Lennox XC25-024-230-01, XC25-036-230-01, XC25-048-230-01, XC25-060-230-01 Installation And Service Procedure

INSTALLATION AND SERVICE

PROCEDURE

Service Literature

Dave Lennox Signature

Corp. 1253-L11

July 24, 2013

IMPORTANT

XC25 units have refrigerant piping requirements that are unique to
this unit. Size and install the refrigerant piping per table 2 (page 14)
to ensure proper unit operation.

IMPORTANT:

Before applying any power (main, solar or low voltage) to the
outdoor unit, confirm the iComfort Wi-Fi® thermostat has

software Version 2.1 or higher installed. (Reference the iComfort
Wi-Fi® thermostat manual.)

This unit is an integral component of a system that requires an
iComfort Wi-Fi
or furnace.

®

thermostat and iComfort™-enabled air handler

®

Collection XC25 Series Units

TABLE OF CONTENTS

I. OVERVIEW

Model Number Identification 2....................

Typical Serial Number Identification 2..............

Specifications 2.................................

Electrical Data 3................................

Unit Dimensions 4..............................

Typical Unit Parts Arrangement 5.................

Operating Service Valves 7.......................

General 7.....................................

II. INSTALLATION

Unit Placement 9...............................

Removing and Installing Panels 12.................

New or Replacement Line Set 13..................

Brazing Connections 16...........................

Flushing the System 19...........................

Leak Testing the System 21.......................

Evacuating the System 21.........................

Electrical 24.....................................

Servicing Unit Delivered Void of Charge 29..........

Unit Start-Up 29.................................

XC25

®

XC25

iComfort Wi-Fi

iComfort™-enabled

air handler or

furnace

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.

WARNING

Electrical Hazard

High Voltage

Wait 5 Minutes

Electrical components may hold charge. Do
not remove this panel or service this area for
5 minutes after the power has been removed.

III. SYSTEM OPERATION AND SERVICE

7-Segment Alert and System Status Codes 30.......

Outdoor Control Push-Button Operation 35..........

Configuring Unit 39...............................

Reconfiguring Outdoor Control using iComfort Wi-Fi

Thermostat 40...................................

System Overview 40.............................

Maintenance 41..................................

SunSource

Unit Wiring Diagrams 42..........................

Factory Wiring Diagrams 45.......................

Unit Sequence of Operations 47...................

Component Testing 50............................

System Refrigerant 69............................

®

Home Energy System 41..............

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.

1

2013 Lennox Industries Inc.

®

Model Number identification

I. OVERVIEW

− −

C 25 XXX

X

230

-02

Refrigerant Type

X = R-410A

Unit Type

C = AIR CONDITIONER

Nominal Cooling Capacity

Minor Revision Number

Voltage

230 = 208/230V-1ph-60hz

024 = 2 tons

Series

036 = 3 tons
048 = 4 tons
060 = 5 tons

Typical Serial Number Identification

Location Code

19 = Saltillo, Mexico

58 = Marshalltown, IA

Year Code

08 = 2008
09 = 2009
10 = 2010

8 09 C

5

05716

5 (or 6) Digit Unique Number

Month Code

A = January
B = February
C = March

Specifications

Unit Outdoor Fan

Model Number

XC25-024-230-01 70 59 13 lbs, 10 oz 5 26

Sound Rating Number (dB)
Maximum Minimum

1

Factory Refrigerant

Charge

2

Number of Blades Diameter - inches.

Unit Outdoor Fan

Model Number

XC25-036-230-01 73 59 10 lbs, 12 oz 5 26

Model Number

XC25-048-230-01 74 66 14 lbs, 9 oz 5 26

Model Number

XC25-060-230-01 74 64 14 lbs, 8 oz 5 26

1

Tested according to AHRI Standard 270-2008 test conditions.

2

Factory refrigerant charge is sufficient for refrigerant line lengths up to 15 feet.

Sound Rating Number (dB)
Maximum Minimum

Sound Rating Number (dB)
Maximum Minimum

Sound Rating Number (dB)
Maximum Minimum

1

Unit Outdoor Fan

1

Unit Outdoor Fan

1

Factory Refrigerant

Factory Refrigerant

Factory Refrigerant

Charge

Charge

Charge

2

2

2

Number of Blades Diameter - inches.

Number of Blades Diameter - inches.

Number of Blades Diameter - inches.

XC25

2

Electrical Data

208/230V-60 Hz-1 Ph

Unit Compressor Outdoor Fan (RPM varies with compressor RPM)

Model Number

Maximum

Over-

current

Protection

(amps)

1

Minimum

Circuity

Ampacity

XC25-024-230-01 25 14.9 10.30 18.0 1/3 3020 1950 500 350 80 32 2.0

Unit Compressor Outdoor Fan (RPM varies with compressor RPM)

Model Number

Maximum

Over-

current

Protection

(amps)

1

Minimum

Circuity

Ampacity

XC25-036-230-01 30 19.5 14.00 18.0 1/3 4100 1950 650 350 157 32 2.0

Unit Compressor Outdoor Fan (RPM varies with compressor RPM)

Model Number

Maximum

Over-

current

Protection

(amps)

1

Minimum

Circuity

Ampacity

XC25-048-230-01 50 32.9 24.70 29.0 1/3 4220 3020 675 500 185 82 2.0

Unit Compressor Outdoor Fan (RPM varies with compressor RPM)

Model Number

Maximum

Over-

current

Protection

(amps)

1

Minimum

Circuity

Ampacity

XC25-060-230-01 50 34.1 25.70 29.0 1/3 4385 3020 700 500 212 82 2.0

1

HACR type circuit breaker or fuse.

2

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.

