12-2. FAILURE MODE RECALL FUNCTION
2. Flow chart of the detailed outdoor unit failure mode recall function
Does the left OPERATION INDICATOR lamp on the indoor unit blink at the interval of 0.5 seconds?
Blinks: The outdoor unit is abnormal. Beep is emitted at the same timing as the blinking of the left lamp on the indoor unit. 2
Yes (Blinks)
No (OFF) The outdoor unit might be abnormal.
Check if outdoor unit is abnormal according to the following procedures.
Operational procedure
Make sure that the remote controller is set to the failure mode recall function.
With the remote controller headed towards the indoor unit, press TEMP button to adjust the set temperature to 25°C. 1
1. Regardless of normal or abnormal condition, 2 short beeps are emitted as the signal is received.
The outdoor unit is abnormal.
Check the blinking pattern, and identify the abnormal point by referring to the table of outdoor unit failure mode recall function (12-2.3.).
Make sure to check at least 2 consecutive blinking cycles. 2
Releasing the failure mode recall function
Release the failure mode recall function by the following procedures.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.
Repair the failure parts.
The outdoor unit is normal.
Release the failure mode recall function accord- ing to the left mentioned procedure.
Deleting the memorized abnormal condition
After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall func- tion" (12-2.1.).
Press OFF/ON (stop/operate) button of the remote controller (the set temperature is displayed) with the remote controller headed towards the indoor unit.
Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted. 3 Release the failure mode recall function according to "Releasing the failure mode recall function" men-
tioned above.
NOTE: 1. Make sure to release the failure mode recall function after it is set up, otherwise the unit cannot operate properly.
2. If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.
3 The information regarding whether the connected outdoor unit is a low-standby-
power model or a non-low-standby-power model will also be initialized.
(Default= compatible with a low-standby- power model)
NOTE: It takes up to 1 minute to indicate the outdoor unit abnor- mality.
Even if the left lamp on the indoor unit is not lighting, keep checking at least 1 minute or longer.
33 3. Table of outdoor unit failure mode recall function
NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (12-3.).
Left OPERTAION INDICATOR lamp (Indoor unit)
Abnormal point (Failure mode/protection)
LED indication
(Outdoor P.C. board) Condition Remedy
Indoor/outdoor unit failure mode recall
function
Outdoor unit failure mode recall function
OFF None (Normal) — — — — —
1-time blink 2.5 seconds OFF
Indoor/outdoor communication, receiving error
—
Any signals from the inverter P.C.
board cannot be received normally for 3 minutes.
•Refer to 12-5. How to check miswiring and serial signal error.
○ ○
Indoor/outdoor communication, receiving error
—
Although the inverter P.C. board sends signal "0", signal "1" has been received 30 consecutive times.
•Refer to 12-5. How to check miswiring and serial signal error.
2-time blink 2.5 seconds OFF
Outdoor power system
—
Overcurrent protection cut-out operates 3 consecutive times within 1 minute after the compressor gets started.
• Reconnect connectors.
• Refer to 12-5. "How to check inverter/
compressor".
• Check stop valve.
○ ○
3-time blink 2.5 seconds OFF
Discharge temperature thermistor
1-time blink every 2.5 seconds
Thermistor shorts or opens during
compressor running. • Refer to 12-5.
"Check of outdoor thermistors".
Defective outdoor thermistors can be identified by checking the blinking pattern of
LED.
○ ○
Defrost thermistor
Fin temperature thermistor 3-time blink 2.5 seconds OFF P.C. board temperature
thermistor
4-time blink 2.5 seconds OFF Ambient temperature
thermistor
2-time blink 2.5 seconds OFF Outdoor heat exchanger
temperature thermistor —
4-time blink 2.5 seconds OFF
Overcurrent 11-time blink
2.5 seconds OFF
Large current flows into power module (IC700).
• Reconnect
compressor connector.
• Refer to 12-5. "How to check inverter/
compressor".
• Check stop valve.
—
○
Compressor synchronous abnormality (Compressor start-up failure protection)
12-time blink 2.5 seconds OFF
Waveform of compressor current is distorted.
• Reconnect
compressor connector.
