Lennox XC15, XC15-024, XC15-030, XC15-036, XC15-042 Installation Instructions Manual

INSTALLATION

E2008 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.

INSTRUCTIONS

Dave Lennox Signature
Collection XC15 Units

AIR CONDITIONER

506044−01
06/08
Supersedes 04/08

Table of Contents

Shipping and Packing List 1. . . . . . . . . . . . . . . . . . . . . .

XC15 Outdoor Unit 3. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unit Dimensions and Parts Arrangement 2. . . . . . . . .

General Information 3. . . . . . . . . . . . . . . . . . . . . . . . . . .

Recovering Refrigerant from Existing System 5. . . . .

Removing Existing Outdoor Unit 5. . . . . . . . . . . . . . . . .

Positioning New Outdoor Unit 5. . . . . . . . . . . . . . . . . . .

Removing and Installing Panels 7. . . . . . . . . . . . . . . . .

New or Replacement Line Set 8. . . . . . . . . . . . . . . . . . .

Brazing Line Set Connections 9. . . . . . . . . . . . . . . . . . .

Removing Indoor Unit Metering Device 11. . . . . . . . . . .

Flushing System 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Installing New Indoor Unit Metering Device 13. . . . . . . .

Testing for Leaks 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Evacuating the System 15. . . . . . . . . . . . . . . . . . . . . . . . .

Servicing Unit Delivered Void of Charge 15. . . . . . . . . . .

Electrical Connection 15. . . . . . . . . . . . . . . . . . . . . . . . . .

Start−Up and Charging Procedures 16. . . . . . . . . . . . . . .

System Operation 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lennox System Operation Monitor (LSOM) 20. . . . . . .

Maintenance 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sound Reduction Cover and Assembly Procedure 23. .

Homeowner Information 23. . . . . . . . . . . . . . . . . . . . . . . .

Optional Accessories 24. . . . . . . . . . . . . . . . . . . . . . . . . .

Start−Up and Performance Checklist 24. . . . . . . . . . . . .

Shipping and Packing List

®

Litho U.S.A.

This unit must be matched with an indoor coil as
specified in Lennox Engineering Handbook. Coils
previously charged with HCFC−22 must be
flushed.

IMPORTANT

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.

06/08 506044−01

*2P0608* *P506044-01*

Check the unit for shipping damage and listed times below
are intact. If damaged, or if parts are missing, immediately
contact the last shipping carrier.

1  Assembled outdoor unit.
1  Bag Assembly

S 1  Bushing (for low voltage wiring
S 2  Isolation grommets for liquid and suction

lines.

ISOLATION GROMMETS (2)

Figure 1. Bag Assembly (Parts)

Page 1

BUSHING (1)

Unit Dimensions − Inches (mm) and Parts Arrangement

39.40"
(1003)

UNIT SUPPORT FEET

16−7/8

(429)

8−3/4
(222)

3−1/8

(79)

DISCHARGE AIR

SIDE VIEW

30−3/4

(781)

SUCTION LINE
INLET

LIQUID LINE
INLET

26−7/8

(683)

3−3/4 (95)

4−5/8
(117)

ELECTRICAL

INLETS

[−024] 41 (1040)

[−030 THROUGH −060]

47 (1194)

CONTACTOR

SYSTEM OPERATION

SUCTION VALVE AND

MONITOR

RUN CAPACITOR

DISCHARGE LINE

MUFFLER

GAUGE PORT

SUCTION LINE

LOW PRESSURE

SWITCH

FILTER DRIER

18.60"
(470)

8.00"
(203)

1 (25)

35.50"
(902)

ACCESS VIEW

OUTDOOR FAN

COMPRESSOR
AND SOUND
REDUCTION
COVER

COMPRESSOR
TERMINAL PLUG

HIGH PRESSURE
SWITCH

BASE WITH ELONGATED LEGS

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

506044−01 06/08

Page 2

XC15 PARTS ARRANGEMENT

VIBRATION ISOLATOR SLEEVE
LOCATIONS ON −024, −030 AND

−036.

NOTE: ON THE −042, ALL THREE
VIBRATION ISOLATOR
SLEEVES ARE LOCATED ON
THE HORIZONTAL SECTION OF
THE DISCHARGE LINE.

DO NOT REMOVED THE THREE VIBRATION ISOLATOR SLEEVES (IF

PRESENT) FROM THE COMPRESSOR DISCHARGE LINE

Figure 1. Discharge Line Vibration Isolators

XC15 Outdoor Unit

The XC15 Air Conditioners, 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
XC15 Engineering Handbook.

This outdoor unit is designed for use in systems that use
thermal expansion valve (TXV) refrigerant metering
devices.

General Information

These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
who have jurisdiction before installation.

When servicing or repairing HVAC components, ensure
caps and fasteners are appropriately tightened. Table 1
lists torque values for typical service and repair items.

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 #10 28 in.− lb. 3 NM

Compressor bolts 90 in.− lb. 10 NM

Gauge port seal cap 8 ft.− lb. 11 NM

USING MANIFOLD GAUGE SETS

When checking the system charge, only use a manifold
gauge set that features low−loss anti−blow back fittings.
See figure 4 for a typical manifold gauge connection setup.

Manifold gauge sets 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 on the high side and a low side of
30" vacuum to 250 psi with dampened speed to 500 psi.
Gauge hoses must be rated for use at up to 800 psi of
pressure with a 4000 psi burst rating.

OPERATING SERVICE VALVES

The liquid and suction line service valves are used for
removing refrigerant, flushing, leak testing, evacuating,
checking charge and charging.

Each service valve is equipped with a service port which
has a factory−installed valve stem.

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.

1/12 TURN

12

1

2

3

4

7

5

6

9

10

8

11

1/6 TURN

12

1

2

3

4

7

5

6

11

10

9

8

Figure 2. Cap Tightening Distances

NOTE − A label with specific torque requirements may be
affixed to the stem cap. If the label is present, use the
specified torque.

IMPORTANT

To prevent stripping of the various caps used, the
appropriately sized wrench should be used and
fitted snugly over the cap before tightening.

To Access Angle−Type Service Port:

A service port cap protects the service port core from
contamination and serves as the primary leak seal.

SERVICE PORT CAP

STEM CAP

SERVICE PORT

(VALVE STEM SHOWN
CLOSED) INSERT HEX
WRENCH HERE

SERVICE PORT

CLOSED TO BOTH

INDOOR AND

OUTDOOR UNITS

FRONT-SEATED

CORE

VALVE STEM

TO INDOOR

UNIT

TO OUTDOOR UNIT

Figure 3. Angle−Type Service Valve

(Font−Seated Closed)

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:

S With Torque Wrench: Finger tighten and then

tighten per table 1.

S Without Torque Wrench: Finger tighten and use an

appropriately sized wrench to turn an additional
1/6 turn clockwise as illustrated in figure 2.

To Open and Close Angle−Type Service Valve:

A valve stem cap protects the valve stem from
contamination and assures a leak−free seal.

Page 3

XC15 SERIES

OUTDOOR UNIT

(Uncased Coil Shown)

LOW

PRESSURE

GAUGE MANIFOLD

PRESSURE

TO

HFC−410A

DRUM

HIGH

FILTER

DRIER

LIQUID LINE

SERVICE VALVE

COMPRESSOR

Figure 4. Typical Manifold Gauge Connection Setup

SERVICE PORT CAP

SERVICE PORT

CORE

OPEN TO BOTH

INDOOR AND

OUTDOOR UNITS

TO INDOOR

UNIT

TO OUTDOOR UNIT

STEM CAP

SERVICE PORT

(VALVE STEM SHOWN OPEN)
INSERT HEX WRENCH HERE

Figure 5. Angle−Type Service Valve

(Back−Seated Opened)

1. Remove stem cap with a wrench.

2. Use a service wrench with a hex−head extension
(3/16" for liquid-line valve sizes and 5/16" for
suction-line valve sizes) to back the stem out
counterclockwise as far as it will go.

3. Replace the stem cap and tighten as follows:

S With Torque Wrench: Tighten finger tight and then

tighten per table 1.

S Without Torque Wrench: Finger tighten and use an

appropriately sized wrench to turn an additional
1/12 turn clockwise as illustrated in figure 2.

To Access Ball−Type 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:

OUTDOOR

COIL

SUCTION LINE
SERVICE VALVE

TXV

S With Torque Wrench: Finger tighten and then

tighten per table 1.

S Without Torque Wrench: Finger tighten and use an

appropriately sized wrench to turn an additional
1/6 turn clockwise as illustrated in figure 2.

