Mitsubishi Electric CITY MULTI PUHY-400YMF-B Service Handbook page 171

Checking code Meaning, detecting method
Cooling fan
4260 If the heat sink temperature (THHS)
abnormality
60°C for 18 minutes or longer just
(Variable
before the inverter starts.
capacity unit)
5101 Discharge 1 Detects thermistor short (high
(TH11)
temperature pick up) during
(TH12)
operation or open circuit (low
temperature pick up). The out-
Low
5102
door unit is temporarily
Pressure
stopped and it enters the 3-
Satura-
minute restart prohibit mode.
tion (TH2)
If the temperature detected by
the thermistor immediately
Liquid
5103
before the restarting is within
Level
the normal range, the unit is
Detection
(TH3) restarted.
2 If a short in the thermistor or
Liquid
5104
an open circuit is detected im-
Level
mediately before restarting, an
Detection
error stop is performed and
(TH4)
one of the following numbers
is displayed: 5101, 5102,
Liquid pipe
5105
5103, 5104, 5106, 5107, 5108
(TH5)
or 5109.
3 During the 3-minute restart
Ambient
5106
prohibit mode, the LED for the
Tempera-
error stop delay will be dis-
ture
(TH6) played.
4 Short and open circuit detec-
5107 Liquid
tion is not performed for 10
Tempera-
minutes after the compressor
ture
has started operation, during
(TH7)
defrosting and for 3 minutes
after recovery from defrosting.
5108 Outlet SC
5 Open circuit detection for ther-
Coil
mistor TH11, 12 is not per-
(TH8)
formed immediately before
starting.
5109 Inlet SC
Coil
(TH9a)
CS circuit
(TH9b)
5112 Heat
Exchanger
Gas
(TH10a)
5113 Heat
Exchanger
Gas
(TH10b:
Variable
capacity unit)
Distribu-
tion pipe
tempera-
ture
(TH10b:
Constant
capacity unit)
5114 Compressur
shell
temperature
(TH10c)
If a heat sink temperature of
Radiator panel
5110
(THHS)
(Variable
capacity unit) before starting of and during op-
eration of the inverter.
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.
TH11, 12
TH2
TH3
TH4
TH5
TH6
TH7
TH8
TH9a, b
THHS
TH10a
(Variable Capacity Unit)
(Constant Capacity Unit)
TH10b
(Variable Capacity Unit)
TH10b
(Constant Capacity Unit)
TH10c
(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.
1) The THHS sensor is defective.
– 40°C is detected just
2) Contact is faulty.
3) The INV board si defective.
Cause
Short Detection
240°C or more ( 0.57 kΩ)
70°C or more ( 1.14 kΩ)
70°C or more ( 1.14 kΩ)
70°C or more ( 1.14 kΩ)
110°C or more ( 0.4 kΩ)
110°C or more ( 0.4 kΩ)
110°C or more ( 1.14 kΩ)
110°C or more ( 0.4 kΩ)
70°C or more ( 1.14 kΩ)
—
140°C or more ( 0.19 kΩ)
140°C or more ( 0.19 kΩ)
110°C or more ( 0.4 kΩ)
240°C or more ( 0.57 kΩ)
–168–
Checking method & Countermeasure
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.
Open Detection
15°C or less ( 321 kΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 2.5 MΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 130 kΩ)
– 40°C or less ( 130 kΩ)
– 15°C or less ( 1.6 MΩ)
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).