Rated

Load

Amps

2

(RLA)

Locked

Rotor
Amps
(LRA)

Motor

HP

CFM RPM WATTS

MAX MIN MAX MIN MAX MIN

Load
Amps
(FLA)

208/230V-60 Hz-1 Ph

Rated

Load

Amps

2

(RLA)

Locked

Rotor
Amps
(LRA)

Motor

HP

CFM RPM WATTS

MAX MIN MAX MIN MAX MIN

Load
Amps
(FLA)

208/230V-60 Hz-1 Ph

Rated

Load

Amps

2

(RLA)

Locked

Rotor
Amps
(LRA)

Motor

HP

CFM RPM WATTS

MAX MIN MAX MIN MAX MIN

Load
Amps
(FLA)

208/230V-60 Hz-1 Ph

Rated

Load

Amps

2

(RLA)

Locked

Rotor
Amps
(LRA)

Motor

HP

CFM RPM WATTS

MAX MIN MAX MIN MAX MIN

Load
Amps
(FLA)

Full

Full

Full

Full

XC25

3

Unit Dimensions -- Inches (mm)

UNIT SUPPORT

FEET

IMPORTANT

This unit must be matched with an indoor coil as
specified in Lennox Product Specification bulletin.
Coils previously charged with HCFC-22 must be
flushed.

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 nearby these areas during installation or while
servicing this equipment.

16-7/8

(429)

8-3/4
(222)

3-1/8

(79)

30-3/4

(781)

26-7/8

(683)

3-3/4 (95)

4-5/8
(117)

BASE WITH ELONGATED LEGS

WARNING

Electric Shock Hazard. Can cause injury or death. Unit
must be grounded in accordance with national and local
codes.
Line voltage is present at all components when unit is not
in operation on units with single‐pole contactors.
Disconnect all remote electric power supplies before
opening access panel. Unit may have multiple power
supplies.

XC25

4

Typical Unit Parts Arrangement

GROUND LUGS

CONTROL PANEL FOR

XC25-024 AND -036

CONTACTOR-SPST

(25FLA/35RES)

INVERTER REACTOR,

GROUND LUGS

230V, 4KW

OUTDOOR

CONTROL

CONTROL PANEL FOR

XC25-048 AND -060

DC INVERTER

CONTROL

INVERTER NOISE FILTER FOR

6KW INVERTER (208/240V,

60HZ, CURRENT RANGE 30A

MAXIMUM, INDUCTANCE

4.3MH)

CONTACTOR-SPST

(35FLA/40RES)

OUTDOOR CONTROL

Figure 1. Control Panel Components

5

INVERTER REACTOR,

230V, 6KW

DC INVERTER
CONTROL

XC25

VAPOR VALVE

AND GAUGE

PORT

LIQUID VALVE AND

GAUGE PORT

COMPRESSOR TOP CAP

SWITCH (THERMAL)

Typical Plumbing Components

VARIABLE-CAPACITY
COMPRESSOR - HFC-410A,
3-PHASE

LIQUID LINE SENSOR

LIQUID LINE BI-FLOW

FILTER DRIER

(HFC-410A)

LOW PRESSURE SWITCH - NORMALLY OPEN, SWITCH CLOSES
WHEN SYSTEM PRESSURES GO ABOVE 90±5, AND OPENS

WHEN SYSTEM PRESSURES DROP BELOW 40±5 PSIG

Figure 2. Plumbing (Component Locations and Specifications)

IMPORTANT

This unit must be matched with an indoor coil as
specified in Lennox Product Specification bulletin.
Coils previously charged with HCFC-22 must be
flushed.

CRANKCASE HEATER THERMOSTAT
(S40) OPENS AT 70ºF, CLOSES AT 50ºF

HIGH PRESSURE SWITCH - NORMALLY CLOSED. SWITCH OPENS
WHEN SYSTEM PRESSURES REACH 590±
SYSTEM PRESSURES DROP BELOW 418±15 PSIG

15, AND CLOSES WHEN

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 nearby these areas during installation or while
servicing this equipment.

XC25

6

WARNING

Electric Shock Hazard. Can cause injury
or death. Unit must be grounded in
accordance with national and local
codes.

Line voltage is present at all components
when unit is not in operation on units with
single‐pole contactors. Disconnect all
remote electric power supplies before
opening access panel. Unit may have
multiple power supplies.

General

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

The XC25 is a high-efficiency residential split-system air
conditioner, which features a variable-capacity scroll com
pressor and uses HFC-410A refrigerant. Units are
available in 2, 3, 4 and 5-ton sizes. The series is designed
for use with an expansion valve (approved for use with
HFC-410A) in the indoor unit only.

USING MANIFOLD GAUGE SET

When checking the system charge, only use a manifold
gauge set that features low loss anti-blow back fittings.

Manifold gauge set used with HFC-410A refrigerant sys
tems must be capable of handling higher system operating
pressures. The gauges should be rated for use with pres
sures of 0 - 800 psig on the high side and a low side of 30”
vacuum to 250 psig, with dampened speed to 500 psi.
Gauge hoses must be rated for use at or up to 800 psig of
pressure with a 4000 psig burst rating.

Table 1. Torque Requirements

Parts Recommended Torque

Service valve cap 8 ft.- lb. 11 NM

Sheet metal screws 16 in.- lb. 2 NM

Machine screws #10 28 in.- lb. 3 NM

Compressor bolts 90 in.- lb. 10 NM

Gauge port seal cap 8 ft.- lb. 11 NM

TORQUE REQUIREMENTS

When servicing or repairing HVAC components, ensure
the fasteners are appropriately tightened. Table 1 lists
torque values for fasteners.

Operating Service Valves

The liquid and vapor line service valves are used for re
moving refrigerant, flushing, leak testing, evacuating,
checking charge and charging.

Each valve is equipped with a service port which has a fac
tory-installed valve stem. Figure 3 provides information on
how to access and operating both angle and ball service
valves.

IMPORTANT

Only use hex 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 a
hex wrench rated at less than 50Rc risks rounding or
breaking off the wrench, or stripping the valve stem
recess.

See the Lennox Service and Application Notes #C-08-1
for further details and information.

WARNING

The State of California has determined that this product
may contain or produce a chemical or chemicals, in very
low doses, which may cause serious illness or death. It
may also cause cancer, birth defects, or reproductive
harm.

