12
To Select the Same Speed for COOL and HEAT
NOTE: Some models have the same speed for COOL and HEAT
already connected.
At the Blower Motor Connector
1. Disconnect power.
2. Remove blower and burner access panels.
3. Place black wire on the HIGH, MED or LOW motor speed tap,
as desired.
4. Place blue wire on any of the other motor speed taps.
At the Furnace Control Board
1. Remove the blue and black wires from the HEAT and COOL
terminals and the black jumper wire from the UNUSED
terminal.
2. Connect the blue wire to the UNUSED terminal.
3. Connect the black jumper wire (piggyback end) to the COOL
terminal.
4. Connect the other end of the black jumper wire to the HEAT
terminal.
5. Connect the black wire to the black jumper wire (piggyback
end) on the COOL terminal.
6. Replace the blower and burner access panels.
7. Reconnect power.
To Select Different Speeds for COOL and HEAT
At the Blower Motor Connector
1. Disconnect power.
2. Remove blower and burner access panels.
3. Place black wire on the HIGH, MED or LOW motor speed tap,
as desired for COOLING.
4. Place blue wire on any of the other motor speed taps for
HEATING.
At the Unit Control Board
1. Place blue wire on the COOL terminal.
2. Place red wire on the HEAT terminal.
3. Replace blower and burner access panels.
4. Reconnect power.
Adjust Blower Speed Variable-Speed Motor Only
Circulation Airflow Adjustments
The controls include a variable-speed motor interface board. The
ADJUST tap can be used to raise (+) or lower (-) the airflow by
15 percent.
Heating and Cooling Airflows
The units are factory-set for the correct heating and cooling
airflows. However, airflow changes can be made by moving the
position of the HEAT and COOL taps. See Adjusting Airflow for
Variable-Speed Motor chart.
Continuous Blower
The comfort level of the living space can be enhanced when
using this feature by allowing continuous circulation of air
between calls for cooling or heating. The continuous circulation
of air occurs at half the full cooling airflow rate. To use this
feature, place the thermostat fan switch into the On position.
Cooling Airflow Ramp Up
At the beginning of a call for cooling, the blower will run at
80 percent of full airflow for 7.5 minutes. This improves the
system’s moisture removal and saves blower power during
cooling start.
Reduced Airflow Operation (Dehumidification)
For situations where humidity control is an issue, the variable-
speed motor can be connected to operate at a 25 percent
reduction in the normal airflow rate. The variable-speed motor
interface board provides for connection of a humidistat on the
HUM terminal. When a humidistat is connected, the dehumidifier
resistor on the interface must be cut. The humidistat should be
wired to open during high humidity, which will reduce blower
airflow.
ADJUST, HEAT, and COOL Taps and Dehumidify Resistor
Blower Speed Chart for Multi-Speed Motor
Unit
Factory-Shipped Settings
Cooling Input
Heating Input
Heat (BU)
Cool (BK)
24
68
MED
LOW
30
68
MED
MED
36
68
MED
HIGH
36
90
HIGH
HIGH
42
83
LOW
LOW
42
110
LOW
LOW
48
83
LOW
MED
48
110
LOW
MED
48
138
MED
MED
60
83
LOW
HIGH
60
110
LOW
HIGH
60
138
MED
HIGH
WARNING
Electrical Shock Hazard
Disconnect power before servicing.
Replace all parts and panels before operating.
Failure to do so can result in death or electrical shock.
A. Dehumidify LED
B. Dehumidify resistor
DEHUMIDIFY
CUT TO ENABLE
COOL
HEAT
ADJUST
NORM
A
B
C
D
A
B
C
D
(+)
(–)
TEST
D1
A
B
