Lennox XPG20 User manual

06/09 506238−01
*2P0609* *P506238-01*
Page 1
E2009 Lennox Industries Inc.
Dallas, Texas, USA
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
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.
IMPORTANT
This unit must be matched with an indoor coil as
specified in Lennox’ Engineering Handbook.
Coils previously charged with HCFC−22 must be
flushed.
INSTALLATION
INSTRUCTIONS
Dave Lennox Signature®
Collection XPG20
SunSourcetComfort
System
SOLAR ASSIST HEAT PUMPS
506238−01
06/09
Supersedes 05/09
Table of Contents
Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Field Supplied Components 2. . . . . . . . . . . . . . . . . . . . .
Unit Parts Arrangement 3. . . . . . . . . . . . . . . . . . . . . . . .
Control Panel Parts Arrangement 3. . . . . . . . . . . . . . . .
Shipping and Packing List 4. . . . . . . . . . . . . . . . . . . . . .
System Overview 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Gauge Set 4. . . . . . . . . . . . . . . . . . . . . . . . . .
Recovering Refrigerant from Existing System 6. . . . .
Removing Existing Outdoor Unit 6. . . . . . . . . . . . . . . . .
Positioning New Outdoor Unit 7. . . . . . . . . . . . . . . . . . .
Removing and Installing Panels 8. . . . . . . . . . . . . . . . .
New or Replacement Line Set 9. . . . . . . . . . . . . . . . . . .
Brazing Connections 11. . . . . . . . . . . . . . . . . . . . . . . . . . .
Flushing the System 13. . . . . . . . . . . . . . . . . . . . . . . . . . .
Leak Testing the System 15. . . . . . . . . . . . . . . . . . . . . . .
Evacuating the System 17. . . . . . . . . . . . . . . . . . . . . . . . .
Servicing Unit Delivered Void of Charge 18. . . . . . . . . .
Electrical 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Solar Module Setup and Connections 20. . . . . . . . . . . .
Unit Start−Up 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Testing Charge 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding or Removing Refrigerant 26. . . . . . . . . . . . . . . .
System Operations 29. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lennox System Operation Monitor (LSOM) 29. . . . . . .
LSOM Module and System Troubleshooting LEDs 30.
Defrost System 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Defrost Control Board Diagnostic LEDs 39. . . . . . . . . . .
Maintenance 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Homeowner Information 40. . . . . . . . . . . . . . . . . . . . . . . .
Field Operational Checklist 42. . . . . . . . . . . . . . . . . . . . .
Start−Up and Performance Checklist 43. . . . . . . . . . . . .
Litho U.S.A.

Page 2
506238−01 06/09
Unit Dimensions −− Inches (mm)
39−1/2
(1003)
1 (25)
LIQUID
LINE
INLET
SIDE VIEW ACCESS VIEW
DISCHARGE AIR
4−5/8
(117)
BASE
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)
SOLAR
MODULE
WIRING
ELECTRICAL INLET
(CONTROL WIRING
− LOW VOLTAGE)
Field Supplied Components
The followings items are field supplied (not included).
Parts Lennox Catalog Numbers
Solar Module (see Figure 17 for specifications) 48W00
Solar Module Mounting Kit − Roof applications 48W01
Solar Module Mounting Kit − Pole applications 48W02
DC rated disconnect (15A)
48W03
DC ground fault (if required)
DC surge arrestor
MC4 Cable 12 Gauge., 10 foot single wire (module leads to junction box) 48W04

