Service manual

11-6
TROUBLESHOOTING
SM SX DCI 1-A.3 GB
No. Fault Probable Cause Corrective Action
8 Compressor Lock
Switch unit to STBY and
restart
If still not ok check compressor
(11.5.4)
If comp is ok replace OU
controller
If compressor is not ok replace
compressor
9 Bad Communication
Communication quality
is low reliability
Check Indoor to Outdoor
wiring and grounding
11.4 Judgment by MegaTool
MegaTool is a special tool to monitor the system states.
Using MegaTool requires:
• A computer with RS232C port.
• A connection wire for MegaTool.
• A special MegaTool software.
Use MegaTool according to following procedure:
• Setup MegaTool software: copy the software to the computer.
• Connect RS232C port in computer with MegaTool port in Indoor/Outdoor unit controller by
the connection wire.
• Run the software and choose the COM port, you can monitor the A/C system state in
monitor tab.
11.5 Simple procedures for checking the Main Parts
11.5.1 Checking Mains Voltage.
Confirm that the Mains voltage is between 198 and 264 VAC. If Mains voltage is out of this
range, abnormal operation of the system is expected. If in range check the Power (Circuit)
Breaker and look for broken or loosed cable lugs or wiring mistake(s).
11.5.2 Checking Power Input.
If Indoor unit power LED is unlighted, power down the system and check the fuse of the Indoor
unit. If the fuse is OK replace the Indoor unit controller. If the fuse has blown, replace the fuse
and power up again.
Checking Power Input procedure for the Outdoor unit is the same as with the Indoor unit.
11.5.3 Checking the Outdoor Fan Motor.
Enter Test Mode (where the OFAN speed is high)
Check the voltage between lead wires according to the normal value as following:
• Between red wire and black wire: 310VDC +/- 20V
• Between orange wire and black wire: 15VDC +/- 1V
• Between yellow wire and black wire: 2-6VDC
CONTENT