Lennox XP21 Series Installation Instructions

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Y1
O
R
W1
G
D
R
Y1
L
C
C
HEAT PUMP
CONTROL (A175)
B
Y2
Y2
W
O
DS
L
T
T
W2
H
H
O
C
L
Y2
DS
DH
G
R
Y1
W2
W1
1
2
3
4
6
5
On−board link
Low voltage
thermostat wiring
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
®
7000 − catalog number Y0349 only. Resistor kit (catalog number
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
®
whole−home dehumidication system applications. This will slow the
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
®
whole−home dehumidication system or Harmony IIIt zoning system applications. This
will slow the indoor blower motor to the lowest speed setting. See furnace installation instruction or engineering handbook for lowest fan speed
information.
INTEGRATED
FURNACE CONTROL
(A95)
INDOOR
THERMOSTAT (S1)
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
®
7000 Series Thermostat  Furnace/Two−Stage Heat Pump

Lennox XP21 Series Specifications

General

Brand	Lennox
Model	XP21 Series
Category	Heat Pump
Language	English