Page 3
XPG20 SERIES
Unit Parts Arrangement
CONTACTOR
DEFROST
CONTROL
VAPOR VALVE AND GAUGE PORT
TWO−STAGE COMPRESSOR
OUTDOOR FAN
SOLAR ASSIST DC MOTOR
LENNOX SYSTEM OPERATION
MONITOR (LSOM)
RUN CAPACITOR
DISCHARGE LINE
REVERSING VALVE
SOLAR PANEL
TERMINAL BLOCK
BI−FLOW FILTER DRIER
FAN MOTOR
SOLAR ASSIST DC MOTOR
COUPLER
HIGH PRESSURE SWITCH
LOW PRESSURE
SWITCH
COMPRESSOR TERMINAL
PLUG
FAN MOTOR MOUNT
Control Panel Parts Arrangement
GROUND LUG
HIGH VOLTAGE FIELD
CONNECTIONS
CONTACTOR−1POLE,25A
(K1−1)
DEFROST CONTROL BOARD
(A108)
LOW VOLTAGE − CONTROL WIRE TIE
LSOM MODULE (A132) TERMINAL BLOCK − TWO POSITION
(SOLAR)
CAPACITOR
(C12)
DEFROST RELAY SOLAR FAN
(K227)
SOLAR FAN RELAY (24VAC) (K228)

Page 4
506238−01 06/09
WARNING
This product and/or the indoor unit it is matched
with may contain fiberglass wool.
Disturbing the insulation during installation,
maintenance, or repair will expose you to fiberglass
wool dust. Breathing this may cause lung cancer.
(Fiberglass wool is known to the State of California
to cause cancer.)
Fiberglass wool may also cause respiratory, skin,
and eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact
your supervisor.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379−9900
Shipping and Packing List
Check unit for shipping damage. Consult last carrier
immediately if damage is found.
1  Assembled outdoor unit.
1  Bag assembly that consist of the following:
1  Bushing (for low voltage wiring)
2  Isolation grommets for liquid and suction lines
System Overview
The SunSourcetComfort System heat pump, which will
also be referred to in this instruction as the outdoor unit,
uses HFC−410A refrigerant. This outdoor unit must be
installed with a matching indoor unit and line set as outlined
in the Lennox XPG20 Engineering Handbook.
This outdoor unit is designed for use in systems that use
check thermal expansion valve (CTXV) refrigerant
metering device.
Operating Gauge Set
This instruction is intended as a general guide and do not
supersede local codes in any way. Consult authorities who
have jurisdiction before installation.
TORQUE REQUIREMENTS
When servicing or repairing HVAC components, ensure
the fasteners are appropriately tightened. Table 1 list
torque values for fasteners.
IMPORTANT
To prevent stripping of the various caps used, the
appropriately sized wrench should be used and
fitted snugly over the cap before tightening.
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.
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
Coupler Set Screws 150 in.− lb. 17 NM
Torque Arm Nut 55 in.− lb 6 NM
Assist Motor Bolts 35 in.− lb. 4 NM
Motor Mount Wire
Bracket
55 in.− lb 6 NM

12
3
4
5
6
7
8
9
10
11 12
1/6 TURN
1/12 TURN
12
3
4
5
6
7
8
9
10
11 12
Page 5
XPG20 SERIES
USING MANIFOLD GAUGE SET
When checking the system charge, use only a manifold
gauge set that features low−loss and anti−blow back
fittings.
(VALVE STEM
SHOWN CLOSED)
INSERT HEX
WRENCH HERE
VALVE STEM
FRONT-SEATED
TO OUTDOOR
UNIT
SERVICE PORT
CORE
TO INDOOR
UNIT
SERVICE PORT
SERVICE PORT
CAP
CLOSED TO BOTH
INDOOR AND OUTDOOR
UNITS
STEM CAP
ANGLE−TYPE SERVICE VALVE
(FRONT−SEATED CLOSED)
SERVICE PORT
SERVICE PORT
CORE
TO OUTDOOR
UNIT
STEM CAP
(VALVE STEM
SHOWN OPEN)
INSERT HEX
WRENCH HERE
SERVICE PORT
CAP
TO INDOOR
UNIT
OPEN TO BOTH
INDOOR AND
OUTDOOR
UNITS
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
OPEN TO LINE SET WHEN
VALVE IS CLOSED, TO BOTH
LINE SET AND UNIT WHEN
VALVE IS OPEN.
BALL−TYPE SERVICE
VALVE
Figure 1. Various Types of Service Valves
Manifold gauge set used with HFC−410A refrigerant
systems must be capable of handling the 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 up to 800
psig of pressure with a 4000 psig burst rating.
OPERATING SERVICE VALVES
The liquid and vapor line service valves are used for
removing refrigerant, flushing, leak testing, evacuating,
checking charge and charging.
Each valve is equipped with a service port which has a
factory−installed valve stem as illustrated in Figure 1.
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 to the service port.
3. When testing is completed, replace service port cap and
tighten as follows:
DWith Torque Finger Wrench:
tighten and then tighten per
Table 1.
DWithout Torque Wrench:
Finger tighten and use an
appropriately sized wrench to
turn an additional 1/6 turn.
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.
STo open valve, roate stem counterclockwise 90°.
STo close rotate stem clockwise 90°.
Reinstall Stem Cap:
Replace the stem cap and tighten as follows:
SWith Torque Wrench: Finger
tighten and then tighten per Table 1.
SWithout Torque Wrench: Finger
tighten and use an appropriately
sized wrench to turn an
additional 1/12 turn clockwise.
NOTE Later in the procedure, the HFC−410A container
will be replace by the nitrogen container. A label with
specific torque requirements may be affixed to the stem
cap. If the label is present, use the specified torque.

