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To engage the continuous blower operation, place the
fan switch on the thermostat into the ON position. A call
for fan from the thermostat closes R to G on the ignition
control board. The control waits for a 1 second thermo-
stat debounce delay before responding to the call for
fan by ramping the circulating blower up to the cooling
speed. When the call for continuous fan is satisfied, the
control immediately ramps down the circulating blower.
Call for Fan
G
G − Fan Switch ON
g
− Fan Switch OFF
C
A
L
L
* Percentage of High Stage Cooling
FIGURE 32
Single Stage Cooling FIGURE 33
A call for cooling from the thermostat closes the R to Y
circuit on the integrated ignition/blower control board.
The control waits for a 1-second delay before energiz-
ing the circulating blower to 82% of the selected cool-
ing CFM (passive dehumidification mode). After 7.5
minutes, the circulating blower automatically ramps
up to 100% of the selected cooling airflow. When the
call for cooling is satisfied, the circulating blower ramps
back down to 82% of the selected cooling airflow for 45
seconds, then shuts off.
Single Stage Cooling
Y
7.5 minutes
82%
Y − Cool Demand Present
y
− Cool Demand Satisfied
C
A
L
L
FIGURE 33
g
38%*
O
F
F
y
45
100%
Sec
82%
O
F
F
Two Stage Cooling FIGURE 34
A call for 1st stage cooling from the thermostat closes
the R to Y circuit on the control board. The control waits
for a 1- second delay before energizing the circulating
blower. The blower motor runs at 57% of the selected
air flow for the first 7.5 minutes of the 1st stage cool-
ing demand (passive dehumidification mode). After 7.5
minutes, the blower motor runs at 70% of the selected
cooling air flow until 1st stage cooling demand is sat-
isfied.
A call for 2nd stage cooling from the thermostat closes
the R to Y2 circuit on the control board. The blower mo-
tor ramps up to 100% of the selected cooling air flow.
When the demand for cooling is met, the blower ramps
down to Y1 until satisfied, then ramps down to 57% for
45 secods, then turns off.
Y1
7.5
minutes 70%*
57%*
C
A
L
L
Y1 − 1 Stage Cool Demand Present
Y2 − 2 Stage Cool Demand Present
y2
* Percentage of High Stage Cooling
Heat Pump
For heat pump operation, clip the R-O link located next
to the terminal block at the bottom of the furnace con-
trol. In heat pump mode, a call for heat will result in the
circulating air blower operating at the selected cooling
airflow after a brief ramp-up period.
Page 28
Two Stage Cooling
/
/
Y1
Y2
Y1 y2
y1
100%*
70%*
1
min
57%
y1
st
y1
−
1 Stage Cool
st
Demand Satisfied
nd
nd
− 2
Stage Cool
Demand Satisfied
FIGURE 34
45
Sec.
57%*
O
F
F
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