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Check of LEV

In document SERVICE MANUAL (сторінка 99-105)

No

Yes

No

Yes Turn ON the power supply to the outdoor unit after checking LEV coil is mounted to the LEV body securely.

Is "click - click" sound heard?

Or, do you feel vibration of LEV coil with your hand?

Disconnect the connectors.

CN791: LEV A, CN792: LEV B, CN793: LEV C, CN794: LEV D, CN795: LEV E, CN796: LEV F, CN797: LEV M.

Is there normal resistance to LEV coil?

(Refer to 11-5.)

Normal

Replace the inverter P.C. board, the

electronic control P.C. board, the control P.C.

board, or the outdoor control P.C. board.

Replace LEV coil.

• When cooling, heat exchanger of non-operating indoor unit frosts.

• When heating, non-operating indoor unit gets warm.

CN791 CN792 CN793 CN794 CN795 CN796 CN797

Control P.C. board MXZ-6C120 Electronic

control P.C. board MXZ-3C/

4C/5C MXZ-2C

Inverter P.C. board

MXZ-6C122 Outdoor control P.C. board

100

How to check inverter/compressor

• When cooling, room does not get cool.

Disconnect the terminal of the compressor or the connector (CNMC) between compressor and the inverter P.C. board/the outdoor power P.C. board. 3 minutes after turning ON the

power supply, start EMERGENCY OPERATION.

Is output balanced?

Clarify the causes by counting time until the inverter stops.

0 to 10 seconds: compressor layer short 10 to 60 seconds: compressor lock

60 seconds to 5minutes: refrigerant circuit defective 5 minutes or more: normal

Measure the voltage between each lead wire leading to the compressor.

U (BLK) - V (WHT) V (WHT) - W (RED) W (RED) - U (BLK) Output voltage 50V-250V

Is proper output voltage detected?

Turn OFF the power supply, and measure the compressor winding resistance between the compressor terminals.

Is there resistance between each terminal normal?

(Refer to 11-5.)

Is the input voltage to the electronic control P.C. board/the control P.C. board/the outdoor control P.C. board 370V or more (MXZ-3C/4C/

5C)/350V or more (MXZ-6C) ?

Reconnect the lead wire of compressor, and turn ON the power supply to indoor and outdoor unit.

3 minutes later, start EMERGENCY OPERATION.

Replace the compressor.

Replace the power board (MXZ-3C/4C/

5C/6C120)/outdoor power P.C. board (MXZ-6C122).

1 After the outdoor fan starts running, wait for 1 minute or more before measuring the voltage.

The output voltage values have the tolerance of ± 20%.

2 The output differs depending on the capacity or the number of indoor units to be operated.

No

1 2

No

Yes Yes

Yes

No

Yes

No Yes

(MXZ-2C)

(MXZ-3C/4C/5C/6C)

101

Check of outdoor thermistors

• When thermistor is abnormal.

Disconnect the connector in the following table and measure the resistance of the thermistor to check whether the thermistor is normal or not. (Refer to 11-7.)

Does the unit operate 10 minutes or more without showing thermistor abnormality?

Replace the thermistor except RT64.

In case that RT64 is abnormal, replace the inverter P.C. board or power board since RT64 is combined with the board.

Normal

Replace the inverter P.C. board, electronic control P.C. board, control P.C. board, outdoor control P.C. board, or the power board.

Normal

Yes

No

Abnormal

Reconnect the connector in the following table and disconnect the lead wire leading to the compressor.

3 minutes after turning ON the power supply, start EMERGENCY OPERATION.

Thermistor Defrost

Discharge temperature

Outdoor heat exchanger temperature Ambient temperature

Fin temperature

Symbol RT61RT62 RT68RT65 RT64

Connector, Pin No.

Between CN661 pin1 and pin2 Between CN661 pin3 and pin4 Between CN661 pin7 and pin8 Between CN663 pin1 and pin2 Between CN3 pin1 and pin2

Electronic control P.C. board Power board

Board MXZ-3C54/3C68/4C71/4C80/5C100VA MXZ-4C80/5C100VA2

Thermistor Defrost

Discharge temperature

Outdoor heat exchanger temperature Ambient temperature

Symbol RT61RT62 RT68RT65

Connector, Pin No.

Between CN661 pin1 and pin2 Between CN661 pin3 and pin4 Between CN661 pin5 and pin6 Between CN663 pin1 and pin2

Control P.C. board Board MXZ-6C120VA

Thermistor Defrost

Discharge temperature

Outdoor heat exchanger temperature Fin temperature

Ambient temperature

Symbol RT61RT62 RT68RT64 RT65

Connector, Pin No.