IMPORTANT

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

XC25

7

SERVICE VALVES

ANGLE AND BALL

Operating Angle–Type Service Valve:

1. Remove stem cap with an appropriately sized wrench.

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

SERVICE PORT CAP

SERVICE PORT CORE

(VALVE STEM SHOWN
CLOSED) INSERT HEX
WRENCH HERE

TO INDOOR

UNIT

(VALVE STEM SHOWN OPEN)
INSERT HEX WRENCH HERE

STEM CAP

TO OUTDOOR UNIT

ANGLE-TYPE SERVICE VALVE

(BACK-SEATED OPENED)

When service valve is OPEN, the service port is
open to line set, indoor and outdoor unit.

Operating Ball Type Service Valve:

1. Remove stem cap with an appropriately sized wrench.

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

TO INDOOR UNIT

TO OPEN ROTATE STEM
COUNTERCLOCKWISE 90°.

TO CLOSE ROTATE STEM
CLOCKWISE 90°.

SERVICE PORT

SERVICE PORT

SERVICE PORT

CORE

CAP

TO OUTDOOR

UNIT

BALL (SHOWN
CLOSED)

VALV E
STEM

STEM CAP

ANGLE-TYPE SERVICE VALVE

(FRONT-SEATED CLOSED)

When service valve is CLOSED, the service port is open
to the line set and indoor unit.

To Access Service Port:

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

1. Remove service port cap with an appropriately sized wrench.

2. Connect gauge set to service port.

3. When testing is completed, replace service port cap and tighten as
follows:

D With torque wrench: Finger tighten and

torque cap per table 1.

D Without torque wrench: Finger tighten and

use an appropriately sized wrench to turn
an additional 1/6 turn clockwise.

10

9

8

Reinstall Stem Cap:

Stem cap protects the valve stem from damage and serves as the
primary seal. Replace the stem cap and tighten as follows:

D With Torque Wrench: Finger tighten and then

torque cap per table 1.

D Without Torque Wrench: Finger tighten and

use an appropriately sized wrench to turn an
additional 1/12 turn clockwise.

10

9

8

11

11

7

7

12

6

12

6

1/6 TURN

1

2

3

4

5

1/12 TURN

1

2

4

5

3

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

Figure 3. Angle and Ball-Type Service Valves

XC25

8

II. INSTALLATION

Unit Placement

CAUTION

In order to avoid injury, take proper precaution when lift
ing heavy objects.

See Unit Dimensions on page 4 for sizing mounting slab,
platforms or supports. Refer to figure 4 for mandatory
installation clearance requirements.

POSITIONING CONSIDERATIONS

Consider the following when positioning the unit:

D Some localities are adopting sound ordinances based

on the unit sound level registered from the adjacent
property, not from the installation property. Install the
unit as far as possible from the property line.

D When possible, do not install the unit directly outside

a window. Glass has a very high level of sound trans
mission. For proper placement of unit in relation to a
window see figure 5, detail A.

PLACING UNIT ON SLAB

When installing unit at grade level, the top of the slab
should be high enough above grade so that water from
higher ground will not collect around the unit. The slab
should have a slope tolerance as described in figure 5, de
tail B.

NOTE - If necessary for stability, anchor unit to slab as de
scribed in figure 5, detail D.

ELEVATING THE UNIT

Units are outfitted with elongated support feet as illustrated
in figure 5, detail C.

If additional elevation is necessary, raise the unit by ex
tending the height of the unit support feet. Use a 2-inch
(50.8mm) Schedule 40 female threaded adapter to raise
the height of the unit.

The specified coupling will fit snugly into the recessed por
tion of the feet. Use additional 2-inch (50.8mm) Schedule
40 male threaded adaptors which can be threaded into the
female threaded adaptors to make additional adjustments
to the level of the unit.

NOTE - Keep the height of extenders short enough to en
sure a sturdy installation. If it is necessary to extend the
height further than what is stable, consider a different type
of field-fabricated framework that is sturdy enough for
greater heights.

CLEARANCE ON ALL SIDES — INCHES (MILLIMETERS)

6 (152)

12 (305)

36 (914)

ACCESS PANEL

CONTROL PANEL

ACCESS

LOCATION

30 (762)

LINE SET
CONNECTIONS

NOTES:

D CLEARANCE TO ONE OF THE THREE

SIDES MUST BE 36 INCHES (914MM).

D CLEARANCE TO ONE OF THE

REMAINING TWO SIDES MAY BE 12
INCHES (305MM) AND THE FINAL
SIDE MAY BE 6 INCHES (152MM).

NOTE - Dimensions are not to scale.

MINIMUM CLEARANCE BETWEEN

TWO UNITS

24 (610)

ACCESS PANEL

LINE SET

CONNECTIONS

MINIMUM CLEARANCE

ABOVE UNIT

48 (1219)

REAR VIEW OF UNIT

Figure 4. Installation Clearances

XC25

9

STABILIZING UNIT ON UNEVEN SURFACES

IMPORTANT

Unit Stabilizer Bracket Use (field-provided):

Always use stabilizers when unit is raised above the
factory height. (Elevated units could become unstable in
gusty wind conditions.)

Stabilizers may be used on factory height units when
mounted on unstable an uneven surface.

1. Remove the louvered panel from each side to expose
the unit base.

2. Install the brackets as illustrated in figure 5, detail D us
ing conventional practices.

3. Replace the panels after installation is complete.

ROOF MOUNTING

Locate the unit above a load-bearing wall or area of the roof
that can adequately support the unit. Consult local codes
for rooftop applications.

NOTICE

Roof Damage!
This system contains both refrigerant and oil. Some

rubber roofing material may absorb oil and cause the
rubber to swell when it comes into contact with oil. The
rubber will then bubble and could cause leaks. Protect
the roof surface to avoid exposure to refrigerant and oil
during service and installation. Failure to follow this
notice could result in damage to roof surface.

XC25

10

DETAIL A DETAIL B

INSTALL UNIT AWAY FROM WINDOWS

TWO 90° ELBOWS INSTALLED IN LINE SET

REDUCES LINE SET VIBRATION.

