Hitachi FSXN Series Service Manual page 162

8 Troubleshooting
(only for RAS-(14-18)FSXN)
This function is an emergency mode operation that uses the other compressor when the constant speed compressor fails.
Alarms corresponding to a failure of the constant speed compressor
Code
23
39
(a) Procedure:
1. Turn OFF the main switches to all indoor and outdoor units.
2. Turn ON DSW5 on PCB1 of the outdoor unit for the failure of the constant speed compressor.
3. Turn ON the power supply.
4. Start the operation using the remote control switch.
(b) Operating condition:
• Td thermistor
Td thermistor is ignored during a failure of the constant speed compressor due to the setting of DSW5. If the thermistor
is short-circuited, this operation is available.
N O T E
• Measure the insulation resistance of the constant speed compressor.
Do not activate the emergency operation when the insulation resistance is 0 Ω.
Another compressor may be damaged due to the possibility that refrigerant oil may be oxidized.
• In emergency operation, the compressor frequency cannot normally be controlled.
Consequently, alarm codes "07", "43", "44", "45" or "47" can be displayed on the LCD.
• The emergency operation cannot provide sufficient cooling and heating capacity.
• The emergency operation is a temporary mode of operation used when the constant speed compressor is
damaged. Therefore, replace it with a new one as soon as possible.
• Turn OFF DSW5 on PCB1 after replacing the compressor.
If this setting is not carried out, the constant speed compressor will be damaged.
156
SMGB0065 rev. 1 - 12/2010
Abnormal discharge gas thermistor
Abnormal running current in constant speed compressor
(DSW5)
ON
1 2 3 4 5 6
Description of the failure
PCB1