Lennox XC15 Series User manual

01/06 505,095M
*2P0106* *P505095M*
Page 1
E2006 Lennox Industries Inc.
Dallas, Texas, USA
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
WARNING
Improper installation, adjustment, alteration, ser-
vice or maintenance can cause property damage,
personal injury or loss of life. Installation and ser-
vice must be performed by a qualified installer or
service agency.
IMPORTANT
This unit must be matched with an indoor coil as
specified in Lennox’ Engineering Handbook.
Coils previously charged with R−22 must be flu-
shed.
XC15 Outdoor Unit
XC15 outdoor units use R−410A refrigerant. This unit must
be installed with a matching indoor coil and line set as out-
lined in the Lennox Engineering Handbook. XC15 outdoor
units are designed for use in expansion valve (TXV) sys-
tems only. Refer to the Lennox Engineering Handbook for
expansion valve kits which must be ordered separately.
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.
Shipping and Packing List
1 − Assembled XC15 outdoor unit
1 − Bushing (for low voltage wiring)
2 − Grommets (for liquid and vapor lines)
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
INSTALLATION
INSTRUCTIONS
XC15 Series Units
CONDENSING UNITS
505,095M
01/06
Table of Contents
XC15 Outdoor Unit 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shipping And Packing List 1. . . . . . . . . . . . . . . . . . . . . . . .
Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Information 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting Unit 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removing Panels 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Refrigerant Piping 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flushing Existing Line Set and Indoor Coil 9. . . . . . . . . .
Refrigerant Metering Device 10. . . . . . . . . . . . . . . . . . . . .
Manifold Gauge Set 11. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Valves 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Leak Testing 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Evacuation 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Start−up 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Refrigerant Charging 13. . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Operation 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional Accessories 18. . . . . . . . . . . . . . . . . . . . . . . . . . .
XC15 Start−Up and Performance Check List 19. . . . . . . .
Homeowner’s Information − Maintenance 19. . . . . . . . . .
Thermostat Operation 20. . . . . . . . . . . . . . . . . . . . . . . . . . .
Sound Reduction Cover & Assembly Procedure 20. . . .
General Information
When servicing or repairing HVAC components, ensure
the fasteners are appropriately tightened. Table 1 shows
torque values for fasteners, and for port and valve caps.
Table 1
Torque Requirements
Part Recommended Torque
Service valve cap 8 ft.− lb. 11 NM
Sheet metal screws 16 in.− lb. 2 NM
Machine screws #8 16 in.− lb. 2 NM
Compressor bolts 90 in.− lb. 10 NM
Gauge port seal cap 8 ft.− lb. 11 NM
These instructions are intended as a general guide and do
not supersede national or local codes in any way. Consult
authorities having jurisdiction before installation.
Litho U.S.A.

Page 2
505095M 1/3/06
Unit Dimensions − inches (mm) and Parts Arrangement
39−1/2
(1003) 35−1/2
(902)
18−5/8
(473)
8 (203)
1 (25)
4−7/16
(113)
LIQUID
LINE
INLET
SUCTION
LINE
INLET
ELECTRICAL
INLETS
TOP VIEW
SIDE VIEW ACCESS VIEW
DISCHARGE AIR
CONTACTOR
SYSTEM OPERA-
TION MONITOR
RUN CAPACITOR
DISCHARGE LINE
VAPOR VALVE AND
GAUGE PORT
VAPOR LINE
LOW PRESSURE
SWITCH
FILTER DRIER
OUTDOOR FAN
COMPRESSOR
AND SOUND
REDUCTION
COVER (SEE
PAGE 20 FOR
COVER
INFORMATION)
COMPRESSOR
TERMINAL
PLUG
HIGH
PRESSURE
SWITCH
Figure 1
37 (940)
[−024 thru −042]
47 (1194)
[−048 and −060]
21−1/8 (537)
[−024 thru −042]
31−1/8 (791)
[−048 and −060]
10−3/8 (264)
10−1/2
(267)
13−1/2
(343)
9−1/4
(234)
18
(457)
Setting the Unit
CAUTION
In order to avoid injury, take proper precaution when
lifting heavy objects.
Refer to unit dimensions for sizing mounting slab, plat-
forms or supports. Refer to figure 2 for installation clear-
ances.
Service Panel Clearance
A service clearance of 30" (762 mm) must be maintained
on the access panel side of the unit (see figure 2).