• Refer to 12-5. "How to check inverter/
compressor".
—
○
5-time blink 2.5 seconds OFF
Discharge temperature
—
Temperature of discharge temperature thermistor exceeds 116°C, compressor stops.
Compressor can restart if discharge temperature thermistor reads 100°C or less 3 minutes later.
• Check refrigerant circuit and refrigerant amount.
• Refer to 12-5. "Check of LEV".
—
○
6-time blink 2.5 seconds OFF
High pressure
—
Temperature of indoor coil thermistor exceeds 70°C in HEAT mode.
Temperature of defrost thermistor exceeds 70°C in COOL mode.
• Check refrigerant circuit and refrigerant amount.
• Check stop valve.
—
○
7-time blink 2.5 seconds OFF
Fin temperature/P.C. board temperature
7-time blink 2.5 seconds OFF
Temperature of fin temperature thermistor on the inverter P.C. board exceeds 75
~ 86°C, or temperature of P.C. board temperature thermistor on the inverter P.C.
board exceeds 72 ~ 85°C.
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 12-5. "Check of outdoor fan motor".
—
○
8-time blink 2.5 seconds OFF
Outdoor fan motor
—
Outdoor fan has stopped 3 times in a row within 30 seconds after outdoor fan startup.
• Refer to 12-5. "Check of outdoor fan motor".
Refer to 12-5. "Check of inverter P.C. board".
—
○
9-time blink 2.5 seconds OFF
Nonvolatile memory data 5-time blink 2.5 seconds OFF
Nonvolatile memory data cannot be read properly.
• Replace the inverter
P.C. board.
○ ○
Power module (IC700) 6-time blink 2.5 seconds OFF
The interface short circuit occurs in the output of the power module (IC700).
The compressor winding shorts circuit.
• Refer to 12-5. "How to check inverter/
compressor".
—
NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (12-3.).
Left OPETATION INDICATOR lamp (Indoor unit)
Abnormal point (Failure mode/protection)
LED indication
(Outdoor P.C. board) Condition Remedy
Indoor/outdoor unit failure mode recall
function
Outdoor unit failure mode recall function 10-time blink
2.5 seconds OFF
Discharge temperature
—
Temperature of discharge temperature thermistor has been 50°C or less for 20 minutes.
• Refer to 12-5. "Check of LEV".
• Check refrigerant circuit and refrigerant amount.
—
○
11-time blink 2.5 seconds OFF
Bus-bar voltage (DC) 8-time blink 2.5 seconds OFF
Bus-bar voltage of inverter cannot be detected normally.
• Refer to 12-5. "How to check inverter/
compressor". —
○
Each phase current of compressor
9-time blink 2.5 seconds OFF
Each phase current of compressor cannot be detected normally.
14-time blink 2.5 seconds OFF
Stop valve (Closed valve) 14-time blink 2.5 seconds OFF
Closed valve is detected by compressor current.
• Check stop valve.
○ ○
4-way valve/
Pipe temperature
16-time blink 2.5 seconds OFF
The 4-way valve does not work properly.
The indoor coil thermistor detects an abnormal temperature.
• Check the 4-way valve.
• Replace the inverter P.C. board.
16-time blink 2.5 seconds OFF
Outdoor refrigerant system abnormality
1-time blink 2.5 seconds OFF
A closed valve and air trapped in the refrigerant circuit are detected based on the temperature sensed by the indoor and outdoor thermistors and the current of the compressor.
• Check for a gas leak in a connecting piping etc.
• Check the stop valve.
• Refer to 12-5.
“Check of outdoor refrigerant circuit”.
○ ○
35
12-3. TROUBLESHOOTING CHECK TABLE
No. Symptom LED indication Abnormal point/ Con-
dition Condition Remedy
1
Outdoor unit does not op- erate.
1-time blink every 2.5 seconds
Outdoor power sys- tem
Overcurrent protection cut-out operates 3 consecutive times
within 1 minute after the compressor gets started. • Reconnect connector of compres- sor.
• Refer to 12-5. "How to check inverter/compressor".
• Check stop valve.
