Mitsubishi Electric MUZ-AP25VG-E1 Service Manual page 60

No. Symptom LED indication
Outdoor unit 1-time blink
operates. 2.5 seconds OFF
17
3-time blink
2.5 seconds OFF
18
19
4-time blink
2.5 seconds OFF
MUZ-AP25/35/42
5-time blink
20
2.5 seconds OFF
Outdoor unit 7-time blink
operates. 2.5 seconds OFF
21
8-time blink
2.5 seconds OFF
22
9-time blink
2.5 seconds OFF
23
NOTE: 1. The location of LED is illustrated at the right figure. Refer to 12-6.1.
2. LED is lit 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
2.5-second OFF
OFF
OBH789H
Abnormal point/
Condition
Deceleration of the MUZ-AP25/35/42/50/60 When the input current exceeds approximate-
operational frequen-
cy of the compres-
MUZ-AP71
sor by the current
protection control
Deceleration of the Temperature of indoor coil thermistor exceeds 55°C in HEAT
operational fre- mode, compressor frequency lowers.
quency of the com-
pressor by the high
pressure protection
Deceleration of Indoor coil thermistor reads 8°C or less in COOL mode, com-
the operational pressor frequency lowers.
frequency of the
compressor by the
overcooling preven-
tion of the indoor
heat exchanger
Deceleration of the Temperature of discharge temperature thermistor exceeds
operational frequen- 111°C, compressor frequency lowers.
cy of the compres-
sor by the discharge
temperature protec-
tion
Outside temperature When the outside temperature thermistor shorts or opens,
thermistor protec- protective operation without that thermistor is performed.
tion
Low discharge tem- Temperature
perature protection of discharge
temperature
thermistor has
been
50°C or less
for 20 min-
utes.
MUZ- The overcur-
AP25/35/42/50/60 rent flows into
PFC (Power
PAM protection
factor correc-
PAM: Pulse Ampli-
tion: IC820)
tude Modulation
or the bus-
bar voltage
reaches 394 V
or more, PAM
stops and re-
starts.
MUZ-AP71 Zero cross sig-
Zero cross detecting nal cannot be
detected.
circuit
Inverter check mode The connector
of compressor
is disconnect-
ed, inverter
check mode
starts.
0.5-second ON
2.5-second OFF
Condition
ly 10A, compressor frequency lowers.
Current from power outlet is nearing breaker
capacity.
• Refer to 12-5. "Check of LEV".
• Check refrigerant circuit and refrigerant
amount.
This is not malfunction. PAM protection will
be activated in the following cases:
1 Instantaneous power voltage drop. (Short
time power failure)
2 When the power supply voltage is high.
• It occurs with following cases.
1 Instantaneous power voltage drop. (Short
time power failure)
2 Distortion of primary voltage
• Refer to 12-5. "Check of power supply".
• Check if the connector of the compressor is
correctly connected. Refer to 12-5.
check inverter/compressor".
0.5-second ON
60
Remedy
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.
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 12-5. "Check of LEV".
• Refer to 12-5. "Check of outdoor
thermistors".
• Refer to 12-5. Check of outdoor
thermistors.
• Refer to 12-5. "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.
• It occurs with following cases.
1 Instantaneous power voltage
drop. (Short time power failure)
2 Distortion of primary voltage
• Refer to 12-5. "Check of power
supply".
• Check if the connector of the com-
"How to
pressor is correctly connected.
Refer to 12-5. "How to check
inverter/compressor".
Inverter P.C. board
MUZ-AP25/35/42/50/60VG
MUZ-AP25/35/42/50VGH
Blinking →
LED
MUZ-AP71VG
Blinking
LED
MUZ-AP71VG2
LED
Blinking →