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

Page 11
XP21 SERIES
New or Replacement Line Set
REFRIGERANT LINE SET
This section provides information on installation or
replacement of existing line set. If new or replacement line
set is not being installed then proceed to Brazing
Connections on page 13.
IMPORTANT
Lennox highly recommends changing line set when
converting the existing system from HCFC−22 to
HFC−410A.If that is not possible and the line set is the
proper size as reference in table 2, use the procedure
outlined under Flushing the System on page 16.
If refrigerant lines are routed through a wall, then seal and
isolate the opening so vibration is not transmitted to the
building. Pay close attention to line set isolation during
installation of any HVAC system. When properly isolated
from building structures (walls, ceilings. floors), the
refrigerant lines will not create unnecessary vibration and
subsequent sounds. See figure 8 for recommended
installation practices. Also, consider the following when
placing and installing a high−efficiency outdoor unit.
IMPORTANT
Refrigerant lines must not contact structure.
Liquid lines that meter the refrigerant, such as RFC1 liquid
lines, must not be used in this application. Existing line set
of proper size as listed in table 2 may be reused. If system
was previously charged with HCFC−22 refrigerant, then
existing line set must be flushed (see Flushing the System
on page 16).
Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit to the indoor unit coil (braze
connections). Use Lennox L15 (sweat, non−flare) series
line set, or field−fabricated refrigerant line sizes as listed in
table 2.
Table 2. Refrigerant Line Set
Models Liquid
Line
Vapor/
Suction
Line
L15 Line Set
−024, −036
and−048
3/8 (10) 7/8 (22) L15 line set sizes are
dependent on unit match up.
See XP21 Engineering
Handbook to determine
correct line set sizes.
−060 3/8 (10) 1−1/8 (29) Field Fabricated
NOTE  Some applications may required a field−provided 7/8" to
1−1/8" adapter.
NOTE  When installing refrigerant lines longer than 50
feet, see the Lennox Refrigerant Piping Design and
Fabrication Guidelines, or contact Lennox Technical
Support Product Applications for assistance.
To obtain the correct information from Lennox, be sure to
communicate the following information:
SModel (XP21) and size of unit (e.g. −036).
SLine set diameters for the unit being installed as listed
in table 2 and total length of installation.
SNumber of elbows vertical rise or drop in the piping.
The compressor is charged with sufficient Polyol Ester oil
(POE) for line set lengths up to 50 feet. Recommend
adding oil to system based on the amount of refrigerant
charge in the system. Systems with 20 pounds or less of
refrigerant required no oil to be added.
For systems over 20 pounds − add one ounce for every five
(5) pounds of HFC−410A refrigerant.
Recommended POE oils are Mobil EAL ARCTIC 22 CC or
ICI EMKARATEtRL32CF.
IMPORTANT
If this unit is being matched with an approved line set
or indoor unit coil which was previously charged with
mineral oil, or if it is being matched with a coil which
was manufactured before January of 1999, the coil
and line set must be flushed prior to installation. Take
care to empty all existing traps. Polyol ester (POE) oils
are used in Lennox units charged with HFC−410A
refrigerant. Residual mineral oil can act as an
insulator, preventing proper heat transfer. It can also
clog the expansion device, and reduce the system
performance and capacity.
Failure to properly flush the system per the
instructions below will void the warranty.
WARNING
Polyol Ester (POE) oils used with HFC−410A
refrigerant absorb moisture very quickly. It is very
important that the refrigerant system be kept closed
as much as possible. DO NOT remove line set caps
or service valve stub caps until you are ready to make
connections.
IMPORTANT
Mineral oils are not compatible with HFC−410A.If oil
must be added, it must be a Polyol Ester oil.

Page 12
506601−01
ANCHORED HEAVY NYLON
WIRE TIE OR AUTOMOTIVE
MUFFLER-TYPE HANGER
STRAP LIQUID LINE TO
VAPOR LINE
WALL
STUD
LIQUID LINE
NON−CORROSIVE
METAL SLEEVE
VAPOR LINE − WRAPPED
IN ARMAFLEX
AUTOMOTIVE
MUFFLER-TYPE HANGER
REFRIGERANT LINE SET  TRANSITION
FROM VERTICAL TO HORIZONTAL
Line Set Isolation  The following illustrations are examples of proper refrigerant line set isolation:
STRAPPING
MATERIAL (AROUND
VAPOR LINE ONLY)
TAPE OR
WIRE TIE
WIRE TIE (AROUND
VAPOR LINE ONLY)
FLOOR JOIST OR
ROOF RAFTER
TAPE OR
WIRE TIE
To hang line set from joist or rafter, use either metal strapping material
or anchored heavy nylon wire ties.