Outside Unit Placement

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.

GROUND LEVEL

Slab Mounting at Ground Level

BUILDING

STRUCTURE

MOUNTING
SLAB

DETAIL C

BASE

LEG DETAIL

2” (50.8MM) SCH 40

FEMALE THREADED

USE ADDITIONAL 2” SCH 40 MALE THREADED ADAPT
ERS WHICH CAN BE THREADED INTO THE FEMALE
THREADED ADAPTERS TO MAKE ADDITIONAL AD
JUSTMENTS TO THE LEVEL OF THE UNIT.

Elevated Slab Mounting using Feet

ADAPTER

2” (50.8MM) SCH 40

MALE THREADED

ADAPTER

Extenders

DETAIL D

Slab Side Mounting

#10 1/2” LONG SELF-DRILLING

SHEET METAL SCREWS

STABILIZING BRACKET (18 GAUGE

METAL — 2” WIDTH; HEIGHT AS

#10 1-1/4” LONG HEX HEAD

SCREW AND FLAT WASHER

CONCRETE SLAB — USE TWO PLASTIC
ANCHORS (HOLE DRILL 1/4”)

WOOD OR PLASTIC SLAB — NO PLASTIC ANCHOR
(HOLE DRILL 1/8”)

REQUIRED)

CORNER POST

MINIMUM ONE

Deck Top Mounting

STABILIZING BRACKET (18 GAUGE METAL
— 2” (50.8MM) WIDTH; HEIGHT AS
REQUIRED); BEND TO FORM RIGHT ANGLE

SAME FASTENERS AS
SLAB SIDE MOUNTING.

ONE BRACKET PER SIDE (MIN.); FOR EXTRA STABILITY, TWO
BRACKETS PER SIDE, 2” (50.8MM) FROM EACH CORNER.

PER SIDE

FOR EXTRA

STABILITY

Stabilizing Unit on Uneven Surfaces

IMPORTANT - To help stabilize an outdoor unit, some installations may require strap

ping the unit to the pad using brackets and anchors commonly available in the
marketplace.

COIL

BASE PAN

Figure 5. Placement and Slab Mounting

XC25

11

Removing and Installing Panels

ACCESS PANEL REMOVAL

PANELS

ACCESS AND LOUVERED

REMOVE AND INSTALL THE ACCESS PANEL
AS ILLUSTRATED.

WARNING

To prevent personal injury, or damage to panels, unit or structure, be
sure to observe the following:

While installing or servicing this unit, carefully stow all removed
panels out of the way, so that the panels will not cause injury to
personnel, nor cause damage to objects or structures nearby, nor will
the panels be subjected to damage (e.g., being bent or scratched).

While handling or stowing the panels, consider any weather
conditions, especially windy conditions, that may cause panels to be
blown around and battered.

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

LOUVERED PANEL REMOVAL

Remove the louvered panels as follows:

1. REMOVE TWO SCREWS, ALLOWING THE PANEL TO SWING OPEN SLIGHTLY.

2. HOLD THE PANEL FIRMLY THROUGHOUT THIS PROCEDURE ROTATE BOTTOM
CORNER OF PANEL AWAY FROM HINGED CORNER POST UNTIL LOWER THREE TABS
CLEAR THE SLOTS AS ILLUSTRATED IN DETAIL B.

3. MOVE PANEL DOWN UNTIL LIP OF UPPER TAB CLEARS THE TOP SLOT IN CORNER
POST AS ILLUSTRATED IN DETAIL A.

LOUVERED PANEL INSTALLATION

Position the panel almost parallel with the unit as illustrated in detail D with the screw side
as close to the unit as possible. Then, in a continuous motion:

1. SLIGHTLY ROTATE AND GUIDE THE LIP OF TOP TAB INWARD AS ILLUSTRATED IN DETAIL
A AND C; THEN UPWARD INTO THE TOP SLOT OF THE HINGE CORNER POST.

2. ROTATE PANEL TO VERTICAL TO FULLY ENGAGE ALL TABS.

3. HOLDING THE PANEL'S HINGED SIDE FIRMLY IN PLACE, CLOSE THE RIGHT-HAND SIDE
OF THE PANEL, ALIGNING THE SCREW HOLES.

4. WHEN PANEL IS CORRECTLY POSITIONED AND ALIGNED, INSERT THE SCREWS AND
TIGHTEN.

LIP

SCREW

HOLES

Detail B

Detail A

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

ALIGN PANEL WITH SCREW
HOLES. INSTALL SCREWS
AND TIGHTEN.

Detail C

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

Figure 6. Removing and Installing Panels

XC25

ANGLE MAY BE TOO EXTREME

PREFERRED ANGLE FOR INSTALLATION

Detail D

12

ROTATE IN THIS DIRECTION; THEN

DOWN TO REMOVE PANEL

HOLD DOOR FIRMLY ALONG

THE HINGED SIDE TO MAINTAIN

FULLY-ENGAGED TABS

New or Replacement Line Set

REFRIGERANT LINE SET

This section provides information on installation or replace

ment of existing line set. If new or replacement line set is

not being installed then proceed to Brazing Connections on

page 16.

IMPORTANT

Lennox highly recommends changing line set when
converting the existing system from HCFC-22 to
HFC-410A If that is not possible and the line set is the
proper size as referenced in table 2, use the procedure
outlined under Flushing the System on page 19.

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.

See figure 7 for recommended installation practices. Also,

consider the following when placing and installing a high-

efficiency outdoor unit.

Liquid lines that meter the refrigerant, such as RFC1 liquid

lines, must not be used in this application. Existing line set

of proper size may be reused. If system was previously

charged with HCFC-22 refrigerant, then existing line set

must be flushed (see Flushing the System on page 19).

IMPORTANT

Mineral oils are not compatible with HFC-410A. If oil

must be added, it must be a Polyol ester oil.

IMPORTANT !

If this unit is being matched with an approved line set
or indoor unit coil that 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 system
performance and capacity.

Failure to properly flush the system per the XC25
Installation and Service Procedures will void the
warranty.