To Open and Close Ball−Type Service Valve:

A valve stem cap protects the valve stem from
contamination and assures a leak−free seal.

1. Remove stem cap with a wrench.

2. Use an appropriately sized wrench to open. To open
valve, rotate stem counterclockwise 90°. To close
rotate stem clockwise 90°.

3. Replace the stem cap and tighten as follows:

S With Torque Wrench: Finger tighten and then

tighten per table 1.

S Without Torque Wrench: Finger tighten and use an

appropriately sized to wrench turn an additional
1/12 turn clockwise as illustrated in figure 2.

OPEN TO LINE SET WHEN VALVE IS
CLOSED, TO BOTH LINE SET AND
UNIT WHEN VALVE IS OPEN.

TO OPEN ROTATE STEM
COUNTERCLOCKWISE
90°.

TO CLOSE ROTATE
STEM CLOCKWISE 90°.

SERVICE

PORT

SERVICE

PORT CORE

SERVICE PORT

TO OUTDOOR UNIT

CAP

Figure 6. Ball−Type Service Valve

TO INDOOR UNIT

BALL
(SHOWN
CLOSED)

VALV E
STEM

STEM

CAP

506044−01 06/08

Page 4

Recovering Refrigerant from Existing
System

Remove existing HCFC−22 refrigerant using one of the
following methods:

METHOD 1:

Use this method if the existing outdoor unit is not equipped
with manual shut−off valves, and plan on using existing
HCFC−22 refrigerant to flush the system.

NOTE − Use recovery machine instructions for specific
setup requirements.

Perform the following task:

1. Disconnect all power to the existing outdoor unit.

2. Connect to the existing unit a gauge set, clean
recovery cylinder and a recovery machine. Use the
instructions provided with the recover machine on how
to setup the connections.

3. Remove all HCFC−22 refrigerant from the existing
system. Check gauges after shutdown to confirm that
the entire system is completely void of refrigerant.

RECOVERY MACHINE

MANIFOLD GAUGES

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 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.

CLEAN RECOVERY
CYLINDER

OUTDOOR UNIT

Figure 7. Typical Refrigerant Recovery

(Method 1)

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 sets. The following
conditions may cause the compressor to stop functioning:

The following devices could prevent full system charge
recovery into the outdoor unit:

S Outdoor unit’s high or low−pressure switches (if

applicable) when tripped can cycled the compressor
OFF.

S Compressor can stop pumping due to tripped internal

pressure relief valve.

S Compressor 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

Removing Existing Outdoor Unit

Perform the following task at the existing outdoor unit:

S Disconnect line set at the service valves.
S Disconnect electrical service at the disconnect switch.
S Remove old outdoor unit.

Positioning New Outdoor Unit

CAUTION

In order to avoid injury, take proper precaution when
lifting heavy objects.

See Unit Dimensions on page 2 for sizing mounting slab,
platforms or supports. Refer to figure 8 for mandatory
installation clearance requirements.

CONTROL PANEL
ACCESS LOCATION

*

Page 5

*

*

* SEE NOTES ON NEXT PAGE FOR FURTHER DETAILS.

Figure 8. Installation Clearances

*

XC15 SERIES

NOTES:

S Service clearance of 30 in. (762 mm) must be

maintained on one of the sides adjacent to the control
box.

S Clearance to one of the other three sides must be 36

in. (914 mm)

.

S Clearance to one of the remaining two sides may be

12 in. (305 mm) and the final side may be 6 in. (152

.

mm)

S 48 in. (1219 mm) clearance required on top of unit.
S A clearance of 24 in. (610 mm) must be maintained

between two units.

POSITIONING CONSIDERATIONS

Consider the following when positioning the unit:

BUILDING

STRUCTURE

MOUNTING
SLAB

GROUND LEVEL

Figure 10. Slab Mounting at Ground Level

NOTE − If necessary for stability, anchor unit to slab as
described in Stabilizing Unit on Uneven Surfaces on page

7.

INSTALL UNIT

AWAY FROM

WINDOWS

TWO 90° ELBOWS INSTALLED IN

LINE SET WILL REDUCE LINE SET

VIBRATION.

Figure 9. Outside Unit Placement

S Some 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.

S When 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 9.

PLACING OUTDOOR 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 10.

NOTE − 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.

ELEVATING THE UNIT

Unlike the small−base units which use round support feet,
the larger−base units are outfitted with elongated support
feet as illustrated in figure 11 which uses a similar method
for elevating the unit.

If additional elevation is necessary, raise the unit by
extending the length 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.

BASE

LEG DETAIL

2" (50.8MM) SCH 40
FEMALE THREADED
ADAPTER

Figure 11. Elevated Slab Mounting using

Feet Extenders (Larger Base Units)

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.

506044−01 06/08

Page 6

STABILIZING UNIT ON UNEVEN SURFACES

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.

With unit positioned at installation site, remove two side
louvered panels to expose the unit base pan. Install the
brackets as illustrated in figure 12 using conventional

practices; replace the panels after installation is complete.

Slab Side Mounting

#10 1/2" LONG SELF−

DRILLING SHEET

METAL SCREWS

STABILIZING

BRACKET (18 GAUGE

METAL − 2" WIDTH;

HEIGHT AS REQ’D)

#10 1−1/4" LONG

HEX HD SCREW

AND FLATWASHER

COIL

BASE PAN

CORNER POST

Removing and Installing Panels

ACCESS PANEL

Remove and reinstall access panel as shown in figure 13.

REMOVE 4 SCREWS TO REMOVE PANEL
FOR ACCESSING COMPRESSOR AND
CONTROLS.

INSTALL BY POSITIONING PANEL WITH
HOLES ALIGNED; INSTALL SCREWS AND
TIGHTEN.

Figure 13. Access Panel

CAUTION

CONCRETE SLAB − USE PLASTIC
PLASTIC ANCHOR (HOLE DRILL
1/4")PLASTIC SLAB − NO PLASTIC
ANCHOR (HOLE DRILL 1/8")

STABILITY

MINIMUM 1
PER SIDE

Deck Top

Mounting

STABILIZING BRACKET
(18 GAUGE METAL − 2"
WIDTH; HEIGHT AS
REQ’D); BEND TO FORM
RIGHT ANGLE

ONE BRACKET PER SIDE (MIN.); FOR EXTRA STABILITY,
2 BRACKETS PER SIDE, 2" FROM EACH CORNER.

FOR EXTRA

Figure 12. Installing Stabilizer Brackets

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.

ROOF MOUNTING

Install unit at a minimum of four 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
redwood or steel supports are recommended.

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.

INSTALLING ISOLATION GROMMETS

Locate the isolation grommets (provided). Slide grommets
onto suction and liquid lines. Insert grommets into mullion
to isolate refrigerant lines from sheet metal edges.

REMOVING PANELS

Remove the louvered panels as follows:

1. Remove two screws, allowing the panel to swing open
slightly as illustrated in figure 14.

NOTE − Hold the panel firmly throughout this procedure

2. Rotate bottom corner of panel away from hinge corner
post until lower three tabs clear the slots as illustrated
in figure 14, detail B.

3. Move panel down until lip of upper tab clears the top
slot in corner post as illustrated in figure 14, detail A.

Page 7

XC15 SERIES

INSTALLING PANEL

Install unit at a minimum of four inches above the surface
of the roof. Care must be taken to ensure weight of unit is
properly distributed over roof joists and rafters.

IPANEL SHOWN SLIGHTLY ROTATED TO ALLOW TOP TAB TO EXIT (OR ENTER) TOP
SLOT FOR REMOVING (OR INSTALLING) PANEL.

SCREW

LIP

HOLES

2. With a continuous motion slightly rotate and guide the
lip of top tab inward as illustrated in figure 14, details
A and C, then upward into the top slot of the hinge
corner post.

3. Rotate panel to vertical to fully engage all tabs.

4. Holding the panel’s hinged side firmly in place, close
the right−hand side of the panel, aligning the screw
holes.

5. When panel is correctly positioned and aligned, insert
the screws and tighten.

DETAIL A

DETAIL B

ROTATE IN THIS DIRECTION; THEN DOWN TO REMOVE PANEL

DETAIL C

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 14. Removing/Installing Louvered

Panels (Details A, B and C)

MAINTAIN MINIMUM PANEL ANGLE (AS CLOSE TO PARALLEL WITH THE UNIT
AS POSSIBLE) WHILE INSTALLING PANEL.

ANGLE MAY BE

TOO EXTREME

PREFERRED ANGLE

FOR INSTALLATION

DETAIL D

HOLD DOOR FIRMLY TO THE
HINGED B SIDE TO MAINTAIN
FULLY−ENGAGED TABS

Figure 15. Removing/Installing Louvered

Panels (Detail D)

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 9.

