Lennox XP21 Series User manual

06/11 506601−01
*2P0611* *P506601-01*
Page 1
E20 Lennox Industries Inc.
Dallas, Texas, USA
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
NOTICE TO INSTALLER
It is critical for proper defrost operation to set the defrost termination
pins (E47) on the heat pump control prior to starting system. See
Defrost System section on page 33 for further details.
DEFROST OPERATION
UNIT PLACEMENT
It is critical for proper unit operation to place outdoor unit on an
elevated surface as described in Unit Placement section on page 7.
BRAZING LINE SET TO SERVICE VALVES
It is imperative to follow the brazing technique illustrated starting on
page 13 to avoid damaging the service valve’s internal seals.
NOTICE
A thermostat is not included and must be ordered
separately.
DThe Lennox icomfort Touch®thermostat must be used
in communicating application
DIn non−icomforttapplications, the Lennox
ComfortSense®7000 thermostat may be used, as well
as other non−communicating thermostats.
In all cases, setup is critical to ensure proper system
operation.
Field wiring examples for non−icomforttapplications
begin on page 25.
See the icomfort Touch®thermostat Quick Start Guide
for communicating and partial communicating field
wiring connections.
INSTALLATION
INSTRUCTIONS
Dave Lennox Signature®
Collection XP21 System
HEAT PUMPS
506601−01
06/11
Supersedes 05/11
TABLE OF CONTENTS
General 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Model Number Identification 2. . . . . . . . . . . . . . . . . . . .
Typical Unit Parts Arrangement 3. . . . . . . . . . . . . . . . .
Shipping and Packing List 4. . . . . . . . . . . . . . . . . . . . . .
Using Manifold Gauge Set 4. . . . . . . . . . . . . . . . . . . . . .
Operating Service Valves 4. . . . . . . . . . . . . . . . . . . . . . .
Recovering Refrigerant from Existing System 6. . . . .
Unit Placement 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removing and Installing Panels 9. . . . . . . . . . . . . . . . .
New or Replacement Line Set 11. . . . . . . . . . . . . . . . . . .
Brazing Connections 13. . . . . . . . . . . . . . . . . . . . . . . . . . .
Flushing Line Set and Indoor Coil 16. . . . . . . . . . . . . . . .
Installing Indoor Expansion Valve 17. . . . . . . . . . . . . . . .
Leak Test Line Set and Indoor Coil 18. . . . . . . . . . . . . . .
Evacuating Line Set and Indoor Coil 18. . . . . . . . . . . . .
Electrical 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heat Pump Control (A175) Jumpers and Terminals 23
Field Control Wiring 25. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Servicing Unit Delivered Void of Charge 27. . . . . . . . . .
Unit Start−Up 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Refrigerant 27. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Handler / Coil Match up and Targeted
Subcooling Values 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating and Temperature Pressures 31. . . . . . . . . . .
System Operations 32. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Defrost System 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Status, Fault and Lockout LED Codes 43. . . . .
Field Component Configuration and Testing 48. . . . . . .
Maintenance (Dealer and Homeowner) 55. . . . . . . . . . .
SunSource®Home Energy System 57. . . . . . . . . . . . . .
Checklists 57. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General
This outdoor unit is designed for use with HFC−410A
refrigerant only. This unit must be installed with an
approved indoor air handler or coil. See the Lennox XP21
Engineering Handbook for approved indoor component
match ups.
Litho U.S.A.

