Mitsubishi Electric CITY MULTI PUHY-400YMF-C Service Handbook page 165

Checking code Meaning, detecting method
5101 Discharge
1 Detects thermistor short (high
(TH11)
temperature pick up) during
(TH12)
operation or open circuit (low
temperature pick up). The out-
5102 Low
d o o r u n i t i s t e m p o ra r i l y
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
5104 Liquid
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
5106 Ambient
prohibit mode, the LED for the
Tempera-
error stop delay will be dis-
ture
(TH6) played.
4 Short and open circuit detec-
Liquid
5107
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)
Cause
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.
Short Detection
TH11, 12 240 C or more ( 0.57 k )
TH2 70 C or more ( 1.14 k )
TH3 70 C or more ( 1.14 k )
TH4 70 C or more ( 1.14 k )
TH5 110 C or more ( 0.4 k )
TH6 110 C or more ( 0.4 k )
TH7 110 C or more ( 1.14 k )
TH8 110 C or more ( 0.4 k )
TH9a, b 70 C or more ( 1.14 k )
THHS —
TH10a 140 C or more ( 0.19 k )
(Variable Capacity Unit)
(Constant Capacity Unit)
TH10b 140 C or more ( 0.19 k )
(Variable Capacity Unit)
TH10b 110 C or more ( 0.4 k )
(Constant Capacity Unit)
TH10c 240 C or more ( 0.57 k )
(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.
-162-
Checking method & Countermeasure
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 k )
– 40 C or less ( 130 k )
– 40 C or less ( 130 k )
– 40 C or less ( 130 k )
– 40 C or less ( 130 k )
– 40 C or less ( 130 k )
– 40 C or less ( 130 k )
– 40 C or less ( 130 k )
– 40 C or less ( 130 k )
– 40 C or less ( 2.5 M )
– 40 C or less ( 130 k )
– 40 C or less ( 130 k )
– 40 C or less ( 130 k )
– 15 C or less ( 1.6 M )