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.

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.

MATCHING WITH NEW OR EXISTING INDOOR COIL
AND LINE SET

IMPORTANT

Matching XC15 with a New Indoor Coil and Line
SetIf installing a new indoor coil and reusing the
existing line set that included a RFCI liquid line
(small bore liquid line used as a metering device)
then you must change to a standard size liquid line.

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:

S Model (XC15) and size of unit (e.g. −060).

Install the louvered panels as follows:

1. Position the panel almost parallel with the unit as
illustrated in figure 15, detail D with the screw side as
close to the unit as possible.

506044−01 06/08

S Line set diameters for the unit being installed as listed

in table 2 and total length of installation.

S Number of elbows and if there is a rise or drop of the

piping.

Page 8

Table 2. Refrigerant Line Set

Model

−024

−030

−036

−042

−048

−060

Field
Connections

Liquid
Line

3/8 in.

(10 mm)

3/8 in.

(10 mm)

3/8 in.

(10 mm)

Vapor
Line

3/4 in.

(19 mm)

7/8 in

(22 mm)

1−1/8 in.
(29 mm)

Recommended Line Set

Liquid
Line

3/8 in

(10 mm)

3/8 in.

(10 mm)

3/8 in.

(10 mm)

Vapor
Line

3/4 in.

(19 mm)

7/8in

(22 mm)

1−1/8 in.
(29 mm)

L15
Line Sets

L15−41
15 − 50 ft.
(5 − 15 m)

L15−65
15 − 50 ft.
(5 − 15m)

Field

Fabricated

If the XC15 is being used with either a new or existing
indoor coil which is equipped with a liquid line which served
as a metering device (RFCI), the liquid line must be
replaced prior to the installation of the XC15 unit. Typically
a liquid line used to meter flow is 1/4" in diameter and
copper.

INSTALLING LINE SET
Line Set IsolationThis reference illustrates

procedures, which ensure proper refrigerant line set
isolation:

S Installation of line set on horizontal runs is

illustrated in figure 16.

S Installation of a transition from horizontal to

vertical is illustrated in figure 17.

S Installation of line set on vertical runs is illustrated in

figure 18.

TO HANG LINE SET FROM JOIST OR
RAFTER, USE EITHER METAL STRAPPING
MATERIAL OR ANCHORED HEAVY NYLON
WIRE TIES.

STRAPPING MATERIAL

(AROUND SUCTION

LINE ONLY)

FLOOR JOIST OR

ROOF RAFTER

TAPE OR

WIRE TIE

8 FEET

FLOOR JOIST OR

ROOF RAFTER

METAL

SLEEVE

8 FEET

STRAP THE SUCTION LINE TO
THE JOIST OR RAFTER AT 8 FEET
INTERVALS THEN STRAP THE
LIQUID LINE TO THE SUCTION
LINE.

WIRE TIE
(AROUND
SUCTION LINE
ONLY)

TAPE OR

WIRE TIE

AUTOMOTIVE

STRAP LIQUID LINE
TO SUCTION LINE

LIQUID LINE

SUCTION LINE − WRAPPED
IN ARMAFLEX

ANCHORED HEAVY NYLON
WIRE TIE OR AUTOMOTIVE
MUFFLER-TYPE HANGER

WALL
STUD

METAL SLEEVE

MUFFLER-TYPE HANGER

Figure 17. Refrigerant Line Set: Transition

from Vertical to Horizontal

IMPORTANT - REFRIGERANT LINES MUST NOT CONTACT WALL.

OUTSIDE WALL

WOOD BLOCK

BETWEEN STUDS

NOTE − SIMILAR INSTALLATION
PRACTICES SHOULD BE USED
IF LINE SET IS TO BE INSTALLED
ON EXTERIOR OF OUTSIDE
WALL.

OUTSIDE

WALL

CAULK

PVC PIPE FIBERGLASS INSULATION

SUCTION LINE

SLEEVE

SUCTION LINE WRAPPED WITH
ARMAFLEX

LIQUID LINE

IMPORTANT! REFRIGERANT
LINES MUST NOT CONTACT

STRUCTURE.

Figure 18. Refrigerant Line Set: Installing
Vertical Runs (New Construction Shown)

Brazing Line Set Connections

LIQUID

LINE

WIRE TIE

INSIDE WALL

STRAP

SLEEVE

WIRE TIE

WOOD BLOCK

WIRE TIE

STRAP

Figure 16. Refrigerant Line Set: Installing

Horizontal Runs

Use the following procedure to braze the line set to the new
air conditioner unit. Figure 19 on page 10 is provided as a
general guide for preparing to braze the line set to the air
conditioner unit.

Page 9

XC15 SERIES

1

2

3

CUT AND DEBUR

7

INSTALL CORE ONLY FOR

BOTH SERVICE PORTS AFTER

THEY HAVE COOLED.

INDOOR UNIT

6

BRAZE LINE SET

REMOVE CAP AND CORE FROM

BOTH LIQUID AND SUCTION

SERVICE PORTS

SERVICE PORT MUST BE

OPEN TO ALLOW EXIT

POINT FOR NITROGEN

SUCTION LINE

LIQUID LINE

Figure 19. Brazing Connections

BRAZING CONNECTION PROCEDURE

Before brazing, remove the access panel as illustrated in
figure 13; then remove the narrow piping panel to prevent
burning off the paint as illustrated in figure 20.

ATTACH

GAUGES

SERVICE

5

VALVE

SERVICE

VALVE

OUTDOOR

UNIT

FLOW NITROGEN

NITROGEN

4

WRAP

SERVICE

VALV E

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.

LINE SET

CONNECTION

POINTS.

REMOVE 2 SCREWS
AND REMOVE PANEL
BEFORE BRAZING.

PIPING
PANEL

Figure 20. Piping Panel Removal

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

Danger of fire. Bleeding the
refrigerant charge from only the high
side may result in the low side shell
and suction tubing being
pressurized. Application of a brazing
torch while pressurized may result in
ignition of the refrigerant and oil
mixture − check the high and low
pressures before unbrazing.

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. Remove service cap and core from both the suction
and liquid line service ports.

3. Connect gauge low pressure side to liquid line service
valve.

4. To protect components during brazing, wrap a wet
cloth around the liquid line service valve body and
copper tube stub and use another wet cloth
underneath the valve body to protect the base paint.
Also, shield the light maroon HFC−410A sticker.

506044−01 06/08

Page 10

5. Flow regulated nitrogen (at 1 to 2 psig) through the
refrigeration gauge set into the valve stem port
connection on the liquid line service valve and out of
the valve stem port connection on the suction service
valve.

NOTE − The TXV metering device at the indoor unit will
allow low pressure nitrogen to flow through the system.)

NOTE − Use silver alloy brazing rods with five or six percent
minimum silver alloy for copper−to−copper brazing or 45
percent silver alloy for copper−to−brass or copper−to−steel
brazing.

6. Braze the liquid line to the liquid line service valve.
Turn off nitrogen flow.

IMPORTANT

Repeat procedure starting at paragraph 4 for brazing the
suction line to service port valve.

7. After all connections have been brazed, disconnect
manifold gauge set the from service ports and remove
wrapping. Reinstall the service port core for both of the
outdoor unit’s service valves.

Removing Indoor Unit Metering Device

Remove the existing HCFC−22 fixed orifice or TXV from
the indoor coil. The existing indoor unit HCFC−22 metering
device is not approved for use with HFC−410A refrigerant
and may prevent proper flushing.

REPLACEMENT PARTS

If replacement parts are necessary for the indoor unit,
order kit 69J46 (LB−95325A). The kit includes:

LIQUID LINE ORIFICE HOUSINGS (10)

TEFLON RINGS (20)

LIQUID LINE ASSEMBLIES

(INCLUDES STRAINER) (10)

BRASS NUTS (10)

Figure 21. 69J46 Kit Components

LIQUID LINE

ASSEMBLY

PISTON
RETAINER

STRAINER

COPPER
TUBE

TYPICAL FIXED ORIFICE REMOVAL PROCEDURE

DISTRIBUTOR

ASSEMBLY

DISTRIBUTOR TUBES

LIQUID LINE ORIFICE HOUSING

TEFLON RING

VALVE STEM

VALVE STEM CAP

(Uncased Coil Shown)

REMOVE AND DISCARD
FIXED
ORIFICE

VALVE STEM ASSEMBLY

(IF PRESENT)

BRASS NUT

LIQUID LINE ASSEMBLY

(INCLUDES STRAINER)

Figure 22. Typical Fixed Orifice Removal

1. On fully cased coils, remove the coil access and
plumbing panels.

2. Remove any shipping clamps holding the liquid line
and distributor assembly.

3. Using two wrenches, disconnect liquid line from liquid
line orifice housing. Take care not to twist or damage
distributor tubes during this process.