Page 3
XC15 SERIES
*A service clearance of 30" (762 mm) must be maintained on
the access panel side of the unit. Clearance to one of the oth-
er three sides must be 36" (914 mm). Clearance to one of the
remaining two sides may be 12" (304 mm) and the final side
may be 6" (152 mm).
A clearance of 24" (610 mm) must be maintained between
two units. 48" (1219 mm) clearance required on top of unit.
Maximum soffit overhang is 36" (914 mm).
Installation Clearances
Figure 2
(as
noted)
30 in. (762−mm)
(as noted)
(as
noted)
Slab Mounting
When installing a unit at grade level, the top of the slab
should be high enough above the grade so that water from
higher ground would not collect around the unit. See figure
3. Slab may be level or have a slope tolerance away from
the building of not more than 2 degrees or 2 inches per 5
feet (51 mm per 1524 mm).
INSTALL UNIT LEVEL OR, IF ON A SLOPE, MAINTAIN SLOPE TOLERANCE OF 2
DEGREES (OR 2 INCHES PER 5 FEET [51 MM PER 1.5 M]) AWAY FROM
BUILDING STRUCTURE.
Slab Mounting At Ground Level
MOUNTING
SLAB
BUILDING
STRUCTURE
Figure 3
Roof Mounting
Install unit at a minimum of 4 inches above the surface of
the roof. Care must be taken to ensure weight of unit is
properly distributed over roof joists and rafters. Either red-
wood or steel supports are recommended.
Removing Panels
WARNING
This product and/or the indoor unit it is matched
with may contain fiberglass wool.
Disturbing the insulation during installation, main-
tenance, or repair will expose you to fiberglass wool
dust. Breathing this may cause lung cancer. (Fiber-
glass 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
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 dam-
age to objects or structures nearby, nor will the pan-
els 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 bat-
tered.
Access Panel
WARNING
Unit must be grounded in accordance
with national and local codes. Elec-
tric Shock Hazard. Can cause injury
or death.
Line voltage is present at all compo-
nents when unit is not in operation on
units with single-pole contactors. Dis-
connect all remote electric power sup-
plies before opening access panel.
Unit may have multiple power sup-
plies.

Page 4
505095M 1/3/06
Remove and reinstall the access panel as described in fig-
ure 4.
Remove 4 screws to
remove panel for
accessing compressor
and controls.
Install by positioning
panel with holes
aligned; install screws
and tighten.
Figure 4
Access Panel
Louvered Panels
CAUTION
Physical contact with metal edges and corners can
result in personal injury. Be aware of, and use cau-
tion when working with panels.
Remove the louvered panels as follows:
1. Remove 2 screws, allowing the panel to swing open
slightly.
2. Hold the panel firmly throughout this procedure.
Rotate bottom corner of panel away from hinge corner
post until lower 3 tabs clear the slots (see figure 5, De-
tail B).
3. Move panel down until lip of upper tab clears the top
slot in corner post (see figure 5, Detail A).
Position and Install PanelPosition the panel almost
parallel with the unit (figure 5, 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 (fig-
ure 5, 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.
When panel is correctly positioned and aligned, insert the
screws and tighten.
Detail A
Detail C
Detail B
Figure 5
Removing/Installing Louvered Panels
MAINTAIN MINIMUM PANEL ANGLE (AS CLOSE TO PARALLEL WITH THE UNIT
AS POSSIBLE) WHILE INSTALLING PANEL.
PREFERRED ANGLE
FOR INSTALLATION
Detail D
ROTATE IN THIS DIRECTION;
THEN DOWN TO REMOVE PANEL
SCREW
HOLES
ANGLE MAY BE TOO
EXTREME
HOLD DOOR FIRMLY TO THE HINGED
SIDE TO MAINTAIN
FULLY−ENGAGED TABS
LIP
IMPORTANT! Do not allow panels to hang on unit by top tab. Tab
is for alignment and not designed to support weight of panel.
Panel shown slightly ro-
tated to allow top tab to
exit (or enter) top slot for
removing (or installing)
panel.
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).