8 FEET (2.43 METERS)
STRAP THE VAPOR LINE TO THE JOIST
OR RAFTER AT 8 FEET (2.43 METERS)
INTERVALS THEN STRAP THE LIQUID
LINE TO THE VAPOR LINE.
FLOOR JOIST OR
ROOF RAFTER
REFRIGERANT LINE SET  INSTALLING
HORIZONTAL RUNS
NOTE  Similar installation practices should be used if line set is
to be installed on exterior of outside wall.
PVC
PIPE
FIBERGLASS
INSULATION
CAULK
OUTSIDE
WALL
VAPOR LINE WRAPPED
WITH ARMAFLEX
LIQUID
LINE
OUTSIDE WALL LIQUID LINE
VAPOR LINE
WOOD BLOCK
BETWEEN STUDS
STRAP
WOOD BLOCK
STRAP
SLEEVE
WIRE TIE
WIRE TIE
WIRE TIE
INSIDE WALL
REFRIGERANT LINE SET  INSTALLING
VERTICAL RUNS (NEW CONSTRUCTION SHOWN)
NOTE  Insulate liquid line when it is routed through areas where the
surrounding ambient temperature could become higher than the
temperatureof the liquid line or when pressure drop is equal to or greater
than 20 psig.
NON−CORROSIVE
METAL SLEEVE
NON−CORROSIVE
METAL SLEEVE
8 FEET (2.43 METERS)
Figure 8. Line Set Installation

Page 13
XP21 SERIES
Brazing Connections
Use the procedures outline in figures 9 and 10 for brazing
line set connections to service valves.
WARNING
Danger of fire. Bleeding the refrigerant
charge from only the high side may result
in pressurization of the low side shell and
suction tubing. Application of a brazing
torch to a pressurized system may result
in ignition of the refrigerant and oil
mixture − Check the high and low
pressures before applying heat.
WARNING
When using a high pressure gas such as
dry nitrogen to pressurize a refrigeration
or air conditioning system, use a
regulator that can control the pressure
down to 1 or 2 psig (6.9 to 13.8 kPa).
CAUTION
Brazing alloys and flux contain materials which are
hazardous to your health.
Avoid breathing vapors or fumes from brazing
operations. Perform operations only in well−ventilated
areas.
Wear gloves and protective goggles or face shield to
protect against burns.
Wash hands with soap and water after handling brazing
alloys and flux.
IMPORTANT
Connect gauge set low pressure side to vapor line
service valve and repeat procedure starting at
paragraph 4 for brazing the liquid line to service port
valve.
IMPORTANT
Allow braze joint to cool before removing the wet rag
from the service valve. Temperatures above 250ºF can
damage valve seals.
IMPORTANT
Use silver alloy brazing rods with 5% minimum silver
alloy for copper−to−copper brazing. Use 45% minimum
alloy for copper−to−brass and copper−to−steel brazing.
WARNING
Fire, Explosion and Personal Safety
Hazard.
Failure to follow this warning could
result in damage, personal injury or
death.
Never use oxygen to pressurize or
purge refrigeration lines. Oxygen,
when exposed to a spark or open
flame, can cause fire and/or an ex-
plosion, that could result in property
damage, personal injury or death.

Page 14
506601−01
ATTACH THE MANIFOLD GAUGE SET FOR BRAZING
LIQUID AND SUCTION / VAPOR LINE SERVICE VALVES
OUTDOOR
UNIT
LIQUID LINE
SUCTION / VAPOR
LINE
LIQUID LINE SERVICE
VALVE
SUCTION /
VAPOR LINE
SERVICE
VALVE
ATTACH
GAUGES
INDOOR
UNIT
SUCTION / VAPOR SERVICE PORT MUST BE
OPEN AND SERVICE PORT CORE REMOVED
TO ALLOW EXIT POINT FOR NITROGEN FLOW
AConnect gauge set low pressure side to liquid line
service valve (service port).