4. Remove and discard fixed orifice, valve stem
assembly if present and Teflon ring as illustrated in
figure 22.

5. Use a field−provided fitting to temporary reconnect the
liquid line to the indoor unit’s liquid line orifice housing.

TYPICAL TXV REMOVAL PROCEDURE

1. On fully cased coils, remove the coil access and
plumbing panels.

2. Remove any shipping clamps holding the liquid line
and distributor assembly.

3. Disconnect the equalizer line from the TXV equalizer
line fitting on the suction line.

4. Remove the suction line sensing bulb as illustrated in
figure 23.

5. Disconnect the liquid line from the TXV at the liquid line
assembly.

Page 11

XC15 SERIES

TWO PIECE

PATCH PLATE

(UNCASED COIL

ONLY)

DISTRIBUTOR

TUBES

DISTRIBUTOR

ASSEMBLY

MALE EQUALIZER

LINE FITTING

LIQUID LINE

ORIFICE

HOUSING

EQUALIZER
LINE

SENSING

BULB

STUB END

TXV

TEFLON
RING

LIQUID LINE ASSEMBLY

WITH BRASS NUT

SUCTION

LINE

TEFLON

RING

SENSING

LINE

LIQUID

LINE

Figure 23. Typical TXV Removal

6. Disconnect the TXV from the liquid line orifice housing.
Take care not to twist or damage distributor tubes
during this process.

7. Remove and discard TXV and the two Teflon rings as
illustrated in figure 23.

8. Use a field−provided fitting to temporary reconnect the
liquid line to the indoor unit’s liquid line orifice housing.

Flushing the System

(Uncased Coil Shown)

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.

If the original system used:

S HCFC−22 refrigerant, then flush the system using the

procedure provided in this section.

S HFC−410A refrigerant, then proceed to Installing New

Refrigerant Metering Device.

INVERTED HCFC−22 CYLINDER
CONTAINS CLEAN HCFC−22 TO
BE USED FOR FLUSHING.

SUCTION LINE

SERVICE VALVE

EXISTING

INDOOR

UNIT

LIQUID LINE SERVICE VALVE

RECOVERY

CYLINDER

SUCTION

LIQUID

NOTE − The inverted HCFC−22 cylinder must contain at least the same
amount of refrigerant as was recovered from the existing system.

NEW

OUTDOOR

UNIT

OPENED

RECOVERY MACHINE

Figure 24. Typical Flushing Connection

MANIFOLD

LOW

PRESSURE

TANK
RETURN

INLET

DISCHARGE

GAUGE

PRESSURE

HIGH

CLOSED

CAUTION

IMPORTANT

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.

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.

506044−01 06/08

This procedure should not be performed on
systems which contain contaminants (Example:
compressor burn out).

REQUIRED EQUIPMENT

Equipment required to flush the existing line set and indoor
unit coil:

S Two clean HCFC−22 recovery bottles,
S Oilless recovery machine with pump-down feature,
S Two gauge sets (one for HCFC−22; one for

HFC−410A).

PROCEDURE

1. Connect the following:

S HCFC−22 cylinder with clean refrigerant to the

suction service valve,

S HCFC−22 gauge set to the liquid line valve,
S Recovery machine with an empty recovery tank to

the gauge set.

2. 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
existing system line set and indoor unit coil.

Page 12

3. Invert the cylinder of clean HCFC−22 and open its
valve to allow liquid refrigerant to flow into the system
through the suction 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.

4. After all of the liquid refrigerant has been recovered,
switch the recovery machine to suction recovery so
that all of the HCFC−22 suction is recovered. Allow the
recovery machine to pull a vacuum on the system.

5. Close 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.

6. Use dry nitrogen to break the vacuum on the
refrigerant lines and indoor unit coil before removing
the recovery machine, gauges and refrigerant drum.

Installing New Indoor Unit Metering
Device

XC15 units are designed with HFC−410A TXV metering
devices. This section provides instructions on installing
TXV refrigerant metering device.

9

10

8

11

1/8 TURN

12

1

2

3

10

9

4

7

5

6

12

11

8

7

6

1/2 TURN

1

2

3

4

5

TYPICAL TXV INSTALLATION PROCEDURE

The TXV 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 TXV in a
manner that will provide access for field servicing of the
TXV. Refer to Figure 27 for reference during installation of
TXV unit.

To prevent any possibility of water damage, properly
insulate all parts of the TXV assembly that may sweat due
to temperature differences between the valve and its
surrounding ambient temperatures.

1. Remove the field−provided fitting that temporary
reconnected the liquid line to the indoor unit’s
distributor assembly.

2. Install one of the provided Teflon rings around the
stubbed end of the TXV and lightly lubricate the
connector threads and expose surface of the Teflon
ring with refrigerant oil.

3. Attach the stubbed end of the TXV 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 figure 25, or 20 ft−lb.

4. Place the remaining Teflon ring around the other end
of the TXV. Lightly lubricate connector threads and
expose surface of the Teflon ring with refrigerant oil.

TWO PIECE

PATCH PLATE

(UNCASED COIL

ONLY)

DISTRIBUTOR

TUBES

(Uncased Coil Shown)

LIQUID LINE

ORIFICE

HOUSING

STUB END

TXV

TEFLON

RING

Figure 25. Tightening Distance

XC15 ENGINEERING HANDBOOK

See the XC15 Engineering Handbook for approved
indoor/outdoor match−ups, applicable TXV kits and
application information.

The following is the typical contents of a TXV kit:

TXV (1)

HEX HEAD BOLTS

AND NUTS (2)

TEFLON
RINGS (2)

COPPER

MOUNTING

STRAP (1)

Figure 26. TXV Kit Components

TEFLON

DISTRIBUTOR

ASSEMBLY

MALE EQUALIZER LINE

FITTING (SEE FIGURE 29
FOR FURTHER DETAILS)

SENSING BULB INSULATION IS
REQUIRED IF MOUNTED EXTERNAL
TO THE COIL CASING. SEE FIGURE 28
FOR BULB POSITIONING.

EQUALIZER
LINE

RING

LIQUID LINE ASSEMBLY

WITH BRASS NUT

SUCTION
LINE

SENSING

LINE

LIQUID

LINE

Figure 27. Typical TXV Installation

5. Attach the liquid line assembly to the TXV. Finger
tighten and use an appropriately sized wrench to turn
an additional 1/2 turn clockwise as illustrated in figure
25, or 20 ft−lb.

Page 13

XC15 SERIES

6. Attach the suction line sensing bulb in the proper
orientation as illustrated in figure 28 using the clamp
and screws provided.

NOTE − Insulating the sensing bulb once installed may be
required when the bulb location is external to the coil
casing.

SUCTION LINE

BULB

SUCTION LINE

BULB

12

12

BULB

BULB

ON LINES SMALLER THAN
7/8", MOUNT SENSING BULB
AT EITHER THE 3 OR 9
O’CLOCK POSITION.

ON 7/8" AND LARGER LINES,
MOUNT SENSING BULB AT
EITHER THE 4 OR 8 O’CLOCK
POSITION. NEVER MOUNT
ON BOTTOM OF LINE.

NOTE − NEVER MOUNT ON BOTTOM OF
LINE.

Figure 28. TXV Sensing Bulb Installation

7. Remove and discard either the flare seal cap or flare
nut with copper flare seal bonnet from the equalizer
line port on the suction line as illustrated in figure 29.

IMPORTANT

When removing the flare nut, ensure that the copper
flare seal bonnet is removed.

FLARE SEAL

CAP

OR

MALE BRASS EQUALIZER

Figure 29. Copper Flare Seal Bonnet Removal

8. Connect the equalizer line from the TXV to the
equalizer suction port on the suction line. Finger
tighten the flare nut plus 1/8 turn (7 ft−lbs) as illustrated
in figure 25.

Testing for Leaks

After the line set has been connected to both the indoor
and outdoor units, check the line set connections and
indoor unit for leaks. Use the following procedure to test for
leaks:

506044−01 06/08

FLARE NUT

COPPER

FLARE SEAL

BONNET

LINE FITTING

SUCTION LINE

IMPORTANT

Leak detector must be capable of sensing HFC
refrigerant.

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.

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 damage by fire and/
or an explosion, that could result in
personal injury or death.

