Toshiba HFC R407C Service Manual page 40

Diagnostic procedure for check code
Check code
[0b]
Drain pump fault
Indoor unit or Multi
Controller
Is drain pump connected?
Yes
Does float switch operate?
Yes
Does drainage water collect?
Yes
Does drain pump operate?
Yes
Check for blockage of
drainage hose.
Check code
[0C]
Indoor sensor (TA) short or open circuit alarm
TA sensor open/short has been detected. Check disconnection of connector connection (TA sensor: CN04)
circuit and resistance value characteristics of sensor.
When the sensors are normal, replace indoor PC board (MCC-1292).
Check code
[0D]
Indoor sensor (TC) short 'Preheat defrost' is
or open circuit alarm
TC sensor open/short has been detected. Check disconnection of connection (TC sensor: CN05) circuit
and resistance value characteristics of sensor.
When the sensors are normal, replace indoor PC board (MCC-1292).
40
Troubleshooting
Status of air conditioner
Operation stops for Multi
Controller fault.
Indoor unit fan continues for 3. Drain hose blockage.
unit fault.
No
No
Is circuit wiring
normal?(*1)
(*1) For confirmation, check voltage under condition that
connector is connected to CN10, pins 5 and 7,
PJ10, pins 1 and 2
No
No
Is power to drain
pump turned on?(*2)
Drain pump error
Status of air conditioner
Indoor unit fan stops.
displayed on R/C.
Operation cause
1. Float switch disconnection.
2. Drain pump operation error.
Check connection of connector CN10
(Drain pump: Multi Controller, PC board
No
No
Yes
(*2) Check whether voltage of CN10/PJ10, pins
1 and 2/1 to 3 of the indoor main PC board,
is 230V or not (MCC-1292), (MCC-1210).
Operation cause
TA sensor open/short
Operation cause
TC sensor open/short
(Drain pump: Indoor main, PC board
(MCC-1292), CN10)
(MCC-1210) PJ10)
Check and modify wiring circuit.
(MCC-1292), (MCC-1210)
Indoor PC board error
(MCC-1292), (MCC-1210)
Float switch error
Check and modify wiring
circuit.