Mitsubishi Heavy Industries FDU Series Service Manual page 86

Error code
E9
Remote control:
1. Applicable model
FDT, FDU, FDUM series only
2. Error detection method
Float switch is activated
3. Condition of Error displayed
If the float switch OPEN
is detected for 3 seconds
continuously or if float
switch connector or wire is
disconnected.
4. Presumable cause
• Defective indoor unit control
or power PCB
• Float switch setting error
• Humidifier drain pump motor
interlock setting error
• Optional equipment setting
error
• Drain piping error
• Defective drain pump motor
• Disconnection of drain pump
motor wiring
Note:
When this error occurred at power ON, disconnection of wire or connector of the float switch is suspected. Check and
correct it (or replace it, if necessary).
LED Green Red
Keeps flashing 1-time flash
Indoor
5. Troubleshooting
Diagnosis
Check the error data in the remote control.
Is there any overflow?
YES
Is the humidifier connected?
YES
Is the
humidifier drain pump motor
interlocked by the indoor unit function
setting of remote
control?
YES
Drain pump motor ON from the remote control
Does drain pump motor
operate?
YES
Is the drain
piping unclogged? Is the
drain pipe slop
OK?
85
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Content
Drain trouble
(FDT, FDU, FDUM series)
NO
Is DC 12V
at CNI connector.
NO
YES
Is the
CNI connected
NO
firmly?
YES
Is
there any
NO
anomaly on the optional
equipment?
YES
NO
NO
Is
DC12V
NO
detected at CNR
connector?
YES
NO
YES
-
'19 • PAC-SM-334
Countermeasure
Check float switch.
Defective indoor unit
control PCB ➞ Replace.
Defective indoor unit
control PCB ➞ Replace.
Check option equipment.
Correct setting to
"Humidifier drain pump
motor interlock".
Defective indoor unit
NO
control PCB ➞ Replace.
Check wiring of drain
pump motor.
Correct.
Check drain pump motor.