1. Connect an HFC−410A manifold gauge set high
pressure hose to the suction valve service port.

NOTE − Normally, the high pressure hose is connected to
the liquid line port; however, connecting it to the suction
port better protects the manifold gauge set from high
pressure damage.

2. With 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 (suction only).

3. Open 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.

4. Connect a cylinder of dry nitrogen with a pressure
regulating valve to the center port of the manifold
gauge set.

5. Adjust 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.

6. After 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.

NOTE − Amounts of refrigerant will vary with line lengths.

7. Check all joints for leaks.

8. Purge dry nitrogen and HFC−410A mixture.

9. Correct any leaks and recheck.

Page 14

10. After leak testing disconnect gauges from service
ports.

Evacuating the System

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.

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.

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.

1. Connect manifold gauge set to the service valve ports
as follows:

S low pressure gauge to suction line service valve
S high pressure gauge to liquid line service valve

2. Connect micron gauge.

3. Connect the vacuum pump (with vacuum gauge) to
the center port of the manifold gauge set.

4. Open both manifold valves and start the vacuum
pump.

5. Evacuate 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 to
determine if there is a rapid rise in sure 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.

6. When the absolute pressure reaches 23,000 microns
(29.01 inches of mercury), close the manifold gauge
valves, turn off the vacuum pump and disconnect the
manifold gauge center port hose from vacuum pump.
Attach the manifold center port hose to a dry nitrogen
cylinder with pressure regulator set to 150 psig (1034
kPa) and purge the hose. Open the manifold gauge
valves to break the vacuum in the line set and indoor
unit. Close the manifold gauge valves.

7. Shut 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.

8. Reconnect 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.

9. When 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.

10. Close manifold gauge valves and shut off the
HFC−410A cylinder and remove the manifold gauge
set.

Servicing Unit Delivered Void of Charge

If the system is void of refrigerant, clean the system using
the procedure described below.

1. Use nitrogen to pressurize the system and check for
leaks. Repair all leaks.

2. Evacuate the system to remove as much of the
moisture as possible.

3. Use nitrogen to break the vacuum and install a new
filter drier in the system.

4. Evacuate the system again. Then, weigh the
appropriate amount of HFC−410A refrigerant as listed
on unit nameplate into the system.

5. Monitor the system to determine the amount of
moisture remaining in the oil. It may be necessary to
replace the filter drier several times to achieve the
required dryness level. If system dryness is not

verified, the compressor will fail in the future.

Electrical Connections

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 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. Any excess high voltage field
wiring should be trimmed or secured away from the
low voltage field wiring.

2. Ground unit at unit disconnect switch or to an earth
ground.

NOTE − To facilitate conduit, a hole is in the bottom of the
control box. Connect conduit to the control box using a
proper conduit fitting.

NOTE − Units are approved for use only with copper
conductors.

NOTE − 24VAC, Class II circuit connections are made in
the low voltage junction box. See figure 30 for field wiring
diagram.

Page 15

XC15 SERIES

NOTE − A COMPLETE UNIT WIRING DIAGRAM IS
LOCATED INSIDE THE UNIT CONTROL BOX COVER.

Figure 30. Typical Wiring Diagram

NOTE − See unit wiring diagram for power supply
connections. If indoor unit is not equipped with blower
relay. It must be field−provided and installed (P−8−3251 or
equivalent)

NOTE − For proper voltages, select thermostat wire gauge
per the following chart:

Table 3. Wire Run Lengths

Wire run length AWG # Insulation type

less than 100’ (30m) 18

more than 100’ (30m) 16

color−coded, temperature
rating 35ºC minimum

3. 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, drafts or vibrations.

4. Install low voltage wiring from outdoor to indoor unit
and from thermostat to indoor unit as illustrated in
figure 30.

5. Do not bundle any excess 24V control wire inside
control box. Run control wire through installed wire tie
and tighten wire tie to provide low voltage strain relief
and to maintain separation of field installed low and
high voltage circuits.

Start−Up and Charging Procedures

3. After evacuation is complete, open the liquid line and
suction line service valves to release the refrigerant
charge (contained in outdoor unit) into the system.

4. Replace the stem caps and secure finger tight, then
tighten an additional one-sixth (1/6) of a turn.

5. Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit’s
nameplate. If not, do not start the equipment until you
have consulted the power company and the voltage
condition has been corrected.

6. Set the thermostat for a cooling demand. Turn on
power to the indoor blower and close the outdoor unit
disconnect switch to start the unit.

7. Recheck voltage while the unit is running. Power must
be within range shown on the nameplate.

8. Check system for sufficient refrigerate by using the
procedures listed under Testing and Charging System
on page 17.

SETTING UP TO CHECK CHARGE

1. Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of HFC−410A.

2. Connect the manifold gauge set to the unit’s service
ports as illustrated in figure 4.

D low pressure gauge to suction line service port.

D high pressure gauge to liquid line service port.

IMPORTANT

If unit is equipped with a crankcase heater, it should
be energized 24 hours before unit start−up to
prevent compressor damage as a result of slugging.

1. Rotate fan to check for binding.

2. Inspect all factory− and field−installed wiring for loose
connections.

506044−01 06/08

INDOOR COIL AIRFLOW CHECK

Check indoor coil airflow using the Delta−T (DT) process

as illustration in figure 31.

DETERMINING CHARGE METHOD

To determine the correct charging method, use the
illustration in figure 32.

Page 16

Temp.
of air
entering
indoor
coil ºF

A

Wet−bulb ºF

DRY

BULB

C

53º

80 24 24 24 23 23 22 22 22 20 19 18 17 16 15
78 23 23 23 22 22 21 21 20 19 18 17 16 15 14
76 22 22 22 21 21 20 19 19 18 17 16 15 14 13
74 21 21 21 20 19 19 18 17 16 16 15 14 13 12

Dry−bulb

72 20 20 19 18 17 17 16 15 15 14 13 12 11 10

70 19 19 18 18 17 17 16 15 15 14 13 12 11 10

57 58 59 60 61 62 63 64 65 66 67 68 69 70

T

Drop

19º

All temperatures are

expressed in ºF

Figure 31. Checking Indoor Airflow over Evaporator Coil using Delta−T Chart

DT

air flowair flow

INDOOR
COIL

1. Determine the desired DTMeasure entering air temperature
using dry bulb (A) and wet bulb (B). DT is the intersecting value of A
and B in the table (see triangle).

2. Find temperature drop across coilMeasure the coil’s dry bulb
entering and leaving air temperatures (A and C). Temperature Drop
Formula: (T

3. Determine if fan needs adjustmentIf the difference between the
measured T

B

A

72º

B

64º

WET

BULB

DRY

BULB

justment is needed. See examples: Assume DT = 15 and A temp. =
72º, these C temperatures would necessitate stated actions:

Cº T

Drop

53º 19 – 15 = 4 Increase the airflow
58º 14 – 15 = −1 (within +3º range) no change
62º 10 – 15 = −5 Decrease the airflow

4. Adjust the fan speedSee indoor unit instructions to in-

crease/decrease fan speed.

Changing air flow affects all temperatures; recheck temperatures to

confirm that the temperature drop and DT are within +3º.

) = A minus C.

Drop

and the desired DT (T

Drop

– DT = ºF ACTION

Drop

–DT) is within +3º, no ad-

START: Determine the correct charge method:

TXV

65ºF

(18.3ºC) and

Above

APPROACH OR

64ºF

(17.7ºC) and

Below

WEIGH-IN

SUBCOOLING

Figure 32. Determining Charge Method

START: Measure outdoor ambient temperature

USE EITHER APPROACH

OR SUBCOOLING

METHOD

ABOVE

WHEN TO CHARGE?

S Warm weather best
S Can charge in colder weather

CHARGE METHOD? Determine by:

S Outdoor ambient temperature

REQUIREMENTS:

S Sufficient heat load in structure
S Indoor temperature between 70-80ºF (21−26ºC)
S Manifold gauge set connected to unit
S Thermometers:

− to measure outdoor ambient temperature

− to measure liquid line temperature

− to measure suction line temperature

1. Check Liquid and suction line pressures

2. Compare unit pressures with Table 5,

BELOW

Above or

below 65ºF

(18ºC)?

Normal Operating Pressures.

3. Conduct leak check; evacuate as
previously outlined.

4. Weigh in the unit nameplate charge plus
any charge required for line set differences
over feet.

WEIGH IN

Refrigerant Charge per Line Set Length

Liquid Line

Set Diameter

3/8" (9.5 mm)

NOTE − *If line length is greater than 15 ft. (4.6 m), add this
amount. If line length is less than 15 ft. (4.6 m), subtract this
amount.