BConnect gauge set center port to bottle of nitrogen with
regulator.
CWith valve core removed from the suction / vapor line
service port, nitrogen flow will have an exit point.
NITROGEN
HIGHLOW
B
A
C
PIPING PANEL REMOVAL AND PREPARING LINE
SET
CAP AND CORE REMOVAL
Remove piping panel for easier access to service valves. Cut ends
of the refrigerant lines square (free from nicks or dents) and debur
the ends. The pipe must remain round. Do not crimp end of the line.
Remove service cap and core from both the suction / vapor and
liquid line service ports.
12
LIQUID LINE SERVICE VALVE
SERVICE PORT
CORE
SERVICE PORT CAP
SERVICE PORT
CORE
SERVICE
PORT CAP
CUT AND DEBUR
LINE SET SIZE MATCHES
SERVICE VALVE CONNECTION
COPPER TUBE
STUB
SERVICE VALVE
CONNECTION
REFRIGERANT LINE
DO NOT CRIMP SERVICE VALVE
CONNECTOR WHEN PIPE IS
SMALLER THAN CONNECTION
REDUCER
3
SUCTION / VAPOR LINE
SERVICE VALVE
LINE SET SIZE IS SMALLER
THAN CONNECTION
Figure 9. Brazing Procedures

Page 15
XP21 SERIES
BRAZE LINE SET
Water saturated cloths must remain water saturated throughout
the brazing and cool−down process.
6
After all connections have been brazed, disconnect manifold gauge set from service ports. Apply additional water saturated cloths to both services
valves to cool piping. Once piping is cool, remove all water saturated cloths. Refer to the unit installation instructions for the next step in preparing
the unit.
PREPARATION FOR NEXT STEP
7
WRAP SERVICE VALVES
To help protect service valve seals during brazing, wrap water saturated cloths around service valve bodies and copper tube stubs. Use
additional water saturated cloths underneath the valve body to protect the base paint.
4
FLOW NITROGEN
Flow regulated nitrogen (at 1 to 2 psig) through the refrigeration
gauge set into the valve stem port connection on the liquid service
valve and out of the suction / vapor valve stem port. See steps 3A, 3B
and 3C on previous page and below for manifold gauge setup.
5
SUCTION / VAPOR LINE
WHEN BRAZING LINE SET TO
SERVICE VALVES, POINT FLAME AWAY
FROM SERVICE VALVE.
WARNING
1. FIRE, PERSONAL INJURY, OR PROPERTY
DAMAGE will result if you do not wrap a water
saturated cloth around both liquid and suction line
service valve bodies and copper tube stub while
brazing in the line set! The braze, when complete,
must be quenched with water to absorb any residual
heat.
2. Do not open service valves until refrigerant lines and
indoor coil have been leak−tested and evacuated.
Refer to procedures provided in this supplement.
LIQUID LINE
WATER SATURATED
CLOTHS
WATER SATURATED CLOTHS
ABraze liquid line to liquid line service valve.
BBraze suction / vapor line to suction / vapor service
valve.
6A
6B
SUCTION / VAPOR SERVICE PORT
MUST BE OPEN AND SERVICE PORT
CORE REMOVED TO ALLOW EXIT
POINT FOR NITROGEN FLOW
IMPORTANT  Allow braze joint to cool. Apply
additional water saturated cloths to help cool
brazed joints. Do not remove water saturated
cloths until piping has cooled. Temperatures
above 250ºF will damage valve seals.
Figure 10. Brazing Procedures (Continued)

Page 16
506601−01
Flushing Line Set and Indoor Coil
The following procedure should not be performed on a system which contain contaminants (i.e., compressor burn out).
SENSING
LINE
TEFLON®RING
FIXED ORIFICE
BRASS NUT
LIQUID LINE ASSEMBLY
(INCLUDES STRAINER)
LIQUID LINE ORIFICE HOUSING
DISTRIBUTOR TUBES
DISTRIBUTOR
ASSEMBLY
REMOVE AND DISCARD
WHITE TEFLON®SEAL
(IF PRESENT)
AOn fully cased coils, remove the coil access and plumbing panels.
