MITSUBISHI ELECTRIC MXZ-24UV - Manual (Page 25)

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Outdoor power system abnor-
mality
When the compressor operation has been interrupted by overcurrent
protection continuously three times within 1 minute after start-up, the
compressor stops operation.
• Inverter output
• Compressor
Display Detecting method Detecting method Check points
Symptom Outdoor unit does not operate.
Note . LED indicates " 00 " in the normal status.
7-segment LED display Error mode
Normal
Outdoor electronic control P.C.
board abnormality When the nonvolatile memory data cannot be read properly on the out-
door controller board
• Outdoor electronic control P.C. board
Indoor unit and LEV abnor-
mality
When the drain abnormality is detected in the indoor unit and the indoor
main coil temperature is too low, or when any abnormality is detected in
the components of indoor unit • Check the abnormality indication on the
indoor unit.
• LEV
Display Detecting method Detecting method Check points
Symptom Outdoor unit stops and restarts every 3 minutes.
Evaporation temperature ther-
mistor abnormality The compressor stops when a short or open circuit occurs in the evap-
oration temperature thermistor during compressor running.
• Check the characteristic of the evapora-
tion temperature thermistor. Refer to F F
on page 31.
• Check the contact of P. C. board con-
nectors.
Discharge temperature ther-
mistor abnormality The compressor stops when a short or open circuit occurs in the dis-
charge temperature thermistor during compressor running.
• Check the characteristic of the discharge
temperature thermistor. Refer to F F on
page 31.
• Check the contact of P. C. board con-
nectors.
Fin temperature thermistor
abnormality The compressor stops when a short or open circuit occurs in the fin tem-
perature thermistor during compressor running.
• Check the characteristic of the fin temper-
ature thermistor. Refer to F F on page 31.
• Check the contact of P.C. board connec-
tors.
Overcurrent protection
When over current is applied to the power module, the compressor
stops and restarts in 3 minutes.
• Check the inverter and compressor.
Refer to E E on page 30.
• Check the amount of gas.
• Check the indoor/outdoor air flow for
short cycle.
• Check the indoor unit air filter for
clogging.
Discharge temperature over-
heat protection
When the discharge temperature thermistor detects 116˚C or above, the
compressor stops and restarts operation in 3 minutes.
(Protection will be released at 100
; or below.)
• Check the amount of gas and the refriger-
ant cycle.
• Check the outdoor unit air passage.
Fin temperature overheat pro-
tection When the fin temperature thermistor detects 89˚C or above, the com-
pressor stops and restarts operation in 3 minutes.
• Check the outdoor unit air passage.
• Check the power module.
• Check the outdoor fan motor. Refer to
G G
on page 31.
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.
a a44
(A4)
a a3 3
(A3)
p p11
(P1)
e e9 9
(E9)
e e6 6
(E6)
f f8 8
(F8)
a a8 8
(A8)
d d6 6
(d6)
d d44
(d4)
High pressure protection
When the compressor starts, primary current or output voltage stops the
compressor and restarts in 3 minutes.
• Amount of gas
• Outdoor unit air passage.
• Check the ball valve. d d77
(d7)
12-3. Troubleshooting check table
Room-A gas pipe temperature
thermistor abnormality When a short or open circuit occurs in the Room-A gas pipe
temperature thermistor.
• Room A gas pipe temperature thermistor
characteristic.
• Contact of P.C. board connectors.
Room-B gas pipe temperature
thermistor abnormality When a short or open circuit occurs in the Room-B gas pipe
temperature thermistor.
• Room B gas pipe temperature thermistor
characteristic.
• Contact of P.C. board connectors.
Room-C gas pipe temperature
thermistor abnormality When a short or open circuit occurs in the Room-C gas pipe
temperature thermistor.
• Room C gas pipe temperature thermistor
characteristic.
• Contact of P.C. board connectors.
f f55
(F5)
f f77
(F7)
f f6 6
(F6)
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