2
Outdoor thermistors Discharge temperature thermistor, fin temperature thermistor, defrost thermistor, P.C. board temperature thermistor, outdoor heat exchanger temperature thermistor or ambient tempera- ture thermistor shorts or opens during compressor running.
• Refer to 12-5. "Check of outdoor thermistors".
3
Outdoor control sys- tem
Nonvolatile memory data cannot be read properly.
(The left OPERATION INDICATOR lamp on the indoor unit lights up or blinks 7-time.)
• Replace inverter P.C. board.
4 6-time blink
2.5 seconds OFF
Serial signal The communication fails between the indoor and outdoor unit
for 3 minutes. • Refer to 12-5. "How to check
miswiring and serial signal error.
5 11-time blink
2.5 seconds OFF
Stop valve/
Closed valve
Closed valve is detected by compressor current. • Check stop valve.
6
14-time blink 2.5 seconds OFF
Outdoor unit (Other abnormality)
Outdoor unit is defective. • Refer to 12-2.2. "Flow chart of the detailed outdoor unit failure mode recall function".
7
16-time blink
2.5 seconds OFF 4-way valve/
Pipe temperature The 4-way valve does not work properly.
The indoor coil thermistor detects an abnormal temperature. • Refer to 12-5. "Check of R.V.
coil".
• Replace the inverter P.C. board.
8
17-time blink 2.5 seconds OFF
Outdoor refrigerant system abnormality
A closed valve and air trapped in the refrigerant circuit are detected based on the temperature sensed by the indoor and outdoor thermistors and the current of the compressor.
• Check for a gas leak in a connecting piping etc.
• Check the stop valve.
• Refer to 12-5. “Check of outdoor refrigerant circuit”.
9
'Outdoor unit stops and restarts 3 minutes later' is repeated.
2-time blink 2.5 seconds OFF
Overcurrent protec-
tion Large current flows into power module (IC700). • Reconnect connector of compressor.
• Refer to 12-5. "How to check inverter/compressor".
• Check stop valve.
10
3-time blink 2.5 seconds OFF
Discharge tem- perature overheat protection
Temperature of discharge temperature thermistor exceeds 116°C, compressor stops. Compressor can restart if discharge temperature thermistor reads 100°C or less 3 minutes later.
• Check refrigerant circuit and refrig- erant amount.
• Refer to 12-5. "Check of LEV".
11
4-time blink 2.5 seconds OFF
Fin temperature / P.C. board tem- perature thermistor overheat protection
Temperature of fin temperature thermistor on the heat sink exceeds 75 ~ 86°C or temperature of P.C. board temperature thermistor on the inverter P.C. board exceeds 72 ~ 85°C.
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 12-5. "Check of outdoor fan motor".
12
5-time blink 2.5 seconds OFF
High pressure pro- tection
Indoor coil thermistor exceeds 70°C in HEAT mode. Defrost
thermistor exceeds 70°C in COOL mode. • Check refrigerant circuit and refrig- erant amount.
• Check stop valve.
13
8-time blink 2.5 seconds OFF
Compressor syn- chronous abnormal- ity
The waveform of compressor current is distorted. • Reconnect connector of compressor.
• Refer to 12-5. "How to check inverter/compressor".
14
10-time blink 2.5 seconds OFF
Outdoor fan motor Outdoor fan has stopped 3 times in a row within 30 seconds
after outdoor fan start-up. • Refer to 12-5. "Check of outdoor fan motor.
• Refer to 12-5. "Check of inverter P.C. board.
15 12-time blink
2.5 seconds OFF
Each phase current
of compressor Each phase current of compressor cannot be detected nor-
mally. • Refer to 12-5. "How to check
inverter/compressor".
16
13-time blink 2.5 seconds OFF
Bus-bar voltage (DC)
Bus-bar voltage of inverter cannot be detected normally. • It occurs with following case.
Instantaneous power voltage drop.
(Short time power failure)
• Refer to 12-5. "Check of power supply".
• Refer to 12-5. "How to check in- verter/compressor".
17 Outdoor unit operates.
1-time blink 2.5 seconds OFF
Frequency drop by current protection
When the input current exceeds approximately 10A, compres- sor frequency lowers.
The unit is normal, but check the following.
• Check if indoor filters are clogged.
