Mitsubishi Electric MSH09TW Service Manual page 79

MXZ30TN MXZ30TN2
Note . LED indicates "00" in the normal status.
7-segment LED display
00
If there is defect in the following parts(electronic control P.C. board, relay P.C. board, high pressure
switches(63H1,63H2),indoor /outdoor fan motor , or indoor coil thermistor), the compressor may stop even with the display
remained at " 00 ".In any case, reset the breaker and check the above-stated parts.
Symptom
Display Abnormal
a a 4 4
Outdoor power system abnor-
mality
(A4)
a a 3 3
Outdoor electronic control P.C.
board abnormality
(A3)
Symptom
Display Abnormal
e e 9 9
Evaporation temperature ther-
mistor abnormality
(E9)
e e 6 6
Discharge temperature ther-
mistor abnormality
(E6)
f f 8 8
Fin temperature thermistor
abnormality
(F8)
a a 8 8
Overcurrent protection
(A8)
d d 6 6
Discharge temperature over-
heat protection
(d6)
d d 4 4
Fin temperature overheat pro-
tection
(d4)
d d 7 7
High pressure protection
(d7)
f f 5 5
Room-A gas pipe temperature
thermistor abnormality
(F5)
f f 6 6
Room-B gas pipe temperature
thermistor abnormality
(F6)
f f 7 7
Room-C gas pipe temperature
thermistor abnormality
(F7)
Error mode
Normal
Outdoor unit does not operate.
Detecting method
When the compressor operation has been interrupted by overcurrent
protection continuously three times within 1 minute after start-up, the
compressor stops operation.
When the nonvolatile memory data cannot be read properly on the out-
door controller board
Outdoor unit stops and restarts every 3 minutes.
Detecting method
The compressor stops when a short or open circuit occurs in the evap-
oration temperature thermistor during compressor running.
The compressor stops when a short or open circuit occurs in the dis-
charge temperature thermistor during compressor running.
The compressor stops when a short or open circuit occurs in the fin tem-
perature thermistor during compressor running.
When over current is applied to the power module, the compressor
stops and restarts in 3 minutes.
When the discharge temperature thermistor detects 240.8°F or above,
the compressor stops and restarts operation in 3 minutes.
(Protection will be released at 212°F or below.)
When the fin temperature thermistor detects 192.2°F or above, the com-
pressor stops and restarts operation in 3 minutes.
When the compressor starts, primary current or output voltage stops the
compressor and restarts in 3 minutes.
When a short or open circuit occurs in the Room-A gas pipe
temperature thermistor.
When a short or open circuit occurs in the Room-B gas pipe
temperature thermistor.
When a short or open circuit occurs in the Room-C gas pipe
temperature thermistor.
79
Check points
• Inverter output
• Compressor
• Outdoor electronic control P.C. board
Check points
• Check the characteristic of the evapora-
tion temperature thermistor. Refer to
on page 90.
• Check the contact of P. C. board con-
nectors.
• Check the characteristic of the discharge
temperature thermistor. Refer to K K on
page 90.
• Check the contact of P. C. board con-
nectors.
• Check the characteristic of the fin temper-
ature thermistor. Refer to K K on page 90.
• Check the contact of P.C. board connec-
tors.
• Check the inverter and compressor.
Refer to J J on page 89.
• Check the amount of gas.
• Check the indoor/outdoor air flow for
short cycle.
• Check the indoor unit air filter for
clogging.
• Check the amount of gas and the refriger-
ant cycle.
• Check the outdoor unit air passage.
• Check the outdoor unit air passage.
• Check the power module.
• Check the outdoor fan motor. Refer to L L
on page 91.
• Amount of gas
• Outdoor unit air passage.
• Check the ball valve.
• Room A gas pipe temperature thermistor
characteristic.
• Contact of P.C. board connectors.
• Room B gas pipe temperature thermistor
characteristic.
• Contact of P.C. board connectors.
• Room C gas pipe temperature thermistor
characteristic.
• Contact of P.C. board connectors.
K K