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 inju
ry or death.

Never use oxygen to pressurize or
purge refrigeration lines. Oxygen,
when exposed to a spark or open
flame, can cause fire and/or an ex
plosion, that could result in property
damage, personal injury or death.

WARNING

When using a high pressure gas such
as 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).

Recommended POE oils are Mobil EAL ARCTIC 22 CC or

ICI EMKARATEt RL32CF.

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.

IMPORTANT !

Some scroll compressors have an internal vacuum
protector that will unload scrolls when suction pres
sure goes below 20 psig. A hissing sound will be
heard when the compressor is running unloaded.
Protector will reset when low pressure in system is
raised above 40 psig. DO NOT REPLACE COMPRES
SOR.

The XC25 is a variable-capacity cooling system utilizing
variable-speed compressor technology. With the variable­speed compressor and variable pumping capacity,
additional consideration must be given to refrigerant piping
sizing and application. The following guidelines are to be
used exclusively for the XC25 systems.

XC25

13

COOLING SYSTEM (HFC410A)

D Total equivalent length equals 180 feet (all piping and

fittings included).

NOTE - This is a general guide. Lengths may be more or
less, depending on remaining system design factors.

D Maximum linear (actual) length = 150 feet.
D Maximum linear liquid lift = 60 feet.

NOTE - Maximum lifts are dependent on total length, num
ber of elbows, and other factors that contribute to total
pressure drop.

D Maximum linear length of vapor riser = 60 feet.
D Size vertical vapor riser per table 3.
D Line set lengths up to 50 linear feet: Use rated line

sizes listed in table 2.

D Line set lengths between 51 and 150 linear feet:

Crankcase heater and nonbleed port TXV factory-in

stalled. No additional components required. Vertical
vapor riser must be sized to the vapor riser listed in
table 3 on systems with line sets longer than 51 feet.
Use tables 3 and 4 to determine the correct liquid and
vapor line sizes.

D Line set lengths over 150 linear feet: Not recom

mended.

D Additional oil is not required for systems with line

lengths up to 150 feet.

NOTE - Recommended POE oils are Mobil EAL ARCTIC
22 CC or ICI EMKARATEt RL32CF.

SUCTION TRAPS

In systems with the outdoor unit 5 to 60 feet above the in
door unit, one trap must be installed at the bottom of the
suction riser.

Table 2. Standard Refrigerant Line Set — Up to 50 Linear Feet

Inches (mm)

Model Number (-xx*) Valve Size Connections Recommended Line Sets

Model Number (-xx*)

XC25-024-230-XX
XC25-036-230-XX
XC25-048-230-XX

XC25-060-230-XX 3/8” (10 mm) 1-1/8” (29 mm) ** Field-fabricated

* Applicable to all minor revision numbers unless otherwise specified.
** Some applications may require a field-provided 1-1/8” to 7/8” adapter.

Liquid Line Suction Line

3/8” (10 mm) 7/8” (22 mm)

L15 Line Set
Model

L15-65-30 30 feet (9.1 m) 89J60
L15-65-40 40 feet (12.2 m) 89J61
L15-65-50 50 feet (15.2 m) 89J62

Line Set Length Catalog Number

Table 3. XC25 Piping Guidelines

Model

024 180 150 60 60 7/8” 5/8”

036 180 150 60 60 7/8” 3/4”

048 180 150 60 60 7/8” 7/8”

060 180 150 60 60 7/8” 7/8”

Maximum Total

Equivalent Length (ft)

Maximum Linear

(actual) Length (ft)

Maximum Vapor

Riser (ft)

Maximum

Linear Liquid

Lift (ft)

Preferred Vapor Line

Sizes for Horizontal

Runs

Required Vapor

Riser Size

Table 4. Liquid Line Diameter Selection Table

Total Linear Length (feet)

Unit

024

036

048

060

Line Size

5/16” 25 50 55 48 40 33

3/8” 25 50 60 60 60 60

3/8” 25 50 60 56 51 45

1/2” 25 50 60 60 60 60

3/8” 25 50 50 41 31 22

1/2” 25 50 60 60 60 60

3/8” 25 50 36 22 8 NR

1/2”

25 50 75 100 125 150

25

50 60 60 60 59

Note  Shaded rows indicate rated liquid line size.

1. Find your unit on the left side of the table.

2. Start with the rated liquid line size (shaded row) for the outdoor unit.

3. Select the actual total linear length of your system shown at the top of the table.

4. The elevation listed in the table is the maximum allowed for the liquid line listed.

5. Consider the larger liquid line size shown in the table if the elevation does not meet your requirements.

Max. Elevation

(ft)

XC25

14

LINE SET

INSTALLATION

LINE SET ISOLATION — THE FOLLOWING ILLUSTRATIONS ARE EXAM

PLES OF PROPER REFRIGERANT LINE SET ISOLATION:

REFRIGERANT LINE SET — TRANSITION

FROM VERTICAL TO HORIZONTAL

ANCHORED HEAVY NYLON
WIRE TIE OR AUTOMOTIVE

MUFFLER‐TYPE HANGER

AUTOMOTIVE

MUFFLER‐TYPE HANGER

IMPORTANT - Refrigerant lines must not contact structure.

REFRIGERANT LINE SET — INSTALLING

VERTICAL RUNS (NEW CONSTRUCTION SHOWN)

NOTE - INSULATE LIQUID LINE WHEN IT IS ROUTED THROUGH AREAS
WHERE THE SURROUNDING AMBIENT TEMPERATURE COULD BECOME
HIGHER THAN THE TEMPERATURE OF THE LIQUID LINE OR WHEN
PRESSURE DROP IS EQUAL TO OR GREATER THAN 20 PSIG.