BRemove any shipping clamps holding the liquid line and distributor as-
sembly.
CUsing two wrenches, disconnect liquid line from liquid line orifice hous-
ing. Take care not to twist or damage distributor tubes during this pro-
cess.
DRemove and discard fixed orifice, valve stem assembly if present and
Teflon®washer as illustrated above.
EUse a field−provided fitting to temporary reconnect the liquid line to the
indoor unit’s liquid line orifice housing.
TYPICAL EXISTING FIXED ORIFICE
REMOVAL PROCEDURE (UNCASED
COIL SHOWN)
TYPICAL EXISTING EXPANSION VALVE REMOVAL
PROCEDURE (UNCASED COIL SHOWN)
TWO PIECE PATCH PLATE
(UNCASED COIL ONLY)
VAPOR
LINE
DISTRIBUTOR
ASSEMBLY
DISTRIBUTOR
TUBES
LIQUID
LINE
MALE EQUALIZER
LINE FITTING
EQUALIZER
LINE
CHECK
EXPANSION
VALVE
TEFLON®
RING
STUB END
TEFLON®
RING
SENSING BULB
LIQUID LINE
ORIFICE
HOUSING
LIQUID LINE
ASSEMBLY WITH
BRASS NUT
AOn fully cased coils, remove the coil access and plumbing panels.
BRemove any shipping clamps holding the liquid line and distributor
assembly.
CDisconnect the equalizer line from the check expansion valve
equalizer line fitting on the vapor line.
DRemove the vapor line sensing bulb.
EDisconnect the liquid line from the check expansion valve at the liquid
line assembly.
FDisconnect the check expansion valve from the liquid line orifice
housing. Take care not to twist or damage distributor tubes during this
process.
GRemove and discard check expansion valve and the two Teflon®rings.
HUse a field−provided fitting to temporary reconnect the liquid line to the
indoor unit’s liquid line orifice housing.
LOW HIGH
EXISTING
INDOOR
UNIT
GAUGE
MANIFOLD
INVERTED HCFC−22
CYLINDER CONTAINS
CLEAN HCFC−22 TO BE
USED FOR FLUSHING.
LIQUID LINE SERVICE
VALVE
INLET
DISCHARGE
TANK
RETURN
CLOSED
OPENED
RECOVERY
CYLINDER
RECOVERY MACHINE
NEW
OUTDOOR
UNIT
VAPOR LINE
SERVICE VALVE
VAPOR
LIQUID
1
AInverted HCFC−22 cylinder with clean refrigerant to the vapor service
valve.
BHCFC−22 gauge set (low side) to the liquid line valve.
CHCFC−22 gauge set center port to inlet on the recovery machine with an
empty recovery tank to the gauge set.
DConnect recovery tank to recovery machines per machine instructions.
CONNECT GAUGES AND EQUIPMENT FOR
FLUSHING PROCEDURE
A
B
C
D
B
OR
FLUSHING LINE SET
ASet the recovery machine for liquid recovery and start the
recovery machine. Open the gauge set valves to allow the
recovery machine to pull a vacuum on the existing system line
set and indoor unit coil.
BInvert the cylinder of clean HCFC−22 and open its valve to allow
liquid refrigerant to flow into the system through the vapor line
valve. Allow the refrigerant to pass from the cylinder and through
the line set and the indoor unit coil before it enters the recovery
machine.
CAfter all of the liquid refrigerant has been recovered, switch the
recovery machine to vapor recovery so that all of the HCFC−22
vapor is recovered. Allow the recovery machine to pull down to 0
the system.
DClose the valve on the inverted HCFC−22 drum and the gauge
set valves. Pump the remaining refrigerant out of the recovery
machine and turn the machine off.
The line set and indoor unit coil must be flushed with at least the
same amount of clean refrigerant that previously charged the
system. Check the charge in the flushing cylinder before
proceeding.