Between CN661 pin1 and pin2 Between CN661 pin3 and pin4 Between CN661 pin5 and pin6 Between CN662 pin1 and pin2 Between CN663 pin1 and pin2

Inverter P.C. board Board MXZ-2C30/2C40/2C52VA

Thermistor Defrost

Discharge temperature

Outdoor heat exchanger temperature Ambient temperature

Symbol RT61RT62 RT68RT65

Connector, Pin No.

Between CN661 pin1 and pin2 Between CN661 pin3 and pin4 Between CN661 pin5 and pin6 Between CN663 pin1 and pin2

Outdoor control P.C. board Board

MXZ-6C122VA

102

Check of outdoor fan motor

Yes

Yes No Yes

(Fixed to either 5V or 0V DC) No

No Disconnect CN932 and measure the resistance of the outdoor fan motor.

Turn ON the power supply.

Rotate the outdoor fan motor manually and measure the voltage of CN931.

Between (+) and (-) Between (+) and (-) Between (+) and (-) Is the resistance of outdoor fan motor

normal? (Refer to 11-5.)

Does the outdoor fan motor rotate smoothly?

Does the voltage between each terminal become 5V DC and 0V DC repeatedly?

Replace the outdoor fan motor. Replace the inverter P.C. board/electronic control P.C. board.

MXZ-2C30/2C40/2C52/3C54/3C68/4C71/4C80/5C100VA MXZ-4C80/5C100VA2

CN931

CN932 Electronic control P.C.

board

MXZ-2C MXZ-3C/4C/5C

Inverter P.C. board

103 No

Yes

No Yes

No Yes

No Yes

No Yes

Disconnect CN931 and measure the resistance of the outdoor fan motor.

Is the resistance of outdoor fan motor normal? (Refer to right table)

Turn on the power supply to start operation and measure the voltage of connector CN931.

Turn OFF the power supply and connect the connector CN931.

Turn ON the power supply and measure the voltage of connector CN931 while rotating the motor by the hand.

Does the outdoor fan motor rotate smoothly?

Replace the outdoor fan motor. Resistance

60 kΩ 160 kΩ Measuring points

* To measure the resistance, connect the negative (-) end of the tester to pin 4.

* To measure the voltage, connect the negative (-) end of the tester to pin 4.

* Voltage between pin 4 and 6 should be measured within 1 minute after the operation starts.

pin 1 - pin 4 pin 5 - pin 4 pin 6 - pin 4 pin 7 - pin 4 Voltage

15V DC 325 V DC 1 - 5V DC CN931

pin 1 - pin 4 pin 5 - pin 4 pin 6 - pin 4

Is the voltage of connector CN931 normal? (Refer to right table.)

Does the voltage between pin 7 and pin 4

of connector CN931 repeat 0V and 5V? Replace the outdoor fan motor.

Does the fan motor operate for about

5 seconds? Replace the outdoor fan motor.

Replace the outdoor fan motor.

Start operation.

Replace the control P.C. board or outdoor control P.C. board.

Replace the control P.C. board or outdoor control P.C. board.

MXZ-6C120/6C122VA

CN931 Control P.C.

board MXZ-6C120

Outdoor control P.C. board

MXZ-6C122

104

Check of HPS

Infinity 0Ω

Yes

No

1. Disconnect the connector CN681.

2. Check the resistance of HPS 1 minute after the outdoor unit power supply was turned OFF.

Check the resistance between each terminal.

Reconnect CN681.

Turn ON the power supply to the indoor and outdoor units.

3 minutes later, start EMERGENCY OPERATION.

Is HPS protection displayed immediately after compressor starts?

Replace HPS.

Replace the electronic control P.C. board, control P.C. board or the outdoor control P.C. board.

Normal

MXZ-3C68/4C71/4C80/5C100/6C120/6C122VA MXZ-4C80/5C100VA2

MXZ-3C/4C/5C MXZ-6C120 MXZ-6C1222 CN681 Electronic control P.C. board Control P.C. board

Outdoor control P.C. board

105

The other cases

Indoor unit does not operate. (different operating models in multi system)

• When you try to run two indoor units simultaneously, one for cooling and the other for heating, the unit which transmits signal to the outdoor unit first decides the operation mode.

• When the above situation occurs, set all the indoor units to the same mode, turn OFF the indoor units, then turn them back ON.

• Though the top of the indoor unit sometimes gets warm, this does not mean malfunction. The reason is that the refrigerant gas continuously flows into the indoor unit even while it is not operating.

In document SERVICE MANUAL (сторінка 99-105)