Lennox XC21 Installation Instructions Manual page 44

DEMAND
BEGINS
MISMATCHED
RPM
CRC
FAILURE
ONE STAGE
(LOW)
NO
DEMAND
ENDED
TWO STAGE
(HIGH)
NO
DEMAND
ENDED
EDA
OPERATION
NO
DEMAND
ENDED
Figure 23. A177 Fan Motor Control One/Two Stage and EDA LED Sequence of Operation
506518−01
FAN MOTOR PWM CONTROL (TWO STAGE AND VARIABLE SPEED FAN
DEFAULT
FAN MOTOR
SPEED USED
DEFAULT FAN
MOTOR
SPEED USED
FAN MOTOR
ECM1/Y1 RPM SET PER
ONLY
YES
FAN MOTOR
ECM1/Y1
RPM SET PER
ONLY AND
EMC2/Y2
SETTINGS
YES
FAN MOTOR
ECM2/Y2 RPM SET PER
ONLY
YES
LED CONTINUOUS FAST
FLASH
LED CONSTANT ON
JUMPER
SETTINGS
JUMPER
JUMPER
SETTINGS
Page 44
REPLACE FAN MOTOR
CONTROL BOARD
REPLACE FAN MOTOR
CONTROL BOARD
LED STAGE INDICATOR:
ONE SLOW FLASH AND
ONE SHORT PAUSE
LED RPM INDICATOR:
EXAMPLE: (2−TON) – 5
SLOW FLASHES AND
LONG PAUSE
LED STAGE INDICATOR:
TWO SLOW FLASHES
AND ONE SHORT PAUSE
LED RPM INDICATOR:
EXAMPLE: (2−TON) – 5
SLOW FLASHES AND
LONG PAUSE
LED STAGE INDICATOR:
THREE SLOW FLASHES
AND ONE SHORT PAUSE
LED RPM INDICATOR:
EXAMPLE: (2−TON – 3
SLOW FLASHES AND
LONG PAUSE