1A
2
3
1B
Figure 11. Flushing Line Set and Indoor Coil

Page 17
XP21 SERIES
Installing Indoor Expansion Valve
This outdoor unit is designed for use in systems that use check expansion valve metering device. See the Lennox XP21
Engineering Handbook for approved check expansion valve kit match−ups and application information. The check
expansion valve unit can be installed internal or external to the indoor coil. In applications where an uncased coil is being
installed in a field−provided plenum, install the check expansion valve in a manner that will provide access for field servicing
of the check expansion valve. Refer to below illustration for reference during installation of check expansion valve unit.
AAttach the vapor line sensing bulb in the proper
orientation as illustrated to the right using the clamp and
screws provided.
NOTE  Confirm proper thermal contact between vapor line
and check expansion bulb before insulating the sensing bulb
once installed.
BConnect the equalizer line from the check expansion
valve to the equalizer vapor port on the vapor line. Finger
tighten the flare nut plus 1/8 turn (7 ft−lbs) as illustrated
below.
TWO PIECE
PATCH PLATE
(UNCASED
COIL ONLY)
VAPOR
LINE
LIQUID LINE
ORIFICE
HOUSING
DISTRIBUTOR
TUBES
LIQUID LINE
MALE EQUALIZER LINE
FITTING (SEE
EQUALIZER LINE
INSTALLATION FOR
FURTHER DETAILS)
SENSING
LINE
EQUALIZER
LINE
CHECK
EXPANSION
VALVE
TEFLON®
RING
(Uncased Coil Shown)
Sensing bulb insulation is required if
mounted external to the coil casing. sensing
bulb installation for bulb positioning.
STUB
END
TEFLON®
RING
LIQUID LINE
ASSEMBLY WITH
BRASS NUT
DISTRIBUTOR
ASSEMBLY
ARemove the field−provided fitting that temporary
reconnected the liquid line to the indoor unit’s distributor
assembly.
BInstall one of the provided Teflon®rings around the
stubbed end of the check expansion valve and lightly
lubricate the connector threads and expose surface of
the Teflon®ring with refrigerant oil.
CAttach the stubbed end of the check expansion valve to
the liquid line orifice housing. Finger tighten and use an
appropriately sized wrench to turn an additional 1/2 turn
clockwise as illustrated in the figure above, or 20 ft−lb.
DPlace the remaining Teflon®washer around the other
end of the check expansion valve. Lightly lubricate
connector threads and expose surface of the Teflon®
ring with refrigerant oil.
EAttach the liquid line assembly to the check expansion
valve. Finger tighten and use an appropriately sized
wrench to turn an additional 1/2 turn clockwise as
illustrated in the figure above or 20 ft−lb.
ON 7/8" AND LARGER LINES,
MOUNT SENSING BULB AT
EITHER THE 4 OR 8 O’CLOCK
POSITION. NEVER MOUNT ON
BOTTOM OF LINE.
12
ON LINES SMALLER THAN
7/8", MOUNT SENSING
BULB AT EITHER THE 3 OR
9 O’CLOCK POSITION.
12
BULB
VAPOR LINE
VAPOR LINE
NOTE  NEVER MOUNT ON BOTTOM OF LINE.
BULB
BULB
BULB
VAPOR LINE
FLARE NUT
COPPER FLARE
SEAL BONNET
MALE BRASS EQUALIZER
LINE FITTING
FLARE SEAL CAP
OR
1
2
3
4
5
6
7
8
9
10
11 12
1/2 Turn
SENSING BULB INSTALLATION
EQUALIZER LINE INSTALLATION
1
2
3
4
5
6
7
8
9
10
11 12
1/8 Turn
ARemove and discard either the flare seal cap or flare nut
with copper flare seal bonnet from the equalizer line port
on the vapor line as illustrated in the figure to the right.
BRemove and discard either the flare seal cap or flare nut
with copper flare seal bonnet from the equalizer line port on
the vapor line as illustrated in the figure to the right.
INDOOR EXPANSION VALVE INSTALLATION
Figure 12. Installing Indoor Expansion Valve

Page 18
506601−01
IMPORTANT
The Environmental Protection Agency (EPA) prohibits
the intentional venting of HFC refrigerants during
maintenance, service, repair and disposal of appliance.
Approved methods of recovery, recycling or reclaiming
must be followed.