Page 2
506601−01
Unit Dimensions −− Inches (mm)
39−1/2
(1003)
1 (25)
LIQUID LINE
INLET
SIDE VIEW ACCESS VIEW
DISCHARGE AIR
4−5/8
(117)
BASE WITH ELONGATED LEGS
16−7/8
(429)
8−3/4
(222)
26−7/8
(683)
3−3/4 (95)
30−3/4
(781)
3−1/8
(79)
SUCTION LINE
INLET
UNIT SUPPORT
FEET
35−1/2
(902)
18−1/2
(470)
8 (203)
4−1/2
(114)
ELECTRICAL INLET
(HIGH VOLTAGE)
37 (940) (−024 AND −036)
SOLAR MODULE
WIRING
ELECTRICAL INLET
(CONTROL WIRING −
LOW VOLTAGE)
47 (1194) (−048 AND −060)
Model Number Identification
P 21 036− −
Unit Type
P = Heat Pump
Series
Nominal Cooling Capacity
024 = 2 tons
036 = 3 tons
048 = 4 tons
060 = 5 tons
Minor Revision Number
230
Voltage
230 = 208/230V−1ph−60hz
Refrigerant Type
X = R−410A
X−2

Page 3
XP21 SERIES
Typical Unit Parts Arrangement
GROUND LUGS
HIGH VOLTAGE FIELD
CONNECTIONS
CONTACTOR  1 POLE (K1−1)
HEAT PUMP CONTROL
(A175) CAPACITOR (C12)
FAN MOTOR CONTROL (A177)
WIRE TIE
OUTDOOR AMBIENT
TEMPERATURE
SENSOR (RT13)
VAPOR VALVE
AND GAUGE
PORT
REVERSING
VALVE
LIQUID LINE BI−FLOW
FILTER DRIER HIGH PRESSURE
SWITCH (S4)
LIQUID VALVE AND
GAUGE PORT
TRUE SUCTION LINE
PORT
LOW PRESSURE
SWITCH (S87)
CRANKCASE HEATER THERMOSTAT (S40)
CRANKCASE HEATER (HR1)
(BELLY BAND)
COMPRESSOR
MUFFLER
DISCHARGE LINE
CHECK
EXPANSION VALVE
DISCHARGE LINE
TEMPERATURE SENSOR
(RT28)
COIL TEMPERATURE SENSOR (RT21) 
ON RETURN BEND, 12 TUBES UP FROM
BOTTOM (11.50’ UP)
XP21−024 AND −036
XP21−048 AND −060
COIL TEMPERATURE
SENSOR (RT21)  ON
RETURN BEND, 24
TUBES UP FROM
BOTTOM (23.50’ UP)
DISTRIBUTOR
Figure 1. Plumbing, Switches and Sensor Components

Page 4
506601−01
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause personal injury, loss of life, or
damage to property.
Installation and service must be performed by a licensed
professional installer (or equivalent) or a service agency.
CAUTION
Physical contact with metal edges and corners while
applying excessive force or rapid motion can result in
personal injury. Be aware of, and use caution when
working near these areas during installation or while
servicing this equipment.
IMPORTANT
The Clean Air Act of 1990 bans the intentional venting of
refrigerant (CFCs, HCFCs AND HFCs) as of July 1,
1992. Approved methods of recovery, recycling or
reclaiming must be followed. Fines and/or incarceration
may be levied for noncompliance.
WARNING
Electric Shock Hazard. Can cause injury
or death. Unit must be grounded in
accordance with national and local
codes.
Line voltage is present at all components
when unit is not in operation on units with
single-pole contactors. Disconnect all
remote electric power supplies before
opening access panel. Unit may have
multiple power supplies.
IMPORTANT
This model is designed for use in check expansion valve
systems only. An indoor expansion valve approved for
use with HFC−410A refrigerant must be ordered
separately, and installed prior to operating the system.
Shipping and Packing List
Check unit for shipping damage. Consult last carrier
immediately if damage is found.
1  Assembled outdoor unit.
1  Bag assembly which includes the following:
1  Bushing (for low voltage wiring)
2  Isolation grommets for liquid and suction lines
Using Manifold Gauge Set
When checking the system charge, only use a manifold
gauge set that features low−loss anti−blow back fittings.
IMPORTANT
To prevent stripping of the various caps used, the
appropriately sized wrench should be used and fitted
snugly over the cap before tightening.