Ounces per 5 feet (g per 1.5 m)

adjust from 15 feet (4.6 m) line set*

3 ounce per 5’ (85 g per 1.5 m)

This nameplate is for illustration purposes
only. Go to actual nameplate on outdoor
unit for charge information.

Figure 33. Using Weigh In TXV Method

Page 17

XC15 SERIES

START: Measure outdoor ambient temperature

DO NOT CHARGE UNIT

USE WEIGH-IN METHOD

(Results of charging at low

Weigh-in or remove refriger-

temperatures not reliable)

ant based upon line length

If value is greater than shown (high
approach), add refrigerant; if less than
shown (liquid temp too close to ambient
temp, low approach), remove
refrigerant.

BELOW

Ambient 65ºF

If refrigerant added or removed,
retest to confirm that unit is
properly charged

APPº (Approach) Values(F:+/−1.0° [C: +/−0.6°])

Models

ºF (ºC)* −024 −030 −036 −042 −048 −060. . . . . .

Any 8 (4.4) 13 (7.2) 13 (7.2) 15 (8.3) 6 (3.3) 10 (5.6). .
*Temperature of air entering outdoor coil

Figure 34. Using Approach TXV Method

START: Measure outdoor ambient temperature

USE WEIGH-IN METHOD

DO NOT CHARGE UNIT

Weigh-in or remove refrigerant

(Results of charging at low

based upon line length

temperatures not reliable)

If refrigerant added or
removed, verify charge using
the approach method

If value is greater than shown,
remove refrigerant; if less than
shown, add refrigerant

BELOW

BLOCK OUTDOOR COIL: [sometimes necessary with
lower temperatures] Use cardboard or plastic sheet to
restrict the airflow through the outdoor coil to achieve
pressures from 325−375 psig (2240−2585 kPa). Higher
pressures are needed to check charge. Block equal
sections of air intake panels and move coverings sideways
until the liquid pressure is in the above noted ranges.

Ambient 65ºF

Outdoor

(18ºC)?

Outdoor

(18ºC)?

ABOVE

ABOVE

1. Confirm proper airflow across coil using figure

31.

2. Compare unit pressures with Table 5, Normal
Operating Pressures.

3. Use APPROACH to correctly charge unit or to
verify the charge is correct.

4. Set thermostat to call for heat (must have a
cooling load between 70-80ºF (21−26ºC).

5. Connect gauge set.

6. When heat demand is satisfied, set thermostat
to call for cooling.

7. Allow temperatures and pressures to stabilize.

8. Record outdoor ambient temperature:

AMBº =_________

9. Record line temp:

LIQº = __________

10. Subtract to determine approach (APPº):

LIQº_____ − AMBº _____ = APPº_____

11. Compare results with table to the left.

1. Confirm proper airflow across coil using figure

31.

2. Compare unit pressures with Table 5, Normal
Operating Pressures.

3. Use SUBCOOLING to correctly charge unit or to
verify the charge is correct.

4. Set thermostat to call for heat (must have a
cooling load between 70-80ºF (21−26ºC)

5. Connect gauge set

6. Measure outdoor ambient temperature

7. When heat demand is satisfied, set thermostat to
call for cooling

8. Allow temperatures and pressures to stabilize.

NOTE − If necessary, block outdoor coil to
maintain 325 − 375 psig.

9. Record liquid line temp:

LIQº = ______

10. Measure liquid line pressure and use the value to
determine saturation temperature (see table 4):

SATº = ______

11. Subtract to determine subcooling (SCº):

SATº_____ − LIQº _____ = SCº _____

12. Compare results with table to the left.

SCº (Subcooling) Values (F:+/−1.0° [C: +/−0.6°])

Models

ºF (ºC)* −024 −030 −036 −042 −048 −060. . . . . .

Any 7 (3.9.) 4 (2.2) 5 (2.8) 7 (3.9) 6 (3.3) 7 (3.9). . .
*Temperature of air entering outdoor coil

Figure 35. Using Subcooling TXV Method

506044−01 06/08

Page 18

Table 4. HFC−410A Temperature (°F) − Pressure (Psig)

°F Psig °F Psig °F Psig °F Psig °F Psig °F Psig °F Psig °F Psig

32 100.8 48 137.1 63 178.5 79 231.6 94 290.8 110 365.0
33 102.9 49 139.6 64 181.6 80 235.3 95 295.1 111 370.0 126 451.8 142 552.3
34 105.0 50 142.2 65 184.3 81 239.0 96 299.4 112 375.1 127 457.6 143 559.1
35 107.1 51 144.8 66 187.7 82 242.7 97 303.8 113 380.2 128 463.5 144 565.9
36 109.2 52 147.4 67 190.9 83 246.5 98 308.2 114 385.4 129 469.5 145 572.8
37 111.4 53 150.1 68 194.1 84 250.3 99 312.7 115 390.7 130 475.6 146 579.8
38 113.6 54 152.8 69 197.3 85 254.1 100 317.2 116 396.0 131 481.6 147 586.8
39 115.8 55 155.5 70 200.6 86 258.0 101 321.8 117 401.3 132 487.8 148 593.8
40 118.0 56 158.2 71 203.9 87 262.0 102 326.4 118 406.7 133 494.0 149 601.0
41 120.3 57 161.0 72 207.2 88 266.0 103 331.0 119 412.2 134 500.2 150 608.1
42 122.6 58 163.9 73 210.6 89 270.0 104 335.7 120 417.7 135 506.5 151 615.4
43 125.0 59 166.7 74 214.0 90 274.1 105 340.5 121 423.2 136 512.9 152 622.7
44 127.3 60 169.6 75 217.4 91 278.2 106 345.3 122 428.8 137 519.3 153 630.1
45 129.7 61 172.6 76 220.9 92 282.3 107 350.1 123 434.5 138 525.8 154 637.5
46 132.2 62 175.4 77 224.4 93 286.5 108 355.0 124 440.2 139 532.4 155 645.0

47 134.6 78 228.0 109 360.0 140 539.0

125 445.9

141 545.6

Table 5. Normal Operating Pressures (Liquid +10 and Suction +5 psig)

Use this table to perform maintenance checks; it is not a procedure for charg­ing the system. Minor variations in these pressures may be due to differences

IMPORTANT

in installations. Significant deviations could mean that the system is not prop­erly charged or that a problem exists with some component in the system.

Model −024 −030 −036 −042 −048 −060

°F (°C)** Liquid Suction Liquid Suction Liquid Suction Liquid Suction Liquid Suction Liquid Suction

65 (18.3) 238 139 246 138 251 133 261 144 224 129 242 131
70 (21.1) 256 139 265 139 270 134 281 145 241 130 262 132
75 (23.9) 275 140 287 140 291 134 303 146 259 131 282 134
80 (26.7) 296 141 307 141 312 134 326 147 279 133 303 135
85 (29.4) 319 142 330 142 335 136 350 148 301 134 326 136
90 (32.2) 342 142 354 143 359 137 376 149 323 135 349 137

95 (35.0) 366 143 379 144 384 138 402 150 347 137 372 138
100 (37.8) 392 144 404 144 411 140 430 151 372 138 397 140
105 (40.6) 418 146 432 145 438 141 459 152 397 140 422 141
110 (43.3) 448 146 461 147 468 143 490 153 422 141 448 143
115 (46.1) 480 147 491 148 501 144 525 154 449 143 475 146

* These are typical pressures only. Indoor match up, indoor air quality, and indoor load will cause the pressures to vary.
** Temperature of air entering outdoor coil.

INSTALLING SERVICE VALVE CAPS

Disconnect gauge set and re−install both the liquid and
suction service valve caps.

OUTDOOR UNIT

SERVICE VALVE

INSTALL CAPS

Figure 36. Installing Service Valve Port Caps

System Operation

The outdoor unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower switch
is in the ON position, the indoor blower operates
continuously.

HIGH PRESSURE SWITCH

XC15 units are equipped with a high-pressure switch that
is located in the liquid line of the compressor as illustrated

in Unit Dimensions on page 2.

The switch is a Single Pole, Single Throw (SPST),
manual−reset switch which is normally closed and
removes power from the compressor when discharge
pressure rises above factory setting at 590 + 10 psi. The
manual−reset switch can be identified by a red cap that is
press to reset the module.

LOW PRESSURE SWITCH

XC15 units are equipped with a low pressure switch that is
located in the suction line to the compressor as illustrated
in Unit Dimensions on page 2. The switch is a Single Pole,
Single Throw (SPST), auto−reset switch that is normal
closed. The switch opens at 40 psi and closes at 90 psi.

