Vermont Casting MSZ-D36NA User Manual

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2. Indoor unit failure mode table
NOTE
 : Blinking patterns of this mode differ from the ones of Troubleshooting check table (9-4.). 
Left lamp of OP-
ERATION INDICA-
TOR lamp 
Abnormal point 
(Failure mode) 
Condition Correspondence 
Not lighted 
Normal 
1-time fl ash every 
0.5-second 
Room temperature 
thermistor 
The room temperature thermistor short or open 
circuit is detected every 8 seconds during op-
eration. 
Refer to the characteristics of the room temperature 
thermistor (9-7.). 
2-time fl ash 
2.5-second OFF 
Indoor coil thermis-
tor 
The indoor coil thermistor short or open circuit 
is detected every 8 seconds during operation. 
Refer to the characteristics of the main indoor coil 
thermistor, the sub indoor coil thermistor (9-7.). 
3-time fl ash 
2.5-second OFF 
Serial signal 
The serial signal from outdoor unit is not re-
ceived for a maximum of 6 minutes. 
Refer to 9-6.  "How to check miswiring and serial 
signal error". 
11-time fl ash 
2.5-second OFF 
Indoor fan motor 
The rotational frequency feedback signal is 
not emit during the 12 seconds the indoor fan 
operation. 
Refer to 9-6.  "Check of indoor fan motor". 
12-time fl ash 
2.5-second OFF 
Indoor control 
system 
It cannot properly read data in the nonvolatile 
memory of the indoor electronic control P.C. 
board. 
Replace the indoor electronic control P.C. board.