IMPORTANT - Refrigerant lines must not contact
wall

OUTSIDE WALL

VAPOR LINE

LIQUID LINE

WALL
STUD

STRAP LIQUID LINE TO
VAPOR LINE

LIQUID LINE

NON-CORROSIVE

METAL SLEEVE

VAPOR LINE - WRAPPED
IN ARMAFLEX

REFRIGERANT LINE SET — INSTALLING

HORIZONTAL RUNS

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

WIRE TIE (AROUND
VAPOR LINE ONLY)

8 FEET (2.43 METERS)

STRAPPING

MATERIAL (AROUND

VAPOR LINE ONLY)

TAPE OR
WIRE TIE

FLOOR JOIST OR

ROOF RAFTER

8 FEET (2.43 METERS)

NON-CORROSIVE
METAL SLEEVE

STRAP THE VAPOR LINE TO THE
JOIST OR RAFTER AT 8 FEET (2.43
METERS) INTERVALS THEN STRAP
THE LIQUID LINE TO THE VAPOR LINE.

TAPE OR
WIRE TIE

WIRE TIE

INSIDE WALL

WOOD BLOCK

BETWEEN

STUDS

SLEEVE

VAPOR LINE WRAPPED

WITH ARMAFLEX

OUTSIDE

WALL

PVC

PIPE

FIBERGLASS

INSULATION

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

CAULK

STRAP

NON-CORROSIVE
METAL SLEEVE

WIRE TIE

WOOD BLOCK

WIRE TIE

STRAP

LIQUID
LINE

FLOOR JOIST OR

ROOF RAFTER

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.

Figure 7. Line Set Installation

XC25

15

Brazing Connections

Use the procedures outlined in figures 8 and 9 for brazing
line set connections to service valves.

WARNING

IMPORTANT

Allow braze joint to cool before removing the wet rag
from the service valve. Temperatures above 250ºF can
damage valve seals.

Danger of fire. Bleeding the refrigerant
charge from only the high side may result
in pressurization of the low side shell and
suction tubing. Application of a brazing
torch to a pressurized system may result
in ignition of the refrigerant and oil mixture

- Check the high and low pressures
before applying heat.

CAUTION

Brazing alloys and flux contain materials which are
hazardous to your health.

Avoid breathing vapors or fumes from brazing
operations. Perform operations only in well-ventilated
areas.

Wear gloves and protective goggles or face shield to
protect against burns.

Wash hands with soap and water after handling brazing
alloys and flux.

WARNING

Fire, Explosion and Personal Safety
Hazard.

Failure to follow this warning could re
sult 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 a fire and/or an explosion, that
could result in property damage, per
sonal injury or death.

XC25

16

PIPING PANEL REMOVAL AND LINE SET
PREPARATION

1

Remove piping panel for easier access to service valves. Cut ends
of the refrigerant lines square (free from nicks or dents) and debur
the ends. The pipe must remain round. Do not crimp end of the line.

CUT AND DEBUR

LINE SET SIZE MATCHES

SERVICE VALVE CONNECTION

SERVICE VALVE

COPPER TUBE

REDUCER

STUB

CONNECTION

LINE SET SIZE IS SMALLER

THAN CONNECTION

CAP AND CORE REMOVAL

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

2

service ports.

SERVICE PORT CAP

SERVICE PORT
CORE

LIQUID LINE SERVICE VALVE

REFRIGERANT LINE

DO NOT CRIMP SERVICE

VALVE CONNECTOR WHEN

PIPE IS SMALLER THAN

CONNECTION

ATTACH THE MANIFOLD GAUGE SET FOR BRAZING
LIQUID AND SUCTION LINE SERVICE VALVES

3

A. Connect gauge set low pressure side to liquid line

service valve (service port).

B. Connect gauge set center port to bottle of nitrogen

with regulator.

C. With valve core removed from the suction line service

port, nitrogen flow will have an exit point.

SUCTION SERVICE PORT MUST BE OPEN AND

SERVICE PORT CORE REMOVED TO ALLOW

EXIT POINT FOR NITROGEN FLOW

SUCTION LINE

INDOOR

UNIT

C

SUCTION LINE

SERVICE VALVE

SUCTION LINE SERVICE

VALV E

LOW

ATTACH

GAUGES

B

OUTDOOR

UNIT

HIGH

SERVICE PORT
CORE

SERVICE
PORT CAP

LIQUID LINE

LIQUID LINE SERVICE

VALV E

A

Figure 8. Brazing Procedures

17

NITROGEN

XC25

WRAP SERVICE VALVES

To help protect service valve seals during brazing, wrap water-saturated cloths around service valve bodies and copper tube
stubs. Use additional water-saturated cloths underneath the valve body to protect the base paint.

4

FLOW NITROGEN

Flow regulated nitrogen (at 1 to 2 psig) through the

5

refrigeration gauge set into the valve stem port connection
on the liquid service valve and out of the suction / vapor
valve stem port. See steps 3A, 3B and 3C on previous page
and below for manifold gauge setup.

BRAZE LINE SET

Cloths must remain water-saturated throughout the

6

brazing and cool-down process.

A. Braze liquid line to liquid line service valve.

B. Braze suction / vapor line to suction / vapor

service valve.

IMPORTANT !

Use silver alloy brazing rods with 5%
minimum silver alloy for copper-to-copper
brazing and 45% alloy for copper-to-brass
or copper-to-steel brazing.

6B

1. FIRE, PERSONAL INJURY, OR PROPERTY
DAMAGE will result if you do not wrap a water-

saturated cloth around both liquid and suction line
service valve bodies and copper tube stub while
brazing in the line set! The braze, when complete,
must be quenched with water to absorb any
residual heat.

2. Do not open service valves until refrigerant lines
and indoor coil have been leak-tested and
evacuated. Refer to procedures provided in this
supplement.

WHEN BRAZING LINE SET TO

SERVICE VALVES, POINT FLAME

AWAY FROM SERVICE VALVE.

WARNING

SUCTION / VAPOR LINE

WATER-SATURATED CLOTHS

SUCTION / VAPOR SERVICE PORT

MUST BE OPEN AND SERVICE PORT

CORE REMOVED TO ALLOW EXIT

POINT FOR NITROGEN FLOW

IMPORTANT !