FILTER DRIER

A drier is factory−installed in each XC15 unit as illustrated
in Unit Dimensions on page 2. A replacement drier is
available from Lennox. Refer to Lennox Repair Part
Program.

Page 19

XC15 SERIES

Lennox System Operation Monitor
(LSOM) (100034−2)

The diagnostic indicator detects the most common fault
conditions in the air conditioning system. When an
abnormal condition is detected, the module communicates
the specific condition through its ALERT and TRIP lights.
The module is capable of detecting both mechanical and
electrical system problems.

RUN

COMMON

START

IMPORTANT

This monitor does not provide safety protection.
The is a monitoring device only and cannot control
or shut down other devices.

LSOMLED FUNCTIONS

The LSOM LED functions are described in the following
table. Refer to table 8 for the complete explanation of
troubleshooting codes.

Table 6. LED Functions

Label

Power Green

Alert Yellow

Trip Red

RESETTING ALERT CODES

Alert codes can be reset manually or automatically:

Manual Reset

Cycle the 24VAC power to LSOM off and on. After power
up, existing code will display for 60 seconds and then clear.
Manual reset can be achieve by any of the following
methods:

S Disconnecting R wire from the LSOM’s R terminal.

S Turning the indoor unit off an on again.

Automatic Reset

After an alert is detected, the LSOM continues to monitor
the compressor and system. When/if conditions return to
normal, the alert code is turned off automatically.

COMPRESSOR WIRE ROUTING

The scroll compressor’s run R, common C, and start S
wires are factory routed through the holes in the LSOM
marked R, C, and S as illustrated in figure 37. The common
C wire need not be routed through the module for it to
operate properly.

LED

Color

Function

Indicates voltage within the range of
19−28VAC is present at the system monitor
power connection.

Communicates an abnormal system
condition through a unique flash code. The
alert LED flashes a number of times
consecutively; then pauses; then repeats
the process. This consecutive flashing
correlates to a particular abnormal
condition.

Indicates there is a demand signal from the
thermostat but no current to the compressor
is detected by the module.

Figure 37. Compressor Wire Routing

(Factory Installed)

TERMINAL CONNECTIONS

This section address terminal connections and their
purpose.

Power (R and C Terminals)

LSOM requires a constant nominal 24VAC power supply.
The wiring to the module’s R and C terminals must be
directly from the indoor unit or thermostat. The module can
not be powered by the C terminal, defrost board or other
control board without experiencing nuisance alerts.

When constant 24VAC (R wire) is not present in the
outdoor unit, use one of the spare wires in the thermostat
cable to bring power to the module. Connect the other end
of the spare wire to R at the indoor unit or thermostat.

Thermostat Demand Wiring (Y Terminal)

LSOM requires a thermostat demand signal to operate
properly. The thermostat demand signal input terminal,
labeled Y on the module, should always be connected to
the compressor contactor coil so that when the coil is
energized, the demand signal input is 24VAC. When
thermostat demand is not present, Y should be less than

0.5VAC.

Alert Communication (L Terminal) (Optional)

The L terminal is used to communicate alert codes to the
room thermostat. On selected Lennox Comfort Sense,
Elite and Merit thermostats there is an L terminal for direct
input from the LSOM. See specific thermostat user guide
on how alerts are displayed.

Data Port Terminal

The data port terminal is for future use and has not been
implemented at this time.

INSTALLATION VERIFICATION

To verify correct LSOM installation, perform the two
following functional tests:

Function Test 1

1. Disconnect power from the compressor.

2. Force a thermostat call for cooling.

3. The red LED should turn on indicating a compressor

trip as long as 24VAC is measured at the Y terminal.
If the red LED does not function as described, refer to
table 7 to verify the wiring.

Function Test 2

1. Disconnect power from the compressor and 24VAC
power from LSOM.

2. Remove the wire from the Y terminal of LSOM and
reapply power to the compressor, allowing the

506044−01 06/08

Page 20

compressor to run. The yellow LED will begin flashing
a code 8 indicating a welded contactor.

3. Disconnect power from the compressor and 24VAC
power from the LSOM. While the LSOM is off, reattach
the wire to the Y terminal.

Table 7. LSOM Module LED Troubleshooting Codes

Status LED Condition

Mis−wired Module
Indication

4. Reapply power to the compressor and 24VAC power
to the LSOM; the yellow LED will flash the previous
code for 60 seconds and then turn off. If the yellow
LED does not function as described, refer to table 7 to
verify the wiring.

Status LED Troubleshooting Information

Green LED ON Module not powering up.

Green LED Intermittent

Red LED ON

Red and Yellow LED Simultaneous flashing.

Module powers up only when
compressor runs.

LED is on but system and
compressor check OK.

Table 8. LSOM System LED Troubleshooting Codes

Status LED
Condition

Red LED ON

Yellow Flash Code 1

Yellow Flash Code 2

Status LED Description Status LED Troubleshooting Information

Thermostat demand signal Y1 is
present, but compressor not
running

Long Run Time − Compressor is
running extremely long run
cycles.

System Pressure Trip −
Discharge or suction pressure
out of limits or compressor
overloaded

Determine/verify that both R and C module terminals are connected and
voltage is present at both terminals.

Determine if R and Y terminals are wired in reverse. Verify module’s R and C
terminals have a constant source.

1

Verify Y terminal is connected to 24VAC at contactor coil.

2

Verify voltage at contactor coil falls below 0.5VAC when off.

3

Verify 24VAC is present across Y and C when thermostat demand signal is
present; if not present, R and C wires are reversed.

Indicates that the control circuit voltage is too low for operation. Verify R and C
terminals are supplied with 19−28VAC.

1

Compressor protector is open.

S Check for high head pressure
S Check compressor supply voltage

2

Outdoor unit power disconnect is open.

3

Compressor circuit breaker or fuse(s) is open.

4

Broken wire or connector is not making contact.

5

Low or high pressure switch open if present in the system.

6

Compressor contactor has failed to close.

1

Low refrigerant charge.

2

Evaporator blower is not running.

S Check blower relay coil and contacts
S Check blower motor capacitor
S Check blower motor for failure or blockage
S Check evaporator blower wiring and connectors
S Check indoor blower control board
S Check thermostat wiring for open circuit

3

Evaporator coil is frozen.

S Check for low suction pressure
S Check for excessively low thermostat setting
S Check evaporator airflow (coil blockages or return air filter)
S Check ductwork or registers for blockage.

4

Faulty metering device.

S Check TXV bulb installation (size, location and contact)
S Check if TXV is stuck closed or defective

5

Condenser coil is dirty

6

Liquid line restriction (filter drier blocked if present)

7

Thermostat is malfunctioning

S Check thermostat sub−base or wiring for short circuit
S Check thermostat installation (location and level)

1

High head pressure.

S Check high pressure switch if present in system
S Check if system is overcharged with refrigerant
S Check for non−condensable in system

2

Condenser coil poor air circulation (dirty, blocked, damaged).

3

Condenser fan is not running.

S Check fan capacitor
S Check fan wiring and connectors
S Check fan motor for failure or blockage

4

Return air duct has substantial leakage.

.

.

.

Page 21

XC15 SERIES

Status LED
Condition

Yellow Flash Code 3

Yellow Flash Code 4 Locked Rotor

Yellow Flash Code 5 Open Circuit

Yellow Flash Code 6

Yellow Flash Code 7

Yellow Flash Code 8

Yellow Flash Code 9

Short Cycling − Compressor is

running only briefly

Open Start Circuit − Current
only in run circuit

Open Run Circuit − Current only
in start circuit

Welded Contactor −
Compressor always runs

Low Voltage − Control circuit
<17VAC

Status LED Troubleshooting InformationStatus LED Description

1

Thermostat demand signal is intermittent.

2

Time delay relay or control board is defective.

3

If high pressure switch is present, see Flash Code 2 information.

1

Run capacitor has failed.

2

Low line voltage (contact utility if voltage at disconnect is low).

S Check wiring connections

3

Excessive liquid refrigerant in the compressor.

4

Compressor bearings are seized.

1

Outdoor unit power disconnect is open.

2

Unit circuit breaker or fuse(s) is open.

3

Unit contactor has failed to close.

S Check compressor contactor wiring and connectors
S Check for compressor contactor failure (burned, pitted or open)
S Check wiring and connectors between supply and compressor
S Check for low pilot voltage at compressor contactor coil

4

High pressure switch is open and requires manual reset.

5

Open circuit in compressor supply wiring or connections.

6

Unusually long compressor protector reset time due to extreme ambient tempera­ture.

