Mitsubishi Electronics MUZ-FD09NA service manual Troubleshooting Check Table

Page 20

10-3. TROUBLESHOOTING CHECK TABLE

No.

Symptom

LED indication

Abnormal point/

Condition

Correspondence

Condition

 

 

 

 

 

 

 

Outdoor unit

1-time flash every

Outdoor power sys-

Overcurrent protection stop is continuously performed 3 times

•Reconnect connector of compres-

1

does not oper-

2.5 seconds

tem

within 1 minute after the compressor gets started, or failure of

sor.

 

ate.

 

 

restart of compressor has repeated 24 times.

•Refer to 10-5. "How to check in-

 

 

 

 

 

verter/ compressor".

 

 

 

 

 

•Check stop valve.

 

 

 

Outdoor thermistors

Discharge temperature thermistor, fin temperature thermistor,

•Refer to 10-5. "Check of outdoor

2

 

 

 

defrost thermistor, P.C. board temperature thermistor or ambi-

thermistors".

 

 

 

 

ent temperature thermistor shorts or opens during compressor

 

 

 

 

 

 

running.

 

 

3

 

 

Outdoor control sys-

Nonvolatile memory data cannot be read properly.

•Replace inverter P.C. board.

 

 

tem

(POWER lamp of the indoor unit lights up or flashes 7-time.)

 

 

 

 

 

 

 

 

4

 

6-time flash

Serial signal

The communication fails between the indoor and outdoor unit

•Refer to 10-5.

"How to check

 

2.5 seconds OFF

 

for 3 minutes.

miswiring and serial signal error.

 

 

 

5

 

11-time flash

Stop valve/

Closed valve is detected by compressor current.

•Check stop valve.

 

2.5 seconds OFF

Closed valve

 

 

 

 

 

 

 

 

 

 

14-time flash

Outdoor unit

Outdoor unit is defective.

•Refer to 10-2.2. "Flow chart of the

6

 

2.5 seconds OFF

(Other abnormality)

 

detailed outdoor unit failure mode

 

 

 

 

 

recall function".

 

 

'Outdoor unit

2-time flash

Overcurrent protec-

Large current flows into intelligent power module.

•Reconnect connector of compres-

7

stops and

2.5 seconds OFF

tion

When overcurrent protection occurs within 10 seconds after

sor.

 

restarts 3 min-

 

 

compressor starts, compressor restarts after 15 seconds.

•Refer to 10-5. "How to check in-

 

utes later' is

 

 

 

verter/compressor".

 

repeated.

 

 

 

•Check stop valve.

 

 

3-time flash

Discharge tempera-

Temperature of discharge temperature thermistor exceeds 241

•Check refrigerant circuit and refrig-

8

 

2.5 seconds OFF

ture overheat protec-

°F (116 °C), compressor stops. Compressor can restart if dis-

erant amount.

 

 

 

tion

charge temperature thermistor reads 212 °F (100 °C) or less 3

•Refer to 10-5.

"Check of LEV".

 

 

 

 

minutes later.

 

 

 

 

4-time flash

Fin temperature /P.C.

Temperature of fin temperature thermistor on the heat sink ex-

•Check around outdoor unit.

 

 

2.5 seconds OFF

board temperature

ceeds 167 ~ 176 °F (75 ~ 80 °C) or temperature of P.C. board

•Check outdoor unit air passage.

9

 

 

thermistor overheat

temperature thermistor on the inverter P.C. board exceeds 158

•Refer to 10-5. "Check of outdoor

 

 

 

protection

~ 167 °F (70 ~ 75 °C).

fan motor".

 

 

 

 

 

 

 

10

 

5-time flash

High pressure pro-

Indoor coil thermistor exceeds 158 °F (70 °C) in HEAT mode.

•Check refrigerant circuit and refrig-

 

2.5 seconds OFF

tection

Defrost thermistor exceeds 158 °F (70 °C) in COOL mode.

erant amount.

 

 

 

 

 

 

•Check stop valve.

 

 

8-time flash

Compressor syn-

The waveform of compressor current is distorted.

•Reconnect connector of compres-

11

 

2.5 seconds OFF

chronous abnormal-

 

sor.

 

 

 

ity

 

•Refer to 10-5. "How to check in-

 

 

 

 

 

verter/compressor".

 

 

10-time flash

Outdoor fan motor

Outdoor fan has stopped 3 times in a row within 30 seconds

•Refer to 10-5. "Check of outdoor

12

 

2.5 seconds OFF

 

after outdoor fan start-up.

fan motor.