Manifold gauge set used with HFC−410A refrigerant
systems must be capable of handling higher system
operating pressures. The gauges should be rated for use
with pressures of 0 − 800 psig on the high side and a low
side of 30" vacuum to 250 psig with dampened speed to
500 psi. Gauge hoses must be rated for use at or up to 800
psig of pressure with a 4000 psig burst rating.
Table 1. Torque Requirements
Parts Recommended Torque
Service valve cap 8 ft.− lb. 11 NM
Sheet metal screws 16 in.− lb. 2 NM
Machine screws #10 28 in.− lb. 3 NM
Compressor bolts 90 in.− lb. 10 NM
Gauge port seal cap 8 ft.− lb. 11 NM
Operating Service Valves
The liquid and vapor line service valves are used for
removing refrigerant, flushing, leak testing, evacuating,
verifying charge and charging.
Each valve is equipped with a service port which has a
factory−installed valve stem. Figure 2 provides information
on how to access and operating both angle and ball service
valves.
IMPORTANT
Only use Allen wrenches of sufficient hardness (50Rc −
Rockwell Harness Scale minimum). Fully insert the
wrench into the valve stem recess.
Service valve stems are factory−torqued (from 9 ft−lbs for
small valves, to 25 ft−lbs for large valves) to prevent
refrigerant loss during shipping and handling. Using an
Allen wrench rated at less than 50Rc risks rounding or
breaking off the wrench, or stripping the valve stem
recess.
See the Lennox Service and Application Notes #C−08−1
for further details and information.

Page 5
XP21 SERIES
(VALVE STEM SHOWN
CLOSED) INSERT HEX
WRENCH HERE
SERVICE PORT CORE
SERVICE PORT CAP
ANGLE−TYPE SERVICE VALVE
(FRONT−SEATED CLOSED)
TO OUTDOOR UNIT
STEM CAP
(VALVE STEM SHOWN OPEN)
INSERT HEX WRENCH HERE
TO INDOOR
UNIT
ANGLE−TYPE SERVICE VALVE
(BACK−SEATED OPENED)
BALL (SHOWN
CLOSED)
SERVICE PORT
CORE
TO INDOOR UNIT
TO OUTDOOR
UNIT
TO OPEN ROTATE STEM
COUNTERCLOCKWISE 90°.
TO CLOSE ROTATE STEM
CLOCKWISE 90°.
SERVICE PORT
SERVICE PORT
CAP
STEM CAP
VALVE
STEM
SERVICE VALVES ANGLE AND BALL
Operating Angle Type Service Valve:
1. Remove stem cap with an appropriately sized wrench.
2. Use a service wrench with a hex−head extension (3/16" for liquid line valve sizes and 5/16" for vapor line valve sizes) to back
the stem out counterclockwise as far as it will go.
Operating Ball Type Service Valve:
1. Remove stem cap with an appropriately sized wrench.
2. Use an appropriately sized wrenched to open. To open valve,
rotate stem counterclockwise 90°. To close, rotate stem
clockwise 90°.
12
3
4
5
6
7
8
9
10
11 12
1/12 TURN
To Access Service Port:
A service port cap protects the service port core from contamination and
serves as the primary leak seal.
1. Remove service port cap with an appropriately sized wrench.
2. Connect gauge set to service port.
3. When testing is completed, replace service port cap and tighten as
follows:
SWith torque wrench: Finger tighten and
torque cap per table 1.
SWithout torque wrench: Finger tighten and
use an appropriately sized wrench to turn
an additional 1/6 turn clockwise.
12
3
4
5
6
7
8
9
10
11 12
1/6 TURN
WHEN SERVICE VALVE IS CLOSED,THE SERVICE PORT IS OPEN
TO THE LINE SET AND INDOOR UNIT.
When service valve is OPEN, the service port is
open to linE set, indoor and outdoor unit.
Reinstall Stem Cap:
Stem cap protects the valve stem from damage and serves as the
primary seal. Replace the stem cap and tighten as follows:
SWith Torque Wrench: Finger tighten and then
torque cap per table 1.
