Mitsubishi Electric MXZ-3C24NA Service Manual page 64

Indication
No. Symptom
LED1(Red) LED2(Yellow)
21 'Outdoor unit
13 times Not lighted
stops and
restarts
22
Lighted
3 minutes
later' is
23
repeated.
Lighted
24
Lighted
25 Outdoor unit
Once
operates.
26
Twice
27
3 times
28
4 times
29
5 times
30 Outdoor
9 times
unit
operates
31
Lighted
normally.
NOTE 1. The location of LED is illustrated at the right figure. Refer to 11-7.1.
2. LED is lighted during normal operation.
The flashing frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the flashing frequency is "2".
ON
2.5-second OFF
OFF
OBH702A
Abnormal point / Con-
dition
Outdoor fan motor
Current sensor protec-
8 times
tion
Communication
11 times between P.C. boards
protection
Zero cross detecting
12 times
circuit protection
Primary current protec-
Lighted
tion
High-pressure protec-
tion
Lighted
Defrosting in cooling
Discharge temperature
Lighted
protection
Low discharge
Lighted
temperature protection
Cooling high-pressure
Lighted
protection
Lighted Inverter check mode
Lighted Normal
0.5-second ON
2.5-second OFF
Condition
A failure occurs 3 consecutive times within 30
seconds after the fan gets started.
A short or open circuit is detected in the current
sensor during compressor operating.
Communication error occurs between the outdoor
control P.C. board and outdoor power P.C. board
for more than 10 seconds.
Zero cross signal cannot be detected while the
compressor is operating.
The input current exceeds 15 A.
The indoor gas pipe temperature exceeds 113 °F
during heating.
The indoor gas pipe temperature falls 37.4 °F or
below during cooling.
The frequency of the compressor is kept 80 Hz or
more and the discharge temperature is kept under
122 °F(COOL mode)/104 °F(HEAT mode) for more
than 40 minutes.
The frequency of the compressor is kept 80 Hz or
more and the discharge temperature is kept under
102.2 °F for more than 20 minutes.
The outdoor heat exchanger temperature exceeds
136.4 °F during operation.
The unit is operated with emergency operation
switch.
—
0.5-second ON
64
Remedy
• Refer to 11-6. "Check of outdoor fan motor".
• Replace the outdoor power P.C. board.
• Check the connecting wire between outdoor con-
trol P.C. board and outdoor power P.C. board.
• Check the connecting wire among outdoor control
P.C. board and outdoor power P.C. board.
These symptoms do not mean any abnormality of
the product, but check the following points.
• 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 refrigerant amount.
• Refer to 11-6. "Check of LEV".
• Refer to 11-6. "Check of outdoor thermistors".
• Refer to 11-6. "Check of LEV".
• Check refrigerant circuit and refrigerant amount.
This symptom does not mean any abnormality of
the product, but check the following points.
• Check if indoor fi lters are clogged.
• Check if refrigerant is short.
• Check if indoor/outdoor unit air circulation is short
cycled.
—
—
Outdoor control P.C. board
(Parts side)
LED1 LED2
Lighted