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

Page: 164 / 204

–161–
A error is detected in the outlet
temperature super heat (TH11,
12-Tc) and in the liquid level in the
accumulator as indicated below.
1 If the liquid level in the accumu-
lator AL = 2 (over level) devel-
ops during operation, (1st de-
tection), the outdoor unit is tem-
porarily stopped and it enters
the re-start prohibit mode for 3
minutes after which it is started.
2 If liquid level in the accumulator
AL = 2 (over level) is detected
again within 30 minutes of the
stopping of the outdoor unit,
(2nd detection), the outdoor unit
is an error stop is performed and
“ 1500 “ is displayed.
3 If liquid level in the accumula-
tor AL = 2 (over level) more is
detected after 30 minutes has
passed since the outdoor unit
was stopped, it is treated as
the first detection and
1
above
is repeated.
1. When the unit condition is as
follows, the compressor is
stopped (1st detection) and
after 3 minutes, the compres-
sor is restarted automatically.
• R22 refrigerant models:
1) Cooling mode
1
F < 60 Hz, TH1 > 120
°
C,
TH1-Tc > 60deg
2) Heating mode
1
F < 60 Hz, TH1 > 100
°
C,
TH1-Tc > 55deg. TH5 > 15
°
C
2 F < 60 Hz, TH1 > 120
°
C,
TH1-Tc > 70deg.
TH5 15
°
C.
• R407C refrigerant models:
F
1
< 60 Hz, TH10c > 85
°
C
F
1
60 Hz, TH10c > 100
°
C
2. If the temperature rises again
as above within 2 hours after
the outdoor unit is stopped
(2nd detection), an error stop
is performed, and the check
code 1501 is displayed.
3. If the temperature rises again
as above within 2 hours after
the outdoor unit is stopped, it
becomes the first detection
again, and operation is the
same as in 1 above.
4. The 2 hour period after the
outdoor unit stops is the ab-
normal delay period, and LED
display is carried out during
the abnormal stop delay.
Checking code Meaning, detecting method Cause Checking method & Countermeasure
1500
1501
Overcharged
refrigerant
abnomality
(Outdoor unit) Refer to Refrigerant amount check .
Check resistance of thermistor.
Check temperature and pressure of
sensor with LED monitor.
Check thermistor mounting
Refer to solenoid valve troubleshoot-
ing
Refer to LEV troubleshooting
5
If the error pick-up prohibit switch
(SW2-4) is set to ON, all
detection after the 2nd detection
is treated as the first detection
and
1
above is repeated.
Refer to the item on judging the refrig-
erant volume.
Check the indoor and outdoor unit
operating conditions.
Actually run the equipment in cooling
or heating mode and check the oper-
ating condition.
Cooling: Indoor LEV
LEV1
SLEV
Cooling: Indoor LEV
SLEV
Refer to the item concerning judging
LEV failure.
Check with the ball valve fully open.
Check the thermistor’s resistance.
Check the sensor’s temperature read-
ing by the LED monitor.
1) Excessive refrigerant charge.
2) Broken wire of liquid level heater.
3) Poor heater output caused by con-
trol circuit board trouble.
4) Thermistor trouble (TH2, TH3, TH4).
5) Thermistor input circuit trouble on
control circuit board.
6) Poor mounting of thermistor.
(TH11, TH12, TH2, TH3, TH4,
TH10a, TH10b)
7) Constant capacity unit SV5b error
8) Constant capacity unit LEV2 error
4
The unit is in an error stop delay
period for 30 minutes after the
outdoor unit has been stopped,
during which time the error stop
delay LED is displayed.
1) Gas leakage, insufficient gas.
2) Overload operation.
3) Indoor unit LEV operation is faulty.
4) Outdoor unit LEV operation is faulty.
5) Outdoor unit SLEV operation is faulty.
6) Ball valve operation is faulty.
7) The thermistor is faulty.
8) The control board’s thermistor input
circuit is faulty.
Insufficient refr
iger
ant abnor
mality
Lacked
refrigerant
abnor-
mality
(Variable
capacity
unit)