Mitsubishi Electric FDT125VNVF Technical Manual page 387

Error code
E21
Remote controller:
1. Applicable model
FDT series only
2. Error detection method
Panel switch (PS) has detected
Open for more than 1 second.
3. Condition of Error displayed
Same as above
4. Presumable cause
• Defective panel switch
• Disconnection of wiring
• Defective indoor control PCB
Note:
LED Green Red
Keeps flashing 1 time flash
Indoor
Keeps flashing Stays OFF
Outdoor
5. Troubleshooting
Diagnosis
Is grill opened?
NO
Does
matter improve if panel
switch is turned ON forcibly
after resetting
error?
NO
Are connectors at right
inserted properly?
YES
Is there
continuity between
#1 – #4 of CNV on indoor control PCB
when panel switch operation
is checked?
386
-
Defective panel switch
Content
operation (FDT)
YES
YES
<Forced panel switch ON>
Put the switch in the state of
ON by fixing the silicone
section of panel switch with
adhesive tape while it is held
down.
NO
<Connectors on PCBs>
Indoor control PCB: CNV
NO
YES
-
'12 • PAC-T-174
Countermeasure
Reset the error and close
the grill.
Insufficient push on the
panel switch at the internal
face of grill
➞ Attach 3 mm thick
rubber sheet at the section
where the panel switch
touches the inside of grill.
Close then the grill.
Disconnected, poorly
connected connectors
➞ Reinsert properly.
→To CNY1
Panel switch
Silicone guide Push to turn ON.
・ Defective panel switch
or incorrect panel switch
wiring ➞ Replace panel
switch.
・ Broken wire between panel
switch PCB (CNV) ➞ Correct
or replace wire.
Defective indoor control
PCB ➞ Replace indoor
control PCB.