Page 6
506238−01 06/09
Recovering Refrigerant from Existing
System
Connect gauge set as illustrated in Figure 2 for removing
refrigerant.
MANIFOLD GAUGES
RECOVERY
MACHINE
CLEAN
RECOVERY
CYLINDER
OUTDOOR
UNIT
HIGH
LOW
CONNECT TO THE EXISTING UNIT A GAUGE SET, CLEAN RECOVERY
CYLINDER AND A RECOVERY MACHINE. USE THE INSTRUCTIONS
PROVIDED WITH THE RECOVERY MACHINE ON HOW TO SETUP THE
CONNECTIONS.
Figure 2. Setup Gauge Set
REMOVING REFRIGERANT
Remove existing HCFC−22 refrigerant using one of the
following procedures:
METHOD 1:
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 plan on using new
HCFC−22 refrigerant to flush the system.
IMPORTANT
Some system configurations may contain higher
than normal refrigerant charge due to either large
internal coil volumes, and/or long line set. The
following conditions may cause the compressor to
stop functioning:
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 cycled 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.
Once the compressor can not pump down to a lower
pressure due to one of the above system conditions, shut
off the suction 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:
1. Start the existing HCFC−22 system in the cooling
mode and close the liquid line valve.
2. Pump as much of the existing HCFC−22 refrigerant
with the compressor back into the outdoor unit until
you have reached the limitations of the outdoor
system. Turn the outdoor unit main power OFF and
use a recovery machine to remove the remaining
refrigerant in the system.
NOTE  It may be necessary to bypass the low pressure
switches if equipped to ensure complete refrigerant
evacuation.
3. When the low side system pressures reach 0 psig,
close the suction line valve.
4. Check gauges after shutdown to confirm that the
valves are not allowing refrigerant to flow back into the
low side of the system.
Removing Existing Outdoor Unit
Perform the following task at the existing outdoor unit:
SDisconnect line set at the service valves.
SDisconnect electrical service at the disconnect switch
as illustrated in Figure 3.
SRemove old outdoor unit.
SERVICE
DISCONNECT
SWITCH
MAIN FUSE
BOX/BREAKER
PANEL
Disconnect all power to the existing outdoor unit at the disconnect
switch or main fuse box/breaker panel.
Figure 3. Disconnect Power

