Lennox XP21 Series Installation Instructions Manual page 26

HEAT PUMP
CONTROL (A175)
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) DS to R on two−stage units for Humiditrol
outdoor unit's fan speed to a specific RPM. A wire must be installed between the DS terminals on the furnace and outdoor unit controls. See table
15 for fan speed based on unit capacity.
6. Cut on−board link (clippable wire) DS−R for Humiditrol
will slow the indoor blower motor to the lowest speed 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 18. ComfortSense
506601−01
INTEGRATED
FURNACE CONTROL
(A95)
DS
O
6
L
H
3
DH
R
C
Y1
4
Y2
G
W2
W1
®
®
whole−home dehumidication system applications. This will slow the
®
whole−home dehumidication system or Harmony IIIt zoning system applications. This
®
7000 Series Thermostat
Page 26
INDOOR
THERMOSTAT (S1)
R
G
W2
W1
O
L
H
D
B
Y2
Y1
C
T
T
7000 − catalog number Y0349 only. Resistor kit (catalog number
Furnace/Two−Stage Heat Pump
On−board link
Low voltage
thermostat wiring
1