

46.5725

35

6.40021

75

1.38703

115

0.41164

-4

44

36

6.13059

76

1.34105

116

0.4006

-3

41.5878

37

5.87359

77

1.29078

117

0.38991

-2

39.8239

38

5.62961

78

1.25423

118

0.37956

-1

37.1988

39

5.39689

79

1.2133

119

0.36954

0

35.2024

40

5.17519

80

1.17393

120

0.35982

1

33.3269

41

4.96392

81

1.13604

121

0.35042

2

31.5635

42

4.76253

82

1.09958

122

0.3413

3

29.9058

43

4.5705

83

1.06448

123

0.33246

4

28.3459

44

4.38736

84

1.03069

124

0.3239

5

26.8778

45

4.21263

85

0.99815

125

0.31559

6

25.4954

46

4.04589

86

0.96681

126

0.30754

7

24.1932

47

3.88673

87

0.93662

127

0.29974

8

22.5662

48

3.73476

88

0.90753

128

0.29216

9

21.8094

49

3.58962

89

0.8795

129

0.28482

10

20.7184

50

3.45097

90

0.85248

130

0.2777

11

19.6891

51

3.31847

91

0.82643

131

0.27078

12

18.7177

52

3.19183

92

0.80132

132

0.26408

13

17.8005

53

3.07075

93

0.77709

133

0.25757

14

16.9341

54

2.95896

94

0.75373

134

0.25125

15

16.1156

55

2.84421

95

0.73119

135

0.24512

16

15.3418

56

2.73823

96

0.70944

136

0.23916

17

14.6181

57

2.63682

97

0.68844

137

0.23338

18

13.918

58

2.53973

98

0.66818

138

0.22776

19

13.2631

59

2.44677

99

0.64862

139

0.22231

Attached table 1: Resistance value of ambient temperature and pipe temperature sensor

Troubleshooting 115

R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz MCAC-VTSM-2015-02

Temperature

(℃)

Resistance

value (kΩ)

Temperature

(℃)

Resistance

value (kΩ)

Temperature

(℃)

Resistance

value (kΩ)

Temperature

(℃)

Resistance value

(kΩ)

-20

542.7

20

68.66

60

13.59

100

3.702

-19

511.9

21

65.62

61

13.11

101

3.595

-18

483

22

62.73

62

12.65

102

3.492

-17

455.9

23

59.98

63

12.21

103

3.392

-16

430.5

24

57.37

64

11.79

104

3.296

-15

406.7

25

54.89

65

11.38

105

3.203

-14

384.3

26

52.53

66

10.99

106

3.113

-13

363.3

27

50.28

67

10.61

107

3.025

-12

343.6

28

48.14

68

10.25

108

2.941

-11

325.1

29

46.11

69

9.902

109

2.86

-10

307.7

30

44.17

70

9.569

110

2.781

-9

291.3

31

42.33

71

9.248

111

2.704

-8

275.9

32

40.57

72

8.94

112

2.63

-7

261.4

33

38.89

73

8.643

113

2.559

-6

247.8

34

37.3

74

8.358

114

2.489

-5

234.9

35

35.78

75

8.084

115

2.422

-4

222.8

36

34.32

76

7.82

116

2.357

-3

211.4

37

32.94

77

7.566

117

2.294

-2

200.7

38

31.62

78

7.321

118

2.233

-1

190.5

39

30.36

79

7.086

119

2.174

0

180.9

40

29.15

80

6.859

120

2.117

1

171.9

41

28

81

6.641

121

2.061

2

163.3

42

26.9

82

6.43

122

2.007

3

155.2

43

25.86

83

6.228

123

1.955

4

147.6

44

24.85

84

6.033

124

1.905

5

140.4

45

23.89

85

5.844

125

1.856

6

133.5

46

22.89

86

5.663

126

1.808

7

127.1

47

22.1

87

5.488

127

1.762

8

121

48

21.26

88

5.32

128

1.717

9

115.2

49

20.46

89

5.157

129

1.674

10

109.8

50

19.69

90 5 130

1.632

11

104.6

51

18.96

91

4.849

12

99.69

52

18.26

92

4.703

13

95.05

53

17.58

93

4.562

14

90.66

54

16.94

94

4.426

15

86.49

55

16.32

95

4.294

B(25/50)=3950K

16

82.54

56

15.73

96

4.167

17

78.79

57

15.16

97

4.045

R(90℃)=5KΩ+-3%

18

75.24

58

14.62

98

3.927

19

71.86

59

14.09

99

3.812

Attached table 2: Resistance value of compressor discharge temperature sensor

116 Troubleshooting

MCAC-VTSM-2015-02 R410A DC Inverter VRF V4 Plus Individual Series Side Discharge Type 50Hz

Ambient temperature (T4)

℃

20-27

27-33

33-38

38-45

Discharge pressure (spot check)

MPa

2.1-2.3

2.8-3.1

3.3-3.5

3.7-3.9

Pressure of high pressure valve

MPa

1.8-2.0

2.4-2.7

2.8-3.0

3.2-3.5

Pressure of low pressure valve

MPa

0.7-0.9

0.8-1.0

1.0-1.2

1.2-1.4

Discharge temperature (spot check)

℃

50-65

70-85

70-90

80-90

DC Inverter compressor current (spot check)

A

4-5

6-7

7-8

9-11

Fixed compressor current (spot check)

A

6-7

8-9

9-11

11-12

Average temperature of evaporator outlet T2B

℃

8-9

12-15

16-17

20

Ambient temperature (T4)

℃

-15--5

-5-5

5-12

12-18

Discharge pressure (spot check)

MPa

2.0-2.2

2.2-2.7

3.0-3.1

2.6-2.7

Pressure of high pressure valve

MPa

1.7-1.8

1.8-2.4

2.6-2.8

2.1-2.4

Pressure of low pressure valve

MPa

2.0-2.2

2.2-2.6

3.0-3.1

2.5-2.7

Discharge temperature (spot check)

℃

50-70

60-70

60-85

60-70

DC Inverter compressor current (spot check)

A 5 5-6

6-8

5-6

Fixed compressor current (spot check)

A 6 6-7

9-10

8-9

Average temperature of condenser outlet T2

℃

33

33-40

46-50

39-41

Attached table 3: Commissioning and operating parameters of refrigerant system

Conditions 1: Make sure outdoor unit can detect all the indoor units, the quantity of indoor units display steadily and be equal to

actual quantity of installed indoor units.

Conditions 2: Make sure all the valves in outdoor unit are open, indoor units EXV have connected to indoor PCB. Conditions 3: The ratio of connectable indoor units is 100%. When ambient temperature is high, operate the system in cooling

mode and set the temperature 17℃. When ambient temperature is low, operate the system in heating mode and set the temperature 30℃. Then get the parameters after system running normally more than 30 minutes.

Outdoor unit cooling parameters table

Outdoor unit heating parameters table

Troubleshooting 117