Page 7
XPG20 SERIES
Positioning New Outdoor Unit
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.
SEE NOTES BELOW THIS FIGURE FOR FURTHER DETAILS.
CONTROL PANEL
ACCESS LOCATION
Figure 4. Installation Clearances
NOTES:
SService clearance of 30 in. (762 mm) must be
maintained on one of the sides adjacent to the control
panel.
SClearance to one of the other three sides must be 36
in. (914 mm).
SClearance to one of the remaining two sides may be
12 in. (305 mm) and the final side may be 6 in. (152
mm).
S48 in. (1219 mm) clearance required on top of unit.
SA clearance of 24 in. (610 mm) must be maintained
between two units.
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, 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.
SIn locating and positioning the unit, take into
consideration where the solar module will be located
and/or how the wire can or will be routed to it.
INSTALL UNIT AWAY FROM
WINDOWS
TWO 90° ELBOWS INSTALLED IN
LINE SET WILL REDUCE LINE SET
VIBRATION.
Figure 5. Outside Unit Placement
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 6.
NOTE  If necessary for stability, anchor unit to slab as
described in Stabilizing Unit on Uneven Surfaces on page 9.
INSTALL UNIT LEVEL OR, IF ON A SLOPE, MAINTAIN SLOPE
TOLERANCE OF 2 DEGREES (OR 2 INCHES PER 5 FEET [50 MM
PER 1.5 M]) AWAY FROM BUILDING STRUCTURE.
MOUNTING
SLAB
BUILDING
STRUCTURE
GROUND LEVEL
Figure 6. Slab Mounting at Ground Level

Page 8
506238−01 06/09
ELEVATING THE UNIT
These units are outfitted with elongated support feet as
illustrated in Figure 7.
LEG DETAIL
BASE
2" (50.8MM) SCH
40 FEMALE
THREADED
ADAPTER
Figure 7. Elevated Slab Mounting using Feet
Extenders
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" SCH 40 female threaded adapter.
The specified coupling will fit snuggly into the recessed
portion of the feet. Use additional 2" SCH 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.
Removing and Installing Panels
CAUTION
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.
WARNING
Unit must be grounded in accordance
with national and local codes.
Electric Shock Hazard. Can cause
injury or death.
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.
ACCESS PANEL
Removal and reinstallation of the access panel is
illustrated in Figure 8.
REMOVE 4 SCREWS TO REMOVE
PANEL FOR ACCESSING
COMPRESSOR AND CONTROL.
POSITION PANEL WITH HOLES
ALIGNED; INSTALL SCREWS AND
TIGHTEN.
Figure 8. Access Panel
LOUVERED PANELS
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 Figure 9, Detail B.
3. Move panel down until lip of upper tab clears the top
slot in corner post as illustrated in Figure 9, Detail A.
Position and Install PanelPosition the panel almost
parallel with the unit as illustrated in Figure 9, Detail D with
the screw side as close to the unit as possible. Then, in a
continuous motion:
SSlightly rotate and guide the lip of top tab inward as
illustrated in Figure 9, Details A and C; then upward
into the top slot of the hinge corner post.
SRotate panel to vertical to fully engage all tabs.
SHolding the panel’s hinged side firmly in place, close
the right−hand side of the panel, aligning the screw
holes.

Page 9
XPG20 SERIES
Detail A
Detail C
Detail B
ROTATE IN THIS DIRECTION; THEN
DOWN TO REMOVE PANEL
SCREW
HOLES
LI
P
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
IMPORTANT! Do not allow panels to hang on unit by top tab. Tab is
for alignment and not designed to support weight of panel.
Figure 9. Removing/Installing Louvered Panels
When panel is correctly positioned and aligned, insert the
screws and tighten.
STABILIZING UNIT ON UNEVEN SURFACES
With unit positioned at installation site, remove two side
louvered panels to expose the unit base pan. Install the
brackets as illustrated in Figure 10 using conventional
practices. Replace the panels after installation is
complete.
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.
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.
ONE BRACKET PER SIDE (MIN.); FOR EXTRA STABILITY, TWO
BRACKETS PER SIDE, 2" FROM EACH CORNER.
CONCRETE SLAB − USE PLASTIC
PLASTIC ANCHOR (HOLE DRILL
1/4")PLASTIC SLAB − NO PLASTIC
ANCHOR (HOLE DRILL 1/8")
COIL
BASE PAN
CORNER
POST
STABILIZING
BRACKET (18
GAUGE METAL − 2"
WIDTH; HEIGHT AS
REQ’D)
Slab Side Mounting
#10 1/2" LONG
SELF−DRILLING
SHEET METAL
SCREWS
#10 1−1/4" LONG
HEX HD SCREW
AND FLATWASHER
MINIMUM 1
PER SIDE
STABILIZING BRACKET (18
GAUGE METAL − 2" WIDTH;
HEIGHT AS REQ’D); BEND
TO FORM RIGHT ANGLE
FOR EXTRA
STABILITY
Deck Top Mounting
Figure 10. Installing Stabilizer Brackets
New or Replacement Line Set
This section provides information on installation or
replacement of existing line set. If line set are not being
installed then proceed to Brazing Connections on page 11.
If refrigerant lines are routed through a wall, 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. Also, consider the following when
placing and installing a high−efficiency air conditioner.