SWithout Torque Wrench: Finger tighten and use
an appropriately sized wrench to turn an addi-
tional 1/12 turn clockwise.
NOTE  A label with specific torque requirements may be affixed to the stem cap. If the label is present, use the specified torque.
Figure 2. Angle and Ball Service Valves

Page 6
506601−01
Recovering Refrigerant from Existing System
SERVICE DISCONNECT
SWITCH
Disconnect all power to the existing outdoor unit at the disconnect
switch or main fuse box/breaker panel.
DISCONNECT POWER CONNECT MANIFOLD GAUGE SET
MANIFOLD GAUGES
RECOVERY MACHINE
CLEAN RECOVERY
CYLINDER
OUTDOOR UNIT
HIGH
LOW
Connect a gauge set, clean recovery cylinder and a recovery
machine to the service ports of the existing unit. Use the
instruction provided with the recovery machine to make the
connections.
METHOD 1:
Us this method if the existing outdoor unit is not equipped with shut−off valves, or if the unit is not operational and you plan to use the existing
HCFC−22 to flush the system.
Remove all HCFC−22 refrigerant from the existing system. Check gauges after shutdown to confirm that the entire system is completely void of
refrigerant.
METHOD 2:
Use this method if the existing outdoor unit is equipped with manual shut−off valves, and you plan to use new HCFC−22 refrigerant to flush the
system.
The following devices could prevent full system charge recovery into the outdoor unit:
SOutdoor unit’s high or low−pressure switches (if applicable) when tripped can cycle the compressor OFF.
SCompressor can stop pumping due to tripped internal pressure relief valve.
SCompressor has internal vacuum protection that is designed to unload the scrolls (compressor stops pumping) when the pressure ratio meets
a certain value or when the suction pressure is as high as 20 psig. (Compressor suction pressures should never be allowed to go into a vacuum.
Prolonged operation at low suction pressures will result in overheating of the scrolls and permanent damage to the scroll tips, drive bearings and
internal seals.)
Once the compressor can not pump down to a lower pressure due to one of the above system conditions, shut off the vapor valve. Turn OFF the
main power to unit and use a recovery machine to recover any refrigerant left in the indoor coil and line set.
Perform the following task:
AStart the existing HCFC−22 system in the cooling mode and close the liquid line valve.
BUse the compressor to pump as much of the existing HCFC−22 refrigerant into the outdoor unit until the outdoor system is full (high pressure
switch will trip and shut the compressor off). Turn the outdoor unit main power OFF and use a recovery machine to remove the remaining refriger-
ant from the system.
NOTE  It may be necessary to bypass the low pressure switch (if equipped) to ensure complete refrigerant evacuation.
CWhen the low side system pressures reach 0 psig, close the vapor line valve.
DCheck gauges after shutdown to confirm that the valves are not allowing refrigerant to flow back into the low side of the system.
Remove existing HCFC−22 refrigerant using one of the following methods
below:
RECOVERING REFRIGERANT
IMPORTANT  Some system configurations may contain higher than normal refrigerant charge due to either large internal coil volumes, and/or
long line sets.
12
3
Figure 3. Refrigerant Recovery Procedure

Page 7
XP21 SERIES
CONTROL PANEL
ACCESS
LOCATION
6 (152)
36 (914)
12 (305) 30 (762)
LINE SET
CONNECTIONS
24 (610)
LINE SET
CONNECTIONS
ACCESS PANEL
REAR VIEW OF UNIT
48 (1219)
MINIMUM CLEARANCE BETWEEN
TWO UNITS
CLEARANCE ON ALL SIDES  INCHES (MILLIMETERS)
ACCESS PANEL
MINIMUM CLEARANCE
ABOVE UNIT
NOTES:
SClearance to one of the other three
sides must be 36 inches (914mm).
SClearance to one of the remaining
two sides may be 12 inches
(305mm) and the final side may be
6 inches (152mm).