Page 5
XC15 SERIES
Refer to the furnace or blower coil installation instructions
for additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.
1. Install line voltage power supply to unit from a properly
sized disconnect switch. See figure 6.
Figure 6
Typical Field Wiring Diagram
WARNING! − ELECTRIC SHOCK HAZARD. Can cause INJURY
or DEATH. Unit must be grounded in accordance with national
and local codes.
NOTE − For use with copper conductors only. Refer to unit rating
plate for minimum circuit ampacity and maximum over-current
protection size.
208−230/60/1
GND
L1
L2
READ
WARNING AND
NOTE
2. Ground unit at unit disconnect switch or to earth
ground.
3. Connect conduit to the unit via the bottom hole using
a proper conduit fitting.
NOTE −Units are approved for use only with copper
conductors. 24V, Class II circuit connections are
made in the low voltage junction box. Refer to figure 7
for field wiring diagram. A complete unit wiring dia-
gram is located on the back side of the access panel.
NOTE − For proper voltages, select thermostat wire
gauge per the following chart:
Wire run length AWG # Insulation type
less than 100’ (30m) 18 color−coded, temperature
º
more than 100’ (30m) 16
color coded,
temperature
rating 35ºC minimum
4. Install room thermostat (ordered separately) on an in-
side wall approximately in the center of the conditioned
area and 5 feet (1.5 m) from the floor. It should not be
installed on an outside wall or where it can be affected
by sunlight, drafts or vibrations.
5. Install low voltage wiring from outdoor to indoor unit
and from thermostat to indoor unit. See figure 7.
6. LSOM L Terminal WiringConnect L terminal of the
room thermostat to the L (Brown) field wire connec-
tion.
7. LSOM Installation VerificationVerification proce-
dures are described in System Operation under Sys-
tem Operation Monitor (see Page 16).
NOTE − Wiring the module incorrectly will cause false
LED codes. Table 8 (see page 17) describes LED op-
eration when the module is incorrectly wired and the
action required to correct the problem.
Figure 7
Typical Wiring Diagram

Page 6
505095M 1/3/06
Refrigerant Piping
If the XC15 unit is being installed with an indoor coil and line
set, make the refrigerant connections as outlined in this
section. f an existing line set and/or indoor coil is going to
be used to complete the XC15 system, refer to this section,
as well as the flushing section which follows.
Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit (sweat connections) to the indoor coil
(flare or sweat connections). Use Lennox L15 (sweat, non−
flare) series line sets as shown in table 2 or use field−fabri-
cated refrigerant lines. Valve sizes are also listed in table 2.
Table 2
Refrigerant Line Sets
Valve Sizes Recommended Line Set
Model
Liquid
Line
Vapor
Line
Liquid
Line
Vapor
Line
L15
Line Sets
−024
−030
−036
3/8 in.
(10 mm)
3/4 in.
(19 mm)
3/8 in
(10 mm)
3/4 in.
(19 mm)
L15−41
15 − 50 ft.
(5 − 15 m)
−042
−048
3/8 in.
(10 mm)
7/8 in
(22 mm)
3/8 in.
(10 mm)
7/8in
(22 mm)
L15−65
15 − 50 ft.
(5 − 15m)
−060 3/8 in.
(10 mm)
1−1/8 in.
(29 mm)
3/8 in.
(10 mm)
1−1/8 in.
(29 mm)
Field
Fabricated
NOTE − When installing refrigerant lines longer than 50
feet, contact Lennox Technical Support Product
Applications for assistance. To obtain the correct
information from Lennox, be sure to communicate the
following points:
SLine set diameters for the unit being installed (from
table 2)
SModel (XC15) and size of unit (e.g. −060).
IMPORTANT
Matching XC15 with new Indoor Coil and Line
SetIf an existing indoor coil equipped with an
RFCI metering device is being replaced, also install
a new liquid line prior to installing the XC15 unit.
Installing Refrigerant Line
If refrigerant lines are routed through a wall, seal and iso-
late the opening so vibration is not transmitted to the build-
ing. Pay close attention to line set isolation during installa-
tion of any HVAC system. When properly isolated from
building structures (walls, ceilings. floors), the refrigerant
lines will not create unnecessary vibration and subsequent
noises. Also, consider the following when placing and
installing a high−efficiency outdoor unit:
1. PlacementSome localities are adopting sound ordi-
nances based on the unit’s noise level registered from
the adjacent property, not from the installation proper-
ty. Install the unit as far as possible from the property
line. When possible, do not install the unit directly out-
side a window. Glass has a very high level of sound
transmission (see figure 8).
Install unit
away from
windows
Two 90° elbows installed in line
set will reduce line set vibration.
Figure 8
Outside Unit Placement and Installation
2. Line Set IsolationThe following illustrations dem-
onstrate procedures which ensure proper refrigerant
line set isolation. Figure 10 shows how to install line
sets on horizontal runs. Figure 11 shows how to make
a transition from horizontal to vertical. Figure 12 shows
how to install line sets on vertical runs.
Installing Isolation Grommets
Locate the isolation grommets (provided). Slide grommets
onto vapor and liquid lines. Insert grommets into mullion to
isolate refrigerant lines from sheet metal edges.
WARNING
Polyol ester (POE) oils used with R−410A refriger-
ant absorb moisture very quickly. It is very impor-
tant 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.

