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506601−01
DEMAND
MISMATCHED
RPM
DEFAULT
FAN MOTOR
SPEED USED
LED CONTINUOUS FAST
FLASH
REPLACE FAN MOTOR
CONTROL BOARD
CRC
FAILURE
DEFAULT FAN
MOTOR
SPEED USED
LED CONSTANT ON
ONE STAGE
(LOW)
ECM1/Y1
ONLY
LED STAGE INDICATOR:
ONE SLOW FLASH AND
ONE SHORT PAUSE
LED RPM INDICATOR:
EXAMPLE: (2
−
TON) – 5
SLOW FLASHES AND
LONG PAUSE
TWO STAGE
(HIGH)
LED STAGE INDICATOR:
TWO SLOW FLASHES
AND ONE SHORT PAUSE
LED RPM INDICATOR:
EXAMPLE: (2
−
TON) – 5
SLOW FLASHES AND
LONG PAUSE
EDA
OPERATION
ECM2/Y2
ONLY
LED STAGE INDICATOR:
THREE SLOW FLASHES
AND ONE SHORT PAUSE
LED RPM INDICATOR:
EXAMPLE: (2
−
TON – 3
SLOW FLASHES AND
LONG PAUSE
DEMAND
ENDED
NO
DEMAND
ENDED
NO
DEMAND
ENDED
NO
YES
YES
FAN MOTOR
RPM SET PER
JUMPER
SETTINGS
ECM1/Y1
ONLY AND
EMC2/Y2
FAN MOTOR
RPM SET PER
JUMPER
SETTINGS
FAN MOTOR
RPM SET PER
JUMPER
SETTINGS
REPLACE FAN MOTOR
CONTROL BOARD
BEGINS
YES
Figure 34. Fan Motor Control (A177) One/Two Stage and EDA LED Sequence of Operation