Page 10
506238−01 06/09
REFRIGERANT LINE SET
Field refrigerant piping consists of liquid and suction lines
from the outdoor unit (braze connections) to the indoor unit
coil (flare or sweat connections). Use Lennox L15 (sweat,
non−flare) series line set, or use field−fabricated refrigerant
lines as listed in Table 2.
Table 2. Refrigerant Line Set
Model
Field Connections Recommended Line Set
Liquid
Line
Suction
Line
Liquid
Line
Suction
Line L15 Line Set
−036 3/8".
(10 mm)
7/8"
(22 mm)
3/8"
(10 mm)
7/8"
(22 mm)
L15−65
15 ft. − 50 ft.
(4.6 m − 15 m)
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 points:
SModel (XPG20) 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 and vertical rise or drop in the
piping.
MATCHING WITH NEW OR EXISTING INDOOR COIL
AND LINE SET
The RFC1  metering line consisted of a small bore
copper line that runs from condenser to evaporator coil.
Refrigerant is metered into the evaporator by utilizing
temperature/pressure evaporation effects on refrigerant in
the small RFC line. The length and bore of the RFC line
corresponded to the size of cooling unit.
Existing line set of proper size may be reused. If system
was previously HCFC−22 then lines must be flushed (see
Flushing the System on page ). If a Lennox RFC1 liquid line
is existing, it must be replaced.
If the XPG20 must be matched with a proper coil. The only
existing installed coils that could be re−used would be
current coils listed in the XPG20 matchup charts.
INSTALLING LINE SET
Line Set Isolation  This reference illustrates
procedures, which ensure proper refrigerant line set
isolation:
SInstallation of a transition from vertical to
horizontal is illustrated in Figure 11.
SInstallation of line set on vertical runs is illustrated in
Figure 12.
SInstallation of line set on horizontal runs is
illustrated in Figure 13.
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
SUCTION LINE
WRAPPED WITH
ARMAFLEX
LIQUID LINE
IMPORTANT! Refrigerant lines
must not contact structure.
OUTSIDE WALL LIQUID LINE
SUCTION LINE
IMPORTANT - Refriger-
ant lines must not contact
wall.
WOOD BLOCK
BETWEEN STUDS
STRAP
SLEEVE
WOOD BLOCK
STRAP
SLEEVE
WIRE TIE
WIRE TIE
WIRE TIE
INSIDE WALL
Figure 11. Refrigerant Line Set: Transition from
Vertical to Horizontal
ANCHORED HEAVY NYLON
WIRE TIE OR AUTOMOTIVE
MUFFLER-TYPE HANGER
STRAP LIQUID
LINE TO SUCTION
LINE
WALL
STUD
LIQUID LINE
METAL SLEEVE
SUCTION LINE − WRAPPED
IN ARMAFLEX
AUTOMOTIVE
MUFFLER-TYPE HANGER
Figure 12. Refrigerant Line Set: Installing Vertical
Runs (New Construction Shown)