Troubleshooting Check Table - Mitsubishi Electric MUZ-EF25VE - E1 Service Manual

11-3. TROUBLESHOOTING CHECK TABLE

No. Symptom LED indication
Outdoor unit 1-time fl ash every
does not op- 2.5 seconds
1 erate.
2
3
6-time fl ash
4
2.5 seconds OFF
11-time fl ash
5
2.5 seconds OFF
14-time fl ash
2.5 seconds OFF
6
16-time fl ash
7 2.5 seconds OFF
'Outdoor unit 2-time fl ash
stops and 2.5 seconds OFF
8
restarts 3
minutes later'
is repeated.
3-time fl ash
2.5 seconds OFF
9
4-time fl ash
2.5 seconds OFF
10
5-time fl ash
11 2.5 seconds OFF
8-time fl ash
12 2.5 seconds OFF
10-time fl ash
2.5 seconds OFF
13
12-time fl ash
14
2.5 seconds OFF
13-time fl ash
15
2.5 seconds OFF
Outdoor unit 1-time fl ash
16
operates. 2.5 seconds OFF
3-time fl ash
2.5 seconds OFF
17
4-time fl ash
2.5 seconds OFF
18
5-time fl ash
19 2.5 seconds OFF
Outdoor unit 7-time fl ash
20 operates. 2.5 seconds OFF
8-time fl ash
2.5 seconds OFF
21
9-time fl ash
2.5 seconds OFF
22
NOTE: 1. The location of LED is illustrated at the right fi gure. Refer to 11-6.1.
2. LED is lighted during normal operation.
The fl ashing frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the fl ashing frequency is "2".
ON
2.5-second OFF
OFF
OBH590B
Abnormal point/
Condition
Outdoor power sys- Overcurrent protection cut-out operates 3 consecutive times
tem within 1 minute after the compressor gets started.
Outdoor thermistors Discharge temperature thermistor, fi n 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.
Outdoor control sys- Nonvolatile memory data cannot be read properly.
tem
(The left lamp of OPERATION INDICATOR lamp of the indoor
unit lights up or fl ashes 7-time.)
Serial signal The communication fails between the indoor and outdoor unit
for 3 minutes.
Stop valve/ Closed valve is detected by compressor current.
Closed valve
Outdoor unit Outdoor unit is defective.
(Other abnormality)
4-way valve/ The 4-way valve does not work properly.
Pipe temperature The indoor coil thermistor detects an abnormal temperature.
Overcurrent protec- Large current fl ows into intelligent power module.
tion
Discharge tempera- Temperature of discharge temperature thermistor exceeds
ture overheat pro- 116°C, compressor stops. Compressor can restart if discharge
tection temperature thermistor reads 100°C or less 3 minutes later.
Fin temperature Temperature of fi n temperature thermistor on the heat sink
/P.C. board tem- exceeds 75 ~ 86°C or temperature of P.C. board temperature
perature thermistor thermistor on the inverter P.C.board exceeds 72 ~ 85°C.
overheat protection
High pressure pro- Indoor coil thermistor exceeds 70°C in HEAT mode. Defrost
tection thermistor exceeds 70°C in COOL mode.
Compressor syn- The waveform of compressor current is distorted.
chronous abnormal-
ity
Outdoor fan motor Outdoor fan has stopped 3 times in a row within 30 seconds
after outdoor fan start-up.
Each phase current
Each phase current of compressor cannot be detected nor-
of compressor mally.
DC voltage DC voltage of inverter cannot be detected normally.
Frequency drop by When the input current exceeds approximately 7A(EF25)/
current protection 8A(EF35)/9A(EF42)/12A(EF50), compressor frequency lowers.
Frequency drop by Temperature of indoor coil thermistor exceeds 55°C in HEAT
high pressure pro- mode, compressor frequency lowers.
tection
Frequency drop by Indoor coil thermistor reads 8°C or less in COOL mode, com-
defrosting in COOL pressor frequency lowers.
mode
Frequency drop by Temperature of discharge temperature thermistor exceeds
discharge tempera- 111°C, compressor frequency lowers.
ture protection
Outside temperature When the outside temperature thermistor shorts or opens,
thermistor protec- protective operation without that thermistor is performed.
tion
Low discharge tem- Temperature of discharge temperature thermistor has been
perature protection 50°C or less for 20 minutes.
PAM protection The overcurrent fl ows into PFC (Power factor correction :
PAM: Pulse Ampli- IC820) or the bus-bar voltage reaches 394 V or more, PAM
tude Modulation stops and restarts.
Inverter check mode The connector of compressor is disconnected, inverter check
mode starts.
0.5-second ON
2.5-second OFF
Condition
0.5-second ON
33
Remedy
• Reconnect connector of compres-
sor.
• Refer to 11-5. "How to check in-
verter/compressor".
• Check stop valve.
• Refer to 11-5. "Check of outdoor
thermistors".
• Replace inverter P.C. board.
• Refer to 11-5. "How to check
miswiring and serial signal error.
• Check stop valve.
• Refer to 11-2.2. "Flow chart of the
detailed outdoor unit failure mode
recall function".
• Refer to 11-5. "Check of R.V.
coil".
• Replace inverter P.C. board.
• Reconnect connector of compressor.
• Refer to 11-5. "How to check in-
verter/compressor".
• Check stop valve.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-5. "Check of LEV".
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 11-5. "Check of outdoor
fan motor".
• Check refrigerant circuit and refrig-
erant amount.
• Check stop valve.
• Reconnect connector of compressor.
• Refer to 11-5. "How to check in-
verter/compressor".
• Refer to 11-5. "Check of outdoor
fan motor.
• Refer to 11-5. "Check of inverter
P.C. board.
• Refer to 11-5. "How to check in-
verter/compressor".
• Refer to 11-5. "How to check in-
verter/compressor".
The unit is normal, but check the
following.
• Check if indoor fi lters are clogged.
• Check if refrigerant is short.
• Check if indoor/outdoor unit air
circulation is short cycled.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 11-5. "Check of LEV".
• Refer to 11-5. "Check of outdoor
thermistors".
• Refer to 11-5. Check of outdoor
thermistors.
• Refer to 11-5. "Check of LEV".
• Check refrigerant circuit and refrig-
erant amount.
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.
• Check if the connector of the com-
pressor is correctly connected.
Refer to 11-5. "How to check
inverter/compressor".
Inverter P.C. board
Flashing →
LED