Figure 4. Mandatory Installation Clearances
Unit Placement
CAUTION
In order to avoid injury, take proper precaution when
lifting heavy objects.
See Unit Dimensions on page 3 for sizing mounting slab,
platforms or supports. Refer to figure 4 for mandatory
installation clearance requirements.
POSITIONING CONSIDERATIONS
Consider the following when positioning the unit:
SSome localities are adopting sound ordinances based
on the unit’s sound level registered from the adjacent
property and not from the installation property. Install
the unit as far as possible from the property line.
SWhen possible, do not install the unit directly outside
a window. Glass has a very high level of sound
transmission. For proper placement of unit in relation
to a window see the provided illustration in figure 5,
detail A.
PLACING UNIT ON SLAB
When installing unit at grade level, the top of the slab
should be high enough above grade so that water from
higher ground will not collect around the unit. The slab
should have a slope tolerance as described in figure 5,
detail B.
NOTE  If necessary for stability, anchor unit to slab as
described in figure 5, detail D.
ELEVATING THE UNIT
Units are outfitted with elongated support feet as illustrated
in figure 5, detail C.
If additional elevation is necessary, raise the unit by
extending the height of the unit support feet. This may be
achieved by using a 2−inch (50.8mm) Schedule 40 female
threaded adapter.
The specified coupling will fit snuggly into the recessed
portion of the feet. Use additional 2−inch (50.8mm)
Schedule 40 male threaded adaptors which can be
threaded into the female threaded adaptors to make
additional adjustments to the level of the unit.
NOTE  Keep the height of extenders short enough to
ensure a sturdy installation. If it is necessary to extend
further, consider a different type of field−fabricated
framework that is sturdy enough for greater heights.

Page 8
506601−01
LEG DETAIL
BASE
2" (50.8MM) SCH 40
FEMALE THREADED
ADAPTER
Concrete slab  use two plastic anchors (hole
drill 1/4")
Wood or plastic slab  no plastic anchor (hole
drill 1/8")
COIL
BASE PAN
CORNER POST
STABILIZING BRACKET (18 GAUGE
METAL  2" WIDTH; HEIGHT AS
REQUIRED)
 Slab Side Mounting
#10 1/2" LONG SELF−DRILLING
SHEET METAL SCREWS
#10 1−1/4" LONG HEX HD SCREW
AND FLAT WASHER
MINIMUM ONE
PER SIDE
Stabilizing bracket (18 gauge metal  2" (50.8mm) width; height as required); bend to form
right angle as exampled below.
FOR EXTRA
STABILITY
 Deck Top Mounting
 Elevated Slab Mounting
using Feet Extenders
STABILIZING UNIT ON UNEVEN SURFACES
Install unit level or, if on a slope, maintain slope tolerance of two (2)
degrees (or two inches per five feet [50 mm per 1.5 m]) away from
building structure.
MOUNTING
SLAB
BUILDING
STRUCTURE
GROUND LEVEL
 Outside Unit Placement  Slab Mounting at Ground Level
SAME FASTENERS AS
SLAB SIDE MOUNTING.
IMPORTANT  To help stabilize an outdoor unit, some installations may require strapping the unit to the pad using brackets and anchors
commonly available in the marketplace.
DETAIL A DETAIL B
DETAIL C
DETAIL D
2" (50.8MM) SCH 40
MALE THREADED
ADAPTER
Use additional 2" SCH 40 male threaded adapters
which can be threaded into the female threaded
adapters to make additional adjustments to the level of
the unit.
TWO 90° ELBOWS INSTALLED IN LINE SET WILL
REDUCE LINE SET VIBRATION.
Install unit away from windows.
One bracket per side (minimum). For extra stability, two brackets per side, two inches
(51mm) from each corner.
DETAIL E
Figure 5. Placement and Slab Mounting

Page 9
XP21 SERIES
STABILIZING UNIT ON UNEVEN SURFACES
IMPORTANT
Unit Stabilizer Bracket Use (field−provided):
Always use stabilizers when unit is raised above the
factory height. (Elevated units could become unstable in
gusty wind conditions).