 

 

 

 

 

•Refer to 10-5. "Check of inverter

 

 

 

 

 

P.C. board.

 

13

 

12-time flash

Each phase current

Each phase current of compressor cannot be detected nor-

•Refer to 10-5.

"How to check in-

 

2.5 seconds OFF

of compressor

mally

verter/compressor".

 

 

14

 

13-time flash

DC voltage

DC voltage of inverter cannot be detected normally.

•Refer to 10-5.

"How to check in-

 

2.5 seconds OFF

 

 

verter/compressor".

 

 

 

 

15

Outdoor unit

1-time flash

Frequency drop by

Current from power outlet reaches the protection current, and

The unit is normal, but check the

operates.

2.5 seconds OFF

current protection

compressor frequency lowers.

following.

 

 

 

 

 

 

•Check if indoor filters are clogged.

 

 

3-time flash

Frequency drop by

Temperature of indoor coil thermistor exceeds 131 °F (55 °C)

 

 

•Check if refrigerant is short.

 

 

2.5 seconds OFF

high pressure pro-

in HEAT mode, compressor frequency lowers.

 

 

•Check if indoor/outdoor unit air cir-

 

 

 

tection

 

16

 

 

 

culation is short cycled.

 

 

Frequency drop by

Indoor coil thermistor reads 46 °F (8 °C) or less in COOL

 

 

 

 

 

 

 

 

defrosting in COOL

mode, compressor frequency lowers.

 

 

 

 

 

mode

 

 

 

 

 

4-time flash

Frequency drop by

Temperature of discharge temperature thermistor exceeds 232

•Check refrigerant circuit and refrig-

17

 

2.5 seconds OFF

discharge tempera-

°F (111 °C), compressor frequency lowers.

erant amount.

"Check of LEV".

 

 

ture protection

 

•Refer to 10-5.

 

 

 

 

 

•Refer to 10-5. "Check of outdoor

 

 

 

 

 

thermistors".

 

NOTE: 1. The location of LED is illustrated at the right figure. Refer to 10-6.1. 2. LED is lighted during normal operation.

The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF. Flashing (Example) When the flashing frequency is “2”.

Inverter P.C. board(Parts side)

LED

Flashing →

ON

OFF

2.5-second OFF

0.5-second ON

0.5-second ON

2.5-second OFF

20

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Contents MUZ-FD09NA MUZ-FD09NA- U1 MUZ-FD12NA MUZ-FD12NA- U1 Page Technical Changes Part Names and FunctionsSpecification MUZ-FD09NA MUZ-FD12NATest condition Operating RangeOutlines and Dimensions Required SpaceWiring Diagram Refrigerant System Diagram MAX. Refrigerant Piping Length and MAX. Height DifferenceData Performance Curve Cooling MUZ-FD09NA MUZ-FD12NAHeating MUZ-FD09NACondensing Pressure Cooling Condensing pressure65 70F Standard Operation Data MSZ-FD09NA MSZ-FD12NATest RUN Operation How to operate fixed-frequency operation Correction of Heating capacityActuator Control Outdoor FAN Motor ControlR.V. Coil Control Relation Between Main Sensor and ActuatorService Functions TroubleshootingChange in Defrost Setting PRE-HEAT Control SettingFailure Mode Recall Function OFFOperational procedure Outdoor unit failure mode table Troubleshooting Check Table Page Trouble Criterion of Main Parts MUZ-FD09NAMUZ-FD12NA WHT REDHow to check inverter/ compressor Check of open phaseTroubleshooting Flow Check of compressorCheck of compressor start failure Check of compressor windingCheck of compressor operation time Unit operates Cool mode even if it is set to Heat mode Unit operates Heat mode even if it is set to Cool modeCheck of outdoor thermistors Check of R.V. coilCheck of power supply Check of outdoor fan motorCheck of LEV Expansion valve Check of inverter P.C. board Emergency OperationPage Electromagnetic noise enters into TV sets or radios Outdoor unitTest Point Diagram and Voltage Inverter P.C. boardDisassembly Instructions Removing the cabinet PhotoRemoving the inverter assembly, inverter P.C. board Photo Photo 4 inverter assemblyPhoto Removing the discharge temperature thermistor Removing R.V. coilRemoving outdoor fan motor Photo Removing the compressor and 4-way valvePage New publication, effective Jan
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MUZ-FD09NA specifications

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