Allow braze joint to cool. Apply additional
water-saturated cloths to help cool brazed
joints. Do not remove water-saturated cloths
until piping has cooled. Temperatures above
250ºF will damage valve seals.

6A

LIQUID LINE

WATER-SATURATED

PREPARATION FOR NEXT STEP

After all connections have been brazed, disconnect manifold gauge set from service ports. Apply additional water-saturated

7

cloths to both services valves to cool piping. Once piping is cool, remove all water-saturated cloths. Refer to the unit installation
instructions for the next step in preparing the unit.

CLOTHS

Figure 9. Brazing Procedures (Continued)

XC25

18

Flushing the System

LINE SET AND INDOOR COIL (1 OF 2)

1B

TYPICAL EXISTING FIXED ORIFICE
REMOVAL PROCEDURE (UNCASED COIL

1A

DISTRIBUTOR

ASSEMBLY

A. ON FULLY CASED COILS, REMOVE THE COIL ACCESS AND PLUMBING

PANELS.

B. REMOVE ANY SHIPPING CLAMPS HOLDING THE LIQUID LINE AND DIS

TRIBUTOR ASSEMBLY.

C. USING TWO WRENCHES, DISCONNECT LIQUID LINE FROM LIQUID LINE

ORIFICE HOUSING. TAKE CARE NOT TO TWIST OR DAMAGE DISTRIBU
TOR TUBES DURING THIS PROCESS.

D. REMOVE AND DISCARD FIXED ORIFICE, VALVE STEM ASSEMBLY (IF

PRESENT) AND TEFLON

E. USE A FIELD-PROVIDED FITTING TO TEMPORARILY RECONNECT THE

LIQUID LINE TO THE INDOOR UNIT'S LIQUID LINE ORIFICE HOUSING.

SHOWN)

DISTRIBUTOR TUBES

REMOVE AND DISCARD

WHITE TEFLON

LIQUID LINE ORIFICE HOUSING

TEFLON® RING

FIXED ORIFICE

BRASS NUT

®

(IF PRESENT)

®

WASHER AS ILLUSTRATED ABOVE.

SEAL

LIQUID LINE ASSEMBLY

(INCLUDES STRAINER)

CONNECT GAUGES AND EQUIPMENT FOR
FLUSHING PROCEDURE

2

INV ERT ED HCFC-22
CYLINDER CONTAINS
CLE AN HCFC-22 TO B E
USED FOR FLUSHING.

A

1

VAPOR LINE

SERVICE VALVE

EXISTING

INDOOR

UNIT

LIQUID LINE SERVICE

RECOVERY

CYLINDER

VALV E

VAPOR

LIQUID

OUTDOOR

B

NEW

UNIT

OPENED

C

D

RECOVERY MACHINE

A. INVERTED HCFC-22 CYLINDER WITH CLEAN REFRIGERANT TO THE

VAPOR SERVICE VALVE.

B. HCFC-22 GAUGE SET (LOW SIDE) TO THE LIQUID LINE VALVE.

C. HCFC-22 GAUGE SET CENTER PORT TO INLET ON THE RECOVERY

MACHINE WITH AN EMPTY RECOVERY TANK TO THE GAUGE SET.

D. CONNECT RECOVERY TANK TO RECOVERY MACHINES PER MACHINE

INSTRUCTIONS.

MANIFOLD

LOW

TANK
RETURN

INLET

DISCHARGE

GAUGE

TWO PIECE PATCH PLATE

HIGH

CLOSED

TYPICAL EXISTING EXPANSION VALVE
REMOVAL PROCEDURE (UNCASED COIL
SHOWN)

(UNCASED COIL ONLY)

DISTRIBUTOR

TUBES

OR

A. ON FULLY CASED COILS, REMOVE THE COIL ACCESS AND PLUMBING

B. REMOVE ANY SHIPPING CLAMPS HOLDING THE LIQUID LINE AND DIS

C. DISCONNECT THE EQUALIZER LINE FROM THE CHECK EXPANSION

D. REMOVE THE VAPOR LINE SENSING BULB.

E. DISCONNECT THE LIQUID LINE FROM THE CHECK EXPANSION VALVE

F. DISCONNECT THE CHECK EXPANSION VALVE FROM THE LIQUID LINE

G. REMOVE AND DISCARD CHECK EXPANSION VALVE AND THE TWO TEF

H. USE A FIELD-PROVIDED FITTING TO TEMPORARILY RECONNECT THE

DISTRIBUTOR

ASSEMBLY

MALE EQUALIZER

LINE FITTING

PANELS.

TRIBUTOR ASSEMBLY.

VALVE EQUALIZER LINE FITTING ON THE VAPOR LINE.

AT THE LIQUID LINE ASSEMBLY.

ORIFICE HOUSING. TAKE CARE NOT TO TWIST OR DAMAGE DISTRIBU
TOR TUBES DURING THIS PROCESS.

®

RINGS.

LON

LIQUID LINE TO THE INDOOR UNIT'S LIQUID LINE ORIFICE HOUSING.

LIQUID LINE

SENSING BULB

ORIFICE

HOUSING

EQUALIZER
LINE

STUB END

TEFLON
RING

VAPOR

CHECK

EXPANSION

VALV E

®

LIQUID LINE

ASSEMBLY WITH

BRASS NUT

LINE

TEFLON

RING

SENSING

FLUSHING LINE SET

3

CAUTION -This procedure should not be performed on systems

which contain contaminants (Example, compressor burn out).

THE LINE SET AND INDOOR UNIT COIL MUST BE FLUSHED WITH AT
LEAST THE SAME AMOUNT OF CLEAN REFRIGERANT THAT PRE
VIOUSLY CHARGED THE SYSTEM. CHECK THE CHARGE IN THE

B

FLUSHING CYLINDER BEFORE PROCEEDING.

A. 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 VACU
UM ON THE EXISTING SYSTEM LINE SET AND INDOOR UNIT COIL.

B. INVERT THE CYLINDER OF CLEAN HCFC-22 AND OPEN ITS VALVE

TO ALLOW LIQUID REFRIGERANT TO FLOW INTO THE SYSTEM
THROUGH THE VAPOR LINE VALVE. ALLOW THE REFRIGERANT
TO PASS FROM THE CYLINDER AND THROUGH THE LINE SET
AND THE INDOOR UNIT COIL BEFORE IT ENTERS THE RECOVERY
MACHINE.

