Lennox XC21 Installation Instructions Manual page 14

STEP 5 −− ELECTRICAL (Continued) −− Field Control Wiring
The following two illustrations provide examples of control wiring connections when using a non−communicating thermostat.
For examples of control wiring in complete or partial communicating systems, see the icomfortt−enabled thermostat Quick
Start Guide which is provided with the thermostat.
XC21 Two−Stage
Air Conditioner Control
W
L
Y2
Y1
O
DS
C
2
6
R
1. Thermostat T terminals are used for outdoor sensor input. Use for thermostat's outdoor temperature display (optional).
2. R to L connection is required for this model when using the ComfortSense
required and ordered separately.
3. Air handler control ships from factory with metal jumpers installed across W1, W2 and W3. For one−stage electric heat, do not remove factory
installed metal jumpers.
4. Air handler control ships from factory with metal jumpers installed across W1, W2 and W3. For two−stage electric heat, remove factory installed metal
jumper between W1 to W2. Then connect thermostat wire between the air handler control's W2 and the thermostat's W2 terminal.
5. Cut on−board link (clippable wire) from Y1−Y2 2 STAGE COMPR for two−stage compressor and two−speed fan operation.
6. Cut loop jumper (clippable wire) DS to R on two−stage units for Humiditrol
RPM. A wire must be installed between the DS terminals on the air handler and outdoor unit controls.
7. Cut on−board link (clippable wire) DS−R for Humiditrol
setting. See air handler installation instruction or engineering handbook for lowest fan speed information.
Air Handler
7
DS
O
L
H
DH
R
C
Y1
5
Y2
G
W3
3
W2
4
W1
®
7000 − catalog number Y0349 only. Resistor Kit (catalog number 47W97)
®
applications. This will slow the outdoor unit's fan speed to a specific
®
or Harmony IIIt applications. This will slow the indoor blower motor to the lowest speed
FIGURE 15
Page 14
ComfortSense[ 7000 Thermostats
Catalog # Y0349 or Y2081
R
G
W2
W1
O
L
H
D
B
Y2
Y1
C
T
T
On−board link
Low voltage thermostat
wiring
Flat metal jumper
1