7

Compressor windings are damaged.

S Check compressor motor winding resistance

1

Run capacitor has failed.

2

Open circuit in compressor start wiring or connections.

S Check wiring and connectors between supply and the compressor S" terminal

3

Compressor start winding is damaged.

S Check compressor motor winding resistance

1

Open circuit in compressor start wiring or connections.

S Check wiring and connectors between supply and the compressor R" terminal

2

Compressor start winding is damaged.

S Check compressor motor winding resistance

1

Compressor contactor failed to open.

2

Thermostat demand signal not connected to module.

1

Control circuit transformer is overloaded.

2

Low line voltage (contact utility if voltage at disconnect is low).

S Check wiring connections

NOTE − Last code will display for 1 minute when power is cycled to module. Power must be on to module for a minimum of 1 minute for code to clear.

Maintenance

At the beginning of each cooling season, check the system
as follows:

NOTE − Outdoor fan motor is prelubricated and sealed. No
further lubrication is needed.

WARNING

Electric shock hazard. Can cause
injury or death. Before attempting to
perform any service or maintenance,
turn the electrical power to unit OFF at
disconnect switch(es). Unit may have
multiple power supplies.

1. Clean and inspect the outdoor coil. The coil may be
flushed with a water hose. Ensure the power is turned
off before you clean the coil.

2. Check connecting lines and coils for signs of oil leaks.

3. Check wiring for loose connections.

4. Check for correct voltage at unit (unit operating).

5. Check amp−draw outdoor fan motor:

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.

UNIT NAMEPLATE: _________ ACTUAL: __________

NOTE − If owner reports insufficient cooling, the unit should
be gauged and refrigerant charge checked.

INDOOR COIL

1. Clean coil, if necessary.

2. Check connecting lines and coils for signs of oil leaks.

3. Check condensate line and clean, if necessary.

Page 22

506044−01 06/08

INDOOR UNIT

1. Clean or change filters.

2. Adjust blower speed for cooling. Measure the pressure
drop over the coil to determine the correct blower CFM.
Refer to the unit information service manual for pressure
drop tables and procedure.

3. Check blower for accumulation of dirt or debris.

4. Check all wiring for loose connections

5. Check for correct voltage at unit (blower operating).

6. Check amp−draw on blower motor:

UNIT NAMEPLATE: _________ ACTUAL: __________

Sound Reduction (SR1) Cover

ASSEMBLY PROCEDURE

Figure 38 identifies the sound reduction parts. Assembly
procedures are as follows:

1. Put SR1 base on unit base pan.

2. Install compressor on base.

3. Cover SR1 base with wet rags to protect against any
brazing material.

4. Braze suction tube.

5. Braze discharge tube.

6. Cool connections to ambient temperature.

7. Perform leak check.

8. Install suction grommet.

9. Install SR1 left and right side covers.

10. Fasten 60" bottom cable tie.

11. Install discharge grommet.

12. Install top caps.

13. Fasten 36" top cable tie.

14. Fasten 36" middle cable tie.

TOP CABLE TIE

LEFT TOP CAP

MIDDLE CABLE

GROMMET

LEFT
SIDE
COVER

SUCTION

TIE

BASE

BOTTOM CABLE

TIE

COVER

Figure 38. Sound Reduction Cover Parts

RIGHT

SIDE

DISCHARGE
GROMMET

RIGHT TOP CAP

Homeowner Information

IMPORTANT

Turn off electrical power to the unit at the
disconnect switch before performing any
maintenance. The unit may have multiple power
supplies.

MAINTENANCE

In order to ensure peak performance, your system must be
properly maintained. Clogged filters and blocked airflow
prevent your unit from operating at its most efficient level.

1. Air FilterAsk your Lennox dealer to show you where

your indoor unit’s filter is located. It will be either at the
indoor unit (installed internal or external to the cabinet)
or behind a return air grille in the wall or ceiling. Check
the filter monthly and clean or replace it as needed.

2. Disposable FilterDisposable filters should be

replaced with a filter of the same type and size.

NOTE − If you are unsure about the filter required for your
system, call your Lennox dealer for assistance.

3. Reusable FilterMany indoor units are equipped

with reusable foam filters. Clean foam filters with a
mild soap and water solution; rinse thoroughly; allow
filter to dry completely before returning it to the unit or
grille.

NOTE − The filter and all access panels must be in place
any time the unit is in operation.

4. Electronic Air CleanerSome systems are

equipped with an electronic air cleaner, designed to
remove airborne particles from the air passing through
the cleaner. If your system is so equipped, ask your
dealer for maintenance instructions.

5. Indoor UnitThe indoor unit’s evaporator coil is

equipped with a drain pan to collect condensate
formed as your system removes humidity from the
inside air. Have your dealer show you the location of
the drain line and how to check for obstructions. (This
would also apply to an auxiliary drain, if installed.)

IMPORTANT

Sprinklers and soaker hoses should not be installed
where they could cause prolonged exposure to the
outdoor unit by treated water. Prolonged exposure
of the unit to treated water (i.e., sprinkler systems,
soakers, waste water, etc.) will corrode the surface
of steel and aluminum parts and diminish
performance and longevity of the unit.

6. Outdoor UnitMake sure no obstructions restrict

airflow to the outdoor unit. Leaves, trash or shrubs
crowding the unit cause the outdoor unit to work harder
and use more energy. Keep shrubbery trimmed away
from the unit and periodically check for debris which
collects around the unit. When removing debris from
around the unit, be aware of metal edges on parts and
screws. Although special care has been taken to keep
exposed edges to a minimum, physical contact with

Page 23

XC15 SERIES

metal edges and corners while applying excessive
force or rapid motion can result in personal injury.
Cleaning of the outdoor unit’s coil should be performed
by a trained service technician. Contact your dealer
and set up a schedule (preferably twice a year, but at
least once a year) to inspect and service your air
conditioning or heat pump system.

THERMOSTAT OPERATION

Thermostat operations vary from one thermostat to
another. The following provides general operation
procedures. Refer to the user’s information manual
provided with your thermostat for specific operation
details.

Temperature Setting Levers  Set the lever or dial to the
desired temperature setpoints for both heating and
cooling. Avoid frequent temperature adjustment; turning
the unit offthen back onbefore pressures can equalize
will put unusual stress on the unit’s compressor.

Fan Switch  In AUTO or INT (intermittent) mode, the
blower operates only when the thermostat calls for heating
or cooling. This mode is generally preferred when humidity
control is a priority. The ON or CONT mode provides
continuous indoor blower operation, regardless of whether
the compressor or furnace is operating. This mode is
required when constant air circulation or filtering is desired.

System Switch  Set the system switch for heating,

cooling or auto operation. The auto mode allows the
system to automatically switch from heating mode to
cooling mode to maintain predetermined comfort settings.

Temperature Indicator  The temperature indicator
displays the actual room temperature.

PROGRAMMABLE THERMOSTATS

Your Lennox system may be controlled by a
programmable thermostat. These thermostats provide the
added feature of programmable time-of-day set points for
both heating and cooling. Refer to the user’s information
manual provided with your thermostat for operation
details.

PRESERVICE CHECK

If your system fails to operate, check the following before
calling for service:

S Make sure all electrical disconnect switches are ON.
S Make sure the room thermostat temperature selector

AND the system switch are properly set.

S Replace any blown fuses, or reset circuit breakers.
S Make sure unit access panels are in place.
S Make sure air filter is clean.
S Locate and record unit model number before calling.

Optional Accessories

Refer to the Lennox XC15 Engineering Handbook for the
latest available optional accessories for this unit.

XC15 Start−Up and Performance Checklist

Customer Address

Indoor Unit Model Serial

Outdoor Unit Model Serial

Notes:

START UP CHECKS

Refrigerant Type:

Rated Load Amps Actual Amps Rated Volts Actual Volts

Condenser Fan Full Load Amps Actual Amps:

COOLING MODE

Suction Pressure: Liquid Pressure:

Supply Air Temperature: Ambient Temperature: Return Air: Temperature:

System Refrigerant Charge (Refer to manufacturer’s information on unit or installation instructions for required subcooling and approach
temperatures.)

Subcooling:

Saturated Condensing Temperature (A)

minus Liquid Line Temperature (B)

Approach:

Liquid Line Temperature (A)

minus Outdoor Air Temperature (B)

Indoor Coil Temperature Drop (18 to 22°F) A  B = COIL TEMP DROP

Return Air Temperature (A)

minus Supply Air Temperature (B)

A  B = SUBCOOLING

A  B = APPROACH

506044−01 06/08

Page 24