Mitsubishi Electric CITY MULTI, Техническое и сервисное руководство

Страница: 82 / 160

Check code
Abnormal points and detection methods Causes and checkpoints
If TH3 detects to be open/short.
(The open/short detection is disabled during 10 seconds to 10 minutes
after compressor starts, during defrosting operation, or for 10 minutes after
returning from the defrosting operation.)
Open:−40 [−40°F] or less
Short: 90 [162°F] or more TH3: Thermistor <Outdoor liquid pipe>
Disconnection or contact failure of connectors
Characteristic defect of thermistor
Defective outdoor multi controller circuit board
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting
any connectors, or replacing boards.
Diagnosis Remedy
5105
(U4)
Outdoor liquid pipe temperature thermistor (TH3) open/short
The black square (■) indicates a switch position.
SW1 Setting
ON
OFF
Display on LED1, 2 Unit
−99.9–999.9
_
C
4 1 2 5 6 7 8 3
No
Yes
Yes
Yes
No
No
Is there any abnormality such
as disconnection, looseness or
breakage?
Is the detected resistance normal?
Is the detected temperature normal?
Connect the wiring/connector properly
Replace it in the case of breakage.
Replace the thermistor.
Replace the outdoor multi controller circuit
board (Malfunction of thermistor circuit).
No abnormality
(A connector contact failure is suspected.)
Check the wiring and connector connection of TH3.
Disconnect the connector to check the
resistance of TH3 using a multimeter.
Check the temperature of TH3.
The detected temperature of TH3 can be displayed by an
operation of SW1 on the outdoor multi controller circuit board
82 83
OCH673D