C. AFTER ALL OF THE LIQUID REFRIGERANT HAS BEEN RECOV

ERED, SWITCH THE RECOVERY MACHINE TO VAPOR RECOVERY
SO THAT ALL OF THE HCFC-22 VAPOR IS RECOVERED. ALLOW
THE RECOVERY MACHINE TO PULL SYSTEM DOWN TO 0.

D. 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 OFF THE MACHINE.

®

LINE

LIQUID

LINE

XC25

19

FLUSHING LINE SET AND INDOOR COIL (2 OF 2)

TYPICAL NEW CHECK EXPANSION VALVE INSTALLATION PROCEDURE

THIS OUTDOOR UNIT IS DESIGNED FOR USE IN SYSTEMS THAT USE A CHECK EXPANSION VALVE METERING DEVICE. SEE LENNOX XC25
PRODUCT SPECIFICATIONS FOR APPROVED EXPANSION VALVE KIT MATCH-UPS AND APPLICATION INFORMATION.

4

THE EXPANSION VALVE UNIT CAN BE INSTALLED INTERNAL OR
EXTERNAL TO THE INDOOR COIL. IN APPLICATIONS WHERE AN

TWO PIECE

PATCH PLATE

(UNCASED

COIL ONLY)

DISTRIBUTOR

TUBES

DISTRIBUTOR

ASSEMBLY

MALE EQUALIZER LINE

FITTING (SEE

EQUALIZER LINE

INSTALLATION FOR

FURTHER DETAILS)

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

(Uncased Coil Shown)

LIQUID LINE

ORIFICE

HOUSING

STUB

END

TEFLON
RING

EQUALIZER
LINE

EXPANSION

VALV E

®

LIQUID LINE

ASSEMBLY WITH

BRASS NUT

VAPOR

LINE

UNCASED COIL IS BEING INSTALLED IN A FIELD-PROVIDED
PLENUM, INSTALL THE CHECK EXPANSION VALVE IN A MANNER
THAT WILL PROVIDE ACCESS FOR FIELD SERVICING OF THE
EXPANSION VALVE. REFER TO BELOW ILLUSTRATION FOR
REFERENCE DURING INSTALLATION OF EXPANSION VALVE
UNIT.

®

TEFLON

RING

A. REMOVE THE FIELD-PROVIDED FITTING THAT TEMPORARILY RECON

NECTED THE LIQUID LINE TO THE INDOOR UNIT'S DISTRIBUTOR AS

SENSING

LINE

LIQUID LINE

SEMBLY.

B. INSTALL ONE OF THE PROVIDED TEFLON

STUBBED END OF THE EXPANSION VALVE AND LIGHTLY LUBRICATE
THE CONNECTOR THREADS AND EXPOSE SURFACE OF THE TEFLON
RING WITH REFRIGERANT OIL.

C. ATTACH THE STUBBED END OF THE EXPANSION VALVE TO THE LIQUID

LINE ORIFICE HOUSING. FINGER TIGHTEN AND USE AN APPROPRIATELY
SIZED WRENCH TO TURN AN ADDITIONAL 1/2 TURN CLOCKWISE AS IL
LUSTRATED IN THE FIGURE ABOVE, OR 20 FT-LB.

D. PLACE THE REMAINING TEFLON

OF THE EXPANSION VALVE. LIGHTLY LUBRICATE CONNECTOR
THREADS AND EXPOSE SURFACE OF THE TEFLON
FRIGERANT OIL.

E. ATTACH THE LIQUID LINE ASSEMBLY TO THE EXPANSION VALVE. FIN

GER TIGHTEN AND USE AN APPROPRIATELY SIZED WRENCH TO TURN
AN ADDITIONAL 1/2 TURN CLOCKWISE AS ILLUSTRATED IN THE FIGURE
ABOVE OR 20 FT-LB.

9 O'CLOCK TO

3 O'CLOCK

BULB

12

®

BULB

9

WASHER AROUND THE OTHER END

12

11

10

8

7

6

®

RINGS AROUND THE

®

ON LINES SMALLER THAN
7/8”, MOUNT SENSING
BULB BETWEEN THE 9
AND 3 O'CLOCK
POSITIONS.

SENSING BULB INSTALLATION

VAPOR LINE

A. ATTACH THE VAPOR LINE SENSING BULB IN THE PROPER

ORIENTATION AS ILLUSTRATED TO THE RIGHT USING THE
CLAMP AND SCREWS PROVIDED.

NOTE - CONFIRM PROPER THERMAL CONTACT BETWEEN
VAPOR LINE AND CHECK EXPANSION BULB BEFORE INSU
LATING THE SENSING BULB ONCE INSTALLED.

B. CONNECT THE EQUALIZER LINE

FROM THE EXPANSION VALVE TO
THE EQUALIZER VAPOR PORT ON
THE VAPOR LINE. FINGER
TIGHTEN THE FLARE NUT PLUS
1/8 TURN (7 FT-LBS) AS ILLUS
TRATED BELOW.

9

10

11

12

1

8

7

5

6

1/8 TURN

2

3

4

VAPOR LINE

BULB

FLARE SEAL CAP

ON 7/8” AND LARGER LINES,
MOUNT SENSING BULB AT
EITHER THE 4 OR 8 O'CLOCK
POSITION. NEVER MOUNT

12

BULB

NOTE - NEVER MOUNT THE SENSING BULB ON

BOTTOM OF LINE.

THE SENSING BULB ON
BOTTOM OF LINE.

FLARE NUT

1/2 TURN

1

2

3

4

5

®

RING WITH RE

EQUALIZER LINE INSTALLATION

REMOVE AND DISCARD EITHER THE FLARE SEAL CAP OR FLARE
NUT WITH COPPER FLARE SEAL