• Check if refrigerant is short.
• Check if indoor/outdoor unit air circulation is short cycled.
18
3-time blink 2.5 seconds OFF
Frequency drop by high pressure pro- tection
Temperature of indoor coil thermistor exceeds 55°C in HEAT mode, compressor frequency lowers.
19
Frequency drop by defrosting in COOL mode
Indoor coil thermistor reads 8°C or less in COOL mode, com- pressor frequency lowers.
4-time blink 2.5 seconds OFF
Frequency drop by discharge tempera- ture protection
Temperature of discharge temperature thermistor exceeds
111°C, compressor frequency lowers. • Check refrigerant circuit and refrig- erant amount.
• Refer to 12-5. "Check of LEV".
• Refer to 12-5. "Check of outdoor thermistors".
20
5-time blink 2.5 seconds OFF
Outside temperature thermistor protec- tion
When the outside temperature thermistor shorts or opens,
protective operation without that thermistor is performed. • Refer to 12-5. Check of outdoor thermistors.
No. Symptom LED indication Abnormal point/ Con-
dition Condition Remedy
21
Outdoor unit operates.
7-time blink 2.5 seconds OFF
Low discharge tem- perature protection
Temperature of discharge temperature thermistor has been
50°C or less for 20 minutes. • Refer to 12-5. "Check of LEV".
• Check refrigerant circuit and refrig- erant amount.
22
8-time blink 2.5 seconds OFF
PAM protection PAM: Pulse Ampli- tude Modulation
The overcurrent flows into PFC (Power factor correction:
IC820) or the bus-bar voltage reaches 394 V or more, PAM stops and restarts.
This is not malfunction. PAM pro- tection will be activated in the fol- lowing cases:
1 Instantaneous power voltage drop. (Short time power failure) 2 When the power supply voltage
is high.
23
9-time blink 2.5 seconds OFF
Inverter check mode The connector of compressor is disconnected, inverter check
mode starts. • Check if the connector of the com-
pressor is correctly connected.
Refer to 12-5. "How to check inverter/compressor".
NOTE: 1. The location of LED is illustrated at the right figure. Refer to 12-6.1.
2. LED is lighted during normal operation.
The blinking frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the blinking frequency is “2”.
ON
OFF 2.5-second OFF 2.5-second OFF
0.5-second ON 0.5-second ON LED
Blinking → Inverter P.C. board
37
12-4. TROUBLE CRITERION OF MAIN PARTS
Part name Check method and criterion Figure
Defrost thermistor (RT61) Fin temperature
thermistor (RT64) Ambient temperature thermistor (RT65) Outdoor heat exchanger temperature thermistor (RT68)
Measure the resistance with a tester.
Refer to 12-6. “Test point diagram and voltage”, 1. “Inverter P.C.
board”, for the chart of thermistor.
Discharge temperature thermistor (RT62)
Measure the resistance with a tester. Before measurement, hold the thermistor with your hands to warm it up.
Refer to 12-6. “Test point diagram and voltage”, 1. “Inverter P.C.
board”, for the chart of thermistor.
Compressor
Measure the resistance between terminals using a tester.
(Temperature: -10 ~ 40°C)
Normal (Ω)
MUZ-BT20/25/35VG MUZ-BT50VG U-V
U-W V-W
1.59 ~ 2.16 0.82 ~ 1.11
W
V U
WHT RED BLK
Outdoor fan motor
Measure the resistance between lead wires using a tester.
(Temperature: -10 ~ 40°C)
Color of lead wire Normal (Ω)
MUZ-BT20/25/35VG MUZ-BT50VG RED – BLK
BLK – WHT WHT – RED
32 ~ 43 15 ~ 20
W
V U
WHT RED BLK
R. V. coil (21S4)
Measure the resistance using a tester. (Temperature: -10 ~ 40°C) Normal (kΩ)
1.41 ~ 2.00
Expansion valve coil (LEV)
Measure the resistance using a tester. (Temperature: -10 ~ 40°C) Color of lead wire Normal (Ω)
RED – ORN
37 ~ 54 RED – WHT
RED – BLU
RED – YLW
RED (+12V)
YLW BLU
WHT ORN
LEV