Led Monitor Display And Countermeasures Depending On The Check Code Displayed - Mitsubishi Electric CITY MULTI PUHY-400YMF-B Service Handbook

[2] LED monitor display and Countermeasures Depending on the Check Code Displayed

(1) Mechanical
Checking code Meaning, detecting method
0403 Serial If serial transmission cannot be
transmission established between the MAIN
and INV boards.
abnormality
(Variable
capacity unit)
1102 Discharge 1 When an operating outlet tem-
temperature perature of 140°C or more is
abnormality detected (first detection), the
(Outdoor unit) outdoor unit will pause and the
restart prevention mode will be
activated for 3 minutes after
which the unit will be restarted.
2 If the outdoor unit is restarted
within 30 minutes of stopping
temperature of 140°C or more
is detected again (second de-
tection), the outdoor unit will
pause again and the restart
prevention mode will be acti-
vated for 3 minutes after which
the unit will be restarted.
3 If 140°C or more is detected
again within 30 minutes of the
outdoor unit being stopped
(third detection), an error stop
is performed and "1102" is dis-
played.
4 If 140°C or 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 re-
peated.
5 The unit is in an error stop de-
lay period for 30 minutes after
the outdoor unit has been
stopped, during which the er-
ror stop delay LED is displayed.
Cause
1) Wiring is defective.
2) Switches are set wrong on the INV
board.
3) A fuse (F01) on the INV board is de-
fective.
4) The circuit board is defective.
1) Gas leakage, insufficient gas.
2) Overload operation.
3) Improper operation of indoor unit
LEV.
4) Improper operation of outdoor
LEV1.
5) Defective ball valve operation.
6) Locking of outdoor unit fan, defective
motor, all heating due to improper
operation of fan micro-computer.
3) to 6) Rise in outlet temperature
due to drawing in of low pressure.)
7) Gas leakage between high and low
pressure. (4-way valve defective,
compressor defective, solenoid
valves 1, 4 defective.)
8) Defective operation of solenoid valve
SV4.
The SV4 bypass valve cannot con-
trol rise in temperature of outlet
temperature.
9) Defective thermistor. (TH11, 12)
10)Defective thermistor input circuit on
main circuit board.
–158–
Checking method & Countermeasure
Check 1, the connections, 2, contact
at the connectors and 3, for broken
wires in the following wiring.
CNRS2 - CNRS3
CNAC2 - TB1A
SW1-4 on the INV board should be
OFF.
If the fuse is melted, (if the resistance
between the both ends of fuse is ∞),
replace the fuse.
If none of the items in 1) to 3) is appli-
cable, and if the trouble reappears
even after the power is switched on
again, replace the circuit board by the
following procedure (when replacing
the circuit board, be sure to connect
all the connectors, ground wires, etc.
securely).
1 If serial transmission is restored
after the INV board only is re-
placed, then the INV board is de-
fective.
2 If serial transmission is not re-
stored, reinstall the INV board and
replace the MAIN board. If serial
transmission is restored, the MAIN
board is defective.
3 If serial transmission is not restored
by 1 and 2 above, replace both
boards.
Refer to Refrigerant amount check.
Check the operating condition of the
indoor unit and operating status.
Perform actual cooling or heating and
check operating condition (Check op-
eration of LEV).
Cooling: Indoor LEV LEV1
Heating: Indoor LEV
See Trouble cehck of LEV and sole-
noid valve.
Check if ball valve is completely open.
* Inspect outdoor unit fan.
* Refer to Trouble check of outdoor
fan.
Confirm operating statue by perform-
ing both heating and cooling opera-
tions.
Refer to Trouble check of colenoid
valve.
Check resistance of thermistor.
Use LED monitor to check the tem-
perature taken by the sensor and
whether or not there are any problems
with connector connections.