Stabilizers may be used on factory height units when
mounted on unstable an uneven surface.
1. Remove two side louvered panels to expose the unit
base.
2. Install the brackets as illustrated in figure 5, details D
or E using conventional practices.
3. Replace the panels after installation is complete.
ROOF MOUNTING
Install the unit a minimum of six (6) inches (152 mm) above
the roof surface to avoid ice build−up around the unit.
Locate the unit above a load bearing wall or area of the roof
that can adequately support the unit. Consult local codes
for rooftop applications.
If unit coil cannot be mounted away from prevailing winter
winds, a wind barrier should be constructed. Size barrier at
least the same height and width as outdoor unit. Mount
barrier 24 inches (610 mm) from the sides of the unit in the
direction of prevailing winds.
24"
(610)
WIND BARRIER
PREVAILING WINTER
WINDS
INLET AIR
INLET AIR
INLET AIR
Figure 6. Rooftop Application and Wind Barrier
NOTICE
Roof Damage!
This system contains both refrigerant and oil. Some
rubber roofing material may absorbed oil and cause the
rubber to swell when it comes into contact with oil. The
rubber will then bubble and could cause leaks. Protect
the roof surface to avoid exposure to refrigerant and oil
during service and installation. Failure to follow this
notice could result in damage to roof surface.
Removing and Installing Panels
IMPORTANT
Do not allow panels to hang on unit by top tab. Tab is for
alignment and not designed to support weight of panel.
IMPORTANT
To help stabilize an outdoor unit, some installations may
require strapping the unit to the pad using brackets and
anchors commonly available in the marketplace.
WARNING
To prevent personal injury, or damage to panels, unit or
structure, be sure to observe the following:
While installing or servicing this unit, carefully stow all
removed panels out of the way, so that the panels will not
cause injury to personnel, nor cause damage to objects
or structures nearby, nor will the panels be subjected to
damage (e.g., being bent or scratched).
While handling or stowing the panels, consider any
weather conditions, especially windy conditions, that
may cause panels to be blown around and battered.

Page 10
506601−01
REMOVE 4 SCREWS TO
REMOVE PANEL FOR
ACCESSING COMPRESSOR
AND CONTROLS.
Position panel with holes aligned;
install screws and tighten.
Detail A
Detail B
ROTATE IN THIS DIRECTION; THEN
DOWN TO REMOVE PANEL
SCREW
HOLES
LIP
Panel shown slightly rotated to allow top tab to exit (or enter) top slot for removing (or
installing) panel.
Maintain minimum panel angle (as close
to parallel with the unit as possible)
while installing panel.
PREFERRED ANGLE FOR INSTALLATION
Detail D
ANGLE MAY BE TOO EXTREME HOLD DOOR FIRMLY ALONG
THE HINGED SIDE TO MAINTAIN
FULLY−ENGAGED TABS
LOUVERED PANEL REMOVAL
Remove the louvered panels as follows:
1. Remove two screws, allowing the panel to swing open slightly.
2. Hold the panel firmly throughout this procedure Rotate bottom corner of panel away
from hinged corner post until lower three tabs clear the slots as illustrated in detail
B.
3. Move panel down until lip of upper tab clears the top slot in corner post as illustrated
in detail A.
LOUVERED PANEL INSTALLATION
Position the panel almost parallel with the unit as illustrated in detail D with the screw side
as close to the unit as possible. Then, in a continuous motion:
1. Slightly rotate and guide the lip of top tab inward as illustrated in detail A and C; then
upward into the top slot of the hinge corner post.
2. Rotate panel to vertical to fully engage all tabs.
3. Holding the panel’s hinged side firmly in place, close the right−hand side of the panel,
aligning the screw holes.
4. When panel is correctly positioned and aligned, insert the screws and tighten.
REMOVING AND INSTALLING
PANELS
WARNING
Detail C
Figure 7. Removing and Installing Panels