Mitsubishi Electric CITY MULTI PUHY-400YMF-B, Service Handbook

Page: 171 / 204

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Discharge
(TH11)
(TH12)
Low
Pressure
Satura-
tion (TH2)
Liquid
Level
Detection
(TH3)
Liquid
Level
Detection
(TH4)
Liquid pipe
(TH5)
Ambient
Tempera-
ture
(TH6)
Liquid
Tempera-
ture
(TH7)
Outlet SC
Coil
(TH8)
Inlet SC
Coil
(TH9a)
CS circuit
(TH9b)
Heat
Exchanger
Gas
(TH10a)
Heat
Exchanger
Gas
(TH10b:
Variable
capacity unit)
Distribu-
tion pipe
tempera-
ture
(TH10b:
Constant
capacity unit)
Compressur
shell
temperature
(TH10c)
Checking code Meaning, detecting method Cause Checking method & Countermeasure
4260
5101
5102
5103
5104
5105
5106
5107
5108
5109
5112
5113
5114
5110
If the heat sink temperature (THHS)
60
°
C for 18 minutes or longer just
before the inverter starts.
1 Detects thermistor short (high
temperature pick up) during
operation or open circuit (low
temperature pick up). The out-
door unit is temporarily
stopped and it enters the 3-
minute restart prohibit mode.
If the temperature detected by
the thermistor immediately
before the restarting is within
the normal range, the unit is
restarted.
2 If a short in the thermistor or
an open circuit is detected im-
mediately before restarting, an
error stop is performed and
one of the following numbers
is displayed: 5101, 5102,
5103, 5104, 5106, 5107, 5108
or 5109.
3 During the 3-minute restart
prohibit mode, the LED for the
error stop delay will be dis-
played.
4
Short and open circuit detec-
tion is not performed for 10
minutes after the compressor
has started operation, during
defrosting and for 3 minutes
after recovery from defrosting.
5
Open circuit detection for ther-
mistor TH11, 12 is not per-
formed immediately before
starting.
If a heat sink temperature of
(THHS) – 40
°
C is detected just
before starting of and during op-
eration of the inverter.
Same as “4230.”
Check thermistor resistance.
Check for tangled lead wires.
Checking for broken covering.
Check the connector for missing pins.
Check for broken wires.
Check pick up temperature using the
LED monitor. If there is a big difference
between that temperature and the ac-
tual temperature, replace the main cir-
cuit board.
Confirm that the thermistor is
mounted in the correct place.
1) Same as “4230.”
1) Defective thermistor.
2) Tangled lead wires.
3) Broken covering.
4) Pin has come out of connector
creating connection deerror.
5) Broken wire.
6) Defective thermistor input on main
circuit board.
7) Thermistor mounting problem.
T
emper
ature sensor abnor
mality (Outdoor unit)
Short Detection Open Detection
TH11, 12 240
°
C or more ( 0.57 k
Ω
) 15
°
C or less ( 321 k
Ω
)
TH2 70
°
C or more ( 1.14 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
TH3 70
°
C or more ( 1.14 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
TH4 70
°
C or more ( 1.14 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
TH5 110
°
C or more ( 0.4 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
TH6 110
°
C or more ( 0.4 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
TH7 110
°
C or more ( 1.14 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
TH8 110
°
C or more ( 0.4 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
TH9a, b 70
°
C or more ( 1.14 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
THHS — – 40
°
C or less ( 2.5 M
Ω
)
TH10a 140
°
C or more ( 0.19 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
(Variable Capacity Unit)
(Constant Capacity Unit)
TH10b
140
°
C or more ( 0.19 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
(Variable Capacity Unit)
TH10b
110
°
C or more ( 0.4 k
Ω
) – 40
°
C or less ( 130 k
Ω
)
(Constant Capacity Unit)
TH10c
240
°
C or more ( 0.57 k
Ω
) – 15
°
C or less ( 1.6 M
Ω
)
(Variable Capacity Unit)
* The temperatures shown above and the detection ranges during operation.
When the unit is stopped, the ambient temperature will have an affect.
Therefore, compare the actual temperature and the monitor temperature
while making the determination.
Cooling fan
abnormality
(Variable
capacity unit)
Judge that the THHS has failed.
Check the contacts of CNTH on the
INV board.
If none of the items in 1) to 2) is appli-
cable, and if the trouble reappears
even after the power is switched on
again, replace the INV board (when
replacing the circuit board, be sure to
connect all the connectors, ground
wires, etc. securely).
1) The THHS sensor is defective.
2) Contact is faulty.
3) The INV board si defective.
Radiator panel
(Variable
capacity unit)