Lennox Signature XP21 Series Installation And Service Procedure page 40

DEMAND
BEGINS
MISMATCHED
RPM
CRC
FAILURE
ONE STAGE
(LOW)
NO
DEMAND
ENDED
TWO STAGE
(HIGH)
NO
DEMAND
ENDED
EDA
OPERATION
NO
DEMAND
ENDED
Figure 20. Fan Motor Control (A177) One/Two Stage and EDA LED Sequence of Operation
XP21
DEFAULT
FAN MOTOR
SPEED USED
DEFAULT FAN
MOTOR
SPEED USED
FAN MOTOR
ECM1/Y1 RPM SET PER
ONLY
SETTINGS
YES
FAN MOTOR
ECM1/Y1
RPM SET PER
ONLY AND
JUMPER
EMC2/Y2
SETTINGS
YES
FAN MOTOR
ECM2/Y2 RPM SET PER
ONLY JUMPER
SETTINGS
YES
LED CONTINUOUS FAST
FLASH
LED CONSTANT ON
JUMPER
Page 40
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