Lennox Signature XP21 Series Installation And Service Procedure page 25

XP21 Two−Stage
Heat Pump Control
W
L
Y2
Y1
O
DS
2
C
5
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
47W97) required and ordered separately.
3. Cut on−board link W951 (clippable wire) from R−O HEAT PUMP for heat pump applications.
4. Cut on−board link W915 (clippable wire) for two−stage operation.
5. Cut loop jumper (clippable wire) Short DS to R for Humiditrol
must be installed between the DS terminals on the furnace and outdoor unit controls. See table 17 for fan speed based on unit capacity.
6. Cut on−board link (clippable wire) DS−R for Humiditrol
setting. See furnace installation instruction or engineering handbook for lowest fan speed information.
NOTE − For defrost temper with furnace, the optional 67M41 temper kit would be wired between W of from the heat pump control (A175) to the W1
of the furnace control The kit allows for the furnace to cycle on and off during a defrost. It protects the compressor from high refrigeration pressures
during defrost.
Figure 14. ComfortSense® 7000 Series Thermostat
Furnace Control
ComfortSense[ 7000 Thermostats
6
DS
O
3
L
H
DH
R
C
Y1
4
Y2
G
W3
W2
W1
®
7000 − catalog number Y0349 only. Resistor Kit (catalog number
®
applications. This will slow the outdoor unit's fan speed to a specific RPM. A wire
or Harmony IIIt applications. This will slow the indoor blower motor to the lowest speed
®
Page 25
Catalog # Y0349 or Y2081
R
G
W2
W1
O
L
H
D
B
Y2
1
Y1
C
T
T
Furnace/Two−Stage Heat Pump
On−board link
Low voltage thermostat
wiring
XP21