Page 7
XC15 SERIES
Brazing Connection Procedure
Before brazing, remove the access panel (see figure 4);
then remove the narrow piping panel to prevent burning off
the paint (see figure 9).
Remove 2
screws and re-
move panel
before brazing.
Figure 9
Piping Panel Removal
PIPING
PANEL
Line set
connection
points.
1. Cut ends of the refrigerant lines square (free from
nicks or dents). Debur the ends. The pipe must remain
round, do not pinch end of the line.
2. When making line set connections, use 1 to 2 psig dry
nitrogen to purge the refrigerant piping. This will help
to prevent oxidation and the introduction of moisture
into the system.
3. Use silver alloy brazing rods (5 or 6 percent minimum
silver alloy for copper−to−copper brazing or 45 percent
silver alloy for copper−to−brass or copper−to−steel
brazing) which are rated for use with R−410A refriger-
ant. While brazing-in the line set connections, wrap a
wet cloth around the valve body and the copper tube
stubs.
4. Quench the joints with a wet cloth to prevent possible
heat damage to the valve core and opening port.
NOTE − The tube end must stay bottomed in the fitting
during final assembly to ensure proper seating, seal-
ing and rigidity.
5. Install the thermal expansion valve in the liquid line at
the indoor coil.
NOTE − Expansion valve (not provided; obtain sepa-
rately) must be approved for use with R−410A refriger-
ant.
Refrigerant Line Sets: Installing Horizontal Runs
METAL
SLEEVE
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.
Figure 10
8 feet
8 feet
Strap the vapor line to the joist or rafter
at 8 ft. intervals then strap the liquid line
to the vapor line.
FLOOR JOIST OR ROOF RAFTER

Page 8
505095M 1/3/06
Refrigerant Line Sets: Transition From Vertical To Horizontal
Strap Liquid Line
To Vapor Line
METAL
SLEEVE
ANCHORED
HEAVY NYLON
WIRE TIE
AUTOMOTIVE
MUFFLER-TYPE
HANGER
WALL
STUD
Figure 11
VAPOR LINE − WRAPPED
IN ARMAFLEX
Strap Liquid
Line To Va-
por Line
WALL
STUD
LIQUID
LINE
METAL
SLEEVE
VAPOR LINE − WRAPPED
IN ARMAFLEX
LIQUID
LINE
Refrigerant Line Sets: Installing Vertical Runs (new construction shown)
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
IMPORTANT!
Refrigerant
lines must
not contact
structure.
OUTSIDE WALL LIQUID LINEVAPOR LINE
IMPORTANT - Refrigerant
lines must not contact wall.
WOOD BLOCK
BETWEEN STUDS
STRAP
SLEEVE
WOOD BLOCK
STRAP
SLEEVE
WIRE TIE
WIRE TIE
WIRE TIE
Figure 12
INSIDE WALL