IMPORTANT
If this unit is being matched with an approved line set
or indoor unit coil which was previously charged with
mineral oil, or if it is being matched with a coil which
was manufactured before January of 1999, the coil
and line set must be flushed prior to installation. Take
care to empty all existing traps. Polyol ester (POE) oils
are used in Lennox units charged with HFC−410A
refrigerant. Residual mineral oil can act as an
insulator, preventing proper heat transfer. It can also
clog the expansion device, and reduce the system
performance and capacity.
Failure to properly flush the system per the
instructions below will void the warranty.
Leak Test Line Set and Indoor Coil
IMPORTANT
Leak detector must be capable of sensing HFC
refrigerant.
WARNING
When using a high pressure gas such as
dry nitrogen to pressurize a refrigeration
or air conditioning system, use a
regulator that can control the pressure
down to 1 or 2 psig (6.9 to 13.8 kPa).
WARNING
Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.
Failure to follow this warning may result in personal injury
or death.
TO VAPOR
SERVICE VALVE
HFC−410A
MANIFOLD GAUGE SET
OUTDOOR UNIT
HIGHLOW
NITROGEN
AWith both manifold valves closed, connect the cylinder of HFC−410A refrigerant to the center port of the manifold gauge set. Open the valve
on the HFC−410A cylinder (vapor only).
BOpen the high pressure side of the manifold to allow HFC−410A into the line set and indoor unit. Weigh in a trace amount of HFC−410A.[A
trace amount is a maximum of two ounces (57 g) refrigerant or three pounds (31 kPa) pressure]. Close the valve on the HFC−410A cylinder
and the valve on the high pressure side of the manifold gauge set. Disconnect the HFC−410A cylinder.
CConnect a cylinder of dry nitrogen with a pressure regulating valve to the center port of the manifold gauge set.
DAdjust dry nitrogen pressure to 150 psig (1034 kPa). Open the valve on the high side of the manifold gauge set in order to pressurize the line set
and the indoor unit.
EAfter a few minutes, open one of the service valve ports and verify that the refrigerant added to the system earlier is measurable with a leak
detector.
FAfter leak testing disconnect gauges from service ports.
After the line set has been connected to the indoor and outdoor units, check the line set connections and indoor unit for leaks. Use the
following procedure to test for leaks:
AConnect an HFC−410A manifold gauge set high pressure hose to
the vapor valve service port.
NOTE  Normally, the high pressure hose is connected to the
liquid line port. However, connecting it to the vapor port better
protects the manifold gauge set from high pressure damage.
BWith both manifold valves closed, connect the cylinder of
HFC−410A refrigerant to the center port of the manifold gauge set.
NOTE  Later in the procedure, the
HFC−410A container will be replaced
by the nitrogen container.
1CONNECT GAUGE SET
2TEST FOR LEAKS
A
B
Figure 13. Leak Test

Page 19
XP21 SERIES
Evacuating Line Set and Indoor Coil
AOpen both manifold valves and start the vacuum pump.
BEvacuate the line set and indoor unit to an absolute pressure of 23,000 microns (29.01 inches of mercury).
NOTE  During the early stages of evacuation, it is desirable to close the manifold gauge valve at least once. A rapid rise in pressure
indicates a relatively large leak. If this occurs, repeat the leak testing procedure.
NOTE  The term absolute pressure means the total actual pressure within a given volume or system, above the absolute zero of
pressure. Absolute pressure in a vacuum is equal to atmospheric pressure minus vacuum pressure.
CWhen the absolute pressure reaches 23,000 microns (29.01 inches of mercury), perform the following:
SClose manifold gauge valves
SClose valve on vacuum pump
STurn off vacuum pump
SDisconnect manifold gauge center port hose from vacuum pump
SAttach manifold center port hose to a dry nitrogen cylinder with pressure regulator set to 150 psig (1034 kPa) and purge the hose.
SOpen manifold gauge valves to break the vacuum in the line set and indoor unit.
SClose manifold gauge valves.
DShut off the dry nitrogen cylinder and remove the manifold gauge hose from the cylinder. Open the manifold gauge valves to release the
dry nitrogen from the line set and indoor unit.
