Mitsubishi Electric MXZ-2F33VF -E1 Service Manual page 160

Indication
No. Symptom
LED1(Red) LED2(Yellow)
20 5 times
21 6 times
22 8 times
'Outdoor unit
stops and
restarts
23 9 times
3 minutes
later' is
repeated.
24 11 times
25 13 times
26 Lit
27 Lit 11 times
28 Lit 12 times
29 Once
30 Twice
31 3 times
32 4 times
33 5 times
Outdoor unit
operates.
34 7 times
35 11 times
OBH790H
Abnormal point /
Condition
High pressure
Not lit
protection
Not lit Pre-heating protection
Not lit Converter protection
Bus-bar voltage
Not lit
protection
Low outside tempera-
Not lit
ture protection(cooling)
Not lit Outdoor fan motor
Current sensor protec-
8 times
tion
Communication
between P.C. boards
protection
Zero cross detecting
circuit (Outdoor power
P.C. board)
Primary current protec-
Lit
tion
High pressure protec-
tion
Lit
Defrosting in cooling
Discharge temperature
Lit
protection
Low discharge
Lit
temperature protection
Cooling high pressure
Lit
protection
High Low
Pressure bypass
valve
Cooling evaporating
temperature drop
prevention control
High Low
Lit pressure bypass valve
High pressure protec-
tion control at startup of
heating operation
High Low
pressure bypass valve
Compressor oil temper-
ing control at startup of
heating operation
M-NET communication
Lit
error
Condition
High pressure is detected with the high pressure
switch (HPS) during operation.
The outdoor heat exchanger temperature exceeds
70°C during cooling or the indoor gas pipe tem-
perature exceeds 70°C during heating.
Overcurrent is detected during pre-heating.
A failure is detected in the operation of the convert-
er during operation.
The bus-bar voltage exceeds 400 V or falls to low
level during compressor operating.
The ambient became -12°C or less.
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 13.6 A (MXZ-2F53VFHZ)/
15 A (MXZ-3F54/3F68/4F72VF/VF2/VF3/4F80VF2/
VF3)/18.4 A (MXZ-4F83/5F102VF)/26.8AMXZ-
6F122VF)/25 A (MXZ-4F83VFHZ).
The indoor gas pipe temperature exceeds 45°C
during heating.
The indoor gas pipe temperature falls 3°C or below
during cooling.
The frequency of the compressor is kept 80 Hz or
more and the discharge temperature is kept under
50°C(COOL mode)/40°C(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
39°C for more than 20 minutes.
The outdoor heat exchanger temperature exceeds
58°C during operation.
MXZ-MXZ-3F54/3F68/4F72VF/VF2/VF3/4F80VF2/
VF3
During cooling operation, the temperature of indoor
heat exchanger becomes 3°C or less within 1 hour
after the compressor starts running, or it becomes
less than 12°C - 16°C* later than that.
* It depends on the difference between the set
temperature and the room temperature.
MXZ-6F122VF, MXZ-4F83VFHZ
The room temperature is 24°C or more when 1 or
2 unit(s) start(s) the heating operation.
MXZ-6F122VF, MXZ-4F83VFHZ
Both the following are true:
• The outside temperature is -2°C or less when the
heating operation is started.
• [(Discharge temperature) - (Indoor heat exchang-
er temperature)] < 5°C
M-NET adapter P.C. board detects an abnormality
in the communication error.
160
Remedy
• Check around of gas and the refrigerant circuit.
• Check the stop valve.
• Reconnect compressor connector.
• Refer to 12-6. "How to check inverter/
compressor".
• Check the power module.
• Replace the outdoor power P.C. board.
• Check the voltage of power supply.
• Replace the outdoor power P.C. board or the out-
door control P.C. board.
• Refer to 12-6. "Check of bus-bar voltage".
—
• Refer to 12-6. "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.
• Replace the outdoor power P.C. board.
These symptoms do not mean any abnormality of
the product, but check the following points.
• 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 refrigerant amount.
• Refer to 12-6. "Check of LEV".
• Refer to 12-6. "Check of outdoor thermistors".
• Refer to 12-6. "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 filters are clogged.
• Check if refrigerant is short.
• Check if indoor/outdoor unit air circulation is short
cycled.
This symptom does not mean any abnormality of
the product, but check the following points.
• Check the indoor filters are not clogged.
• Check there is sufficient refrigerant.
• Check the indoor/outdoor unit air circulation is not
short cycled.
• Check the connecting wire between M-NET
adapter P.C. board and outdoor control P.C.
board, or terminal block.