Control Box - Lennox Signature XP21 Series Installation And Service Procedure

FAN MOTOR CONTROL (A177)
PULSE−WIDTH MODULATION (PWM)

CONTROL BOX

HEAT PUMP
CONTROL (A175)
VERIFY DC VOLTAGE OUTPUT USING FAN PWM OUT AND
COM TERMINALS. SEE TABLE 17 FOR OPTIMAL DC
VOLTAGE BASED ON CFM PROFILE USED.
GREEN
RED
RED
YELLOW
YELLOW
YELLOW
Figure 21. Fan Motor Control, Wiring, Jumper Settings, Testing and LED Location
J2
COM
FAN PWM OUT
HIGH PRESSURE SWITCH (S4)
HEAT PUMP CONTROL
Page 41
CFM Profile Pin Select
JUMPER
JUMPER
OFF
ON
J2
YELLOW
BLUE
BLACK
YELLOW
YELLOW
FAN MOTOR
CONTROL
SEE TABLE 17 FOR CFM PROFILE
SELECTION OPTIONS.
LED
GREEN
RED
RED
B4 FAN
MOTOR
BLACK
BROWN
XP21