EReconnect the manifold gauge to the vacuum pump, turn the pump on, and continue to evacuate the line set and indoor unit until the
absolute pressure does not rise above 500 microns (29.9 inches of mercury) within a 20−minute period after shutting off the vacuum pump
and closing the manifold gauge valves.
FWhen the absolute pressure requirement above has been met, disconnect the manifold hose from the vacuum pump and connect it to an
upright cylinder of HFC−410A refrigerant. Open the manifold gauge valve 1 to 2 psig in order to release the vacuum in the line set and
indoor unit.
GPerform the following:
OUTDOOR
UNIT
TO VAPOR
SERVICE VALVE
TO LIQUID LINE
SERVICE VALVE
MICRON
GAUGE
VACUUM PUMP
A34000 1/4 SAE TEE WITH
SWIVEL COUPLER
500
MANIFOLD
GAUGE SET
HFC−410A
RECOMMEND
MINIMUM 3/8" HOSE
AConnect low side of manifold gauge set
with 1/4 SAE in−line tee to vapor line
service valve
BConnect high side of manifold gauge
set to liquid line service valve
CConnect micron gauge available
connector on the 1/4 SAE in−line tee.
DConnect the vacuum pump (with
vacuum gauge) to the center port of the
manifold gauge set. The center port
line will be used later for both the
HFC−410A and nitrogen containers.
HIGH
LOW
1
2
3
4
5
6
7
8
9
10
11 12
1/6 TURN
NITROGEN
1CONNECT GAUGE SET
A
B
C
D
2EVACUATE THE SYSTEM
NOTE  Remove cores from service valves (if not already done).
SClose manifold gauge valves.
SShut off HFC−410A cylinder.
SReinstall service valve cores by removing manifold hose from service valve. Quickly install cores with core
tool while maintaining a positive system pressure.
SReplace stem caps and secure finger tight, then tighten an additional one−sixth (1/6) of a turn as illustrated.
Figure 14. Evacuating System

Page 20
506601−01
IMPORTANT
Use a thermocouple or thermistor electronic vacuum
gauge that is calibrated in microns. Use an instrument
capable of accurately measuring down to 50 microns.
WARNING
Danger of Equipment Damage. Avoid deep vacuum
operation. Do not use compressors to evacuate a
system. Extremely low vacuums can cause internal
arcing and compressor failure. Damage caused by
deep vacuum operation will void warranty.
Evacuating the system of non−condensables is critical for
proper operation of the unit. Non−condensables are
defined as any gas that will not condense under
temperatures and pressures present during operation of
an air conditioning system. Non−condensables and water
suction combine with refrigerant to produce substances
that corrode copper piping and compressor parts.
Electrical
In the U.S.A., wiring must conform with current local codes
and the current National Electric Code (NEC). In Canada,
wiring must conform with current local codes and the current
Canadian Electrical Code (CEC).
Refer to the furnace or air handler installation instructions
for additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.
24VAC TRANSFORMER
Use the transformer provided with the furnace or air
handler for low-voltage control power (24VAC − 40 VA
minimum)
Refer to the unit nameplate for minimum circuit ampacity, and
maximum fuse or circuit breaker (HACR per NEC). Install power
wiring and properly sized disconnect switch.
NOTE  Units are approved for use only with copper conductors.
Ground unit at disconnect switch or to an earth ground.
SIZE CIRCUIT AND INSTALL DISCONNECT
SWITCH
1
NOTE  24VAC, Class II circuit connections are made in the control
box.
Install room thermostat (ordered separately) on an inside wall
approximately in the center of the conditioned area and 5 feet
(1.5m) from the floor. It should not be installed on an outside wall
or where it can be affected by sunlight or drafts.
THERMOSTAT
5 FEET
(1.5M)
INSTALL THERMOSTAT
2
SERVICE
DISCONNECT
SWITCH
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.
CAUTION
ELECTROSTATIC DISCHARGE
(ESD)
Precautions and Procedures
Electrostatic discharge can affect electronic components. Take precautions
during unit installation and service to protect the unit’s electronic controls.
Precautions will help to avoid control exposure to electrostatic discharge by
putting the unit, the control and the technician at the same electrostatic potential.
Neutralize electrostatic charge by touching hand and all tools on an unpainted unit
surface before performing any service procedure