Page 9
XC15 SERIES
Flushing Existing Line Set & Indoor Coil
WARNING
Danger of fire. Bleeding the refriger-
ant charge from only the high side
may result in the low side shell and
suction tubing being pressurized. Ap-
plication of a brazing torch while
pressurized may result in ignition of
the refrigerant and oil mixture − check
the high and low pressures before un-
brazing.
CAUTION
This procedure should not be performed on sys-
tems which contain contaminants (Example: com-
pressor burn out).
IMPORTANT
If this unit is being matched with an approved line
set or indoor 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 instal-
lation. Take care to empty all existing traps. Polyol
ester (POE) oils are used in Lennox units charged
with R−410A refrigerant. Residual mineral oil can
act as an insulator, preventing proper heat trans-
fer. It can also clog the expansion device, and re-
duce the system performance and capacity.
Failure to properly flush the system per the in-
structions below will void the warranty.
Required Equipment
Equipment required to flush the existing line set and indoor
coil:
Stwo clean R−22 recovery bottles,
Soil−less recovery machine with pump-down feature,
S2 gauge sets (one for R−22; one for R−410A).
Flushing Procedure
IMPORTANT
The Environmental Protection Agency (EPA) pro-
hibits the intentional venting of HFC refrigerants
during maintenance, service, repair and disposal of
appliance. Approved methods of recovery, recycl-
ing or reclaiming must be followed.
1. Remove existing R−22 refrigerant using the following,
appropriate procedure (see figure 13):
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 R−22 refrigerant
to flush the system −
DDisconnect all power to the existing outdoor unit.
DConnect to the existing unit, a clean recovery cyl-
inder and the recovery machine according to the
instructions provided with the recovery machine.
DRemove all R−22 refrigerant from the existing sys-
tem. Check gauges after shutdown to confirm that
the entire system is completely void of refrigerant.
DDisconnect the liquid and vapor lines from the ex-
isting outdoor unit.
If the existing outdoor unit is equipped with
manual shut−off valves AND you plan to use NEW
R−22 refrigerant to flush the system −
DStart the existing R−22 system in the cooling mode
and close the liquid line valve.
DPump all of the existing R−22 refrigerant back into
the outdoor unit. (It may be necessary to bypass
the low pressure switches to ensure complete re-
frigerant evacuation.)
DWhen the low side system pressures reach 0 psig,
close the vapor line valve.
DDisconnect all power to the existing outdoor unit.
Check gauges after shutdown to confirm that the
valves are not allowing refrigerant to flow back into
the low side of the system.
DDisconnect the liquid and vapor lines from the ex-
isting outdoor unit.
2. Remove the existing outdoor unit. Set the new R−410A
unit and follow the brazing connection procedure (see
page 7) to make line set connections.

Page 10
505095M 1/3/06
Flushing Connections
Low
Pressure
High
Pressure
Vapor Line
Service Valve
EXISTING
INDOOR COIL
XC15
UNIT
GAUGE MANIFOLD
Inverted R−22 Cylinder
(Contains clean R−22 to
be used for flushing)
Liquid Line
Service Valve
Inlet
Discharge
Tank Return
ClosedOpened
EXISTING LIQUID LINE
RECOVERY CYLINDER
NOTE − The inverted R−22 cylinder
must contain at least the same
amount of refrigerant as was recov-
ered from the existing system.
Figure 13
EXISTING VAPOR LINE
RECOVERY MACHINE
3. Make low voltage and line voltage connections to the
new outdoor unit. Do NOT turn on power to unit or
open the outdoor unit service valves at this time.
4. Remove the existing refrigerant flow control orifice or
thermal expansion valve before continuing with flush-
ing procedures. Existing devices are not approved for
use with R−410A refrigerant and may prevent proper
flushing. Use a field−provided fitting to reconnect lines.
IMPORTANT
The line set and indoor 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.
5. Remove the pressure tap valve cores from the XC15
unit’s service valves. Connect an R−22 cylinder with
clean refrigerant to the vapor service valve. Connect
the R−22 gauge set to the liquid line valve. Connect a
recovery machine with an empty recovery tank to the
gauge set.
6. Set 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 ex-
isting system line set and indoor coil.
7. Invert the cylinder of clean R−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 coil
before it enters the recovery machine.
8. After all of the liquid refrigerant has been recovered,
switch the recovery machine to vapor recovery so that
all of the R−22 vapor is recovered. Allow the recovery
machine to pull a vacuum on the system.
NOTE − A single system flush should remove all of the
mineral oil from the existing refrigerant lines and in-
door coil. A second flushing may be done (using clean
refrigerant) if insufficient amounts of mineral oil were
removed during the first flush. Each time the system
is flushed, you must allow the recovery machine
to pull a vacuum on the system at the end of the
procedure.
9. Close the valve on the inverted R−22 drum and the
gauge set valves. Pump the remaining refrigerant out
of the recovery machine and turn the machine off.
10. Use dry nitrogen to break the vacuum on the refriger-
ant lines and indoor coil before removing the recovery
machine, gauges and R−22 refrigerant drum. Reinstall
pressure tap valve cores into XC15 service valves.
11. Install the expansion valve in the liquid line at the in-
door coil.
Refrigerant Metering Device
XC15 units may be used in thermal expansion valve (TXV)
systems only. See the indoor coil installation instructions
and the Lennox Engineering Handbook for approved TXV
match−ups and application information. Table 2 (on
Page 6) lists liquid and vapor line sizes and correspond-
ing line sets.
Expansion valves equipped with Chatleff type fittings are
available from Lennox. Refer to the Engineering Hand-
book for expansion valves for use with specific match−ups.
If you install an expansion valve with an indoor coil that in-
cludes a fixed orifice, remove the orifice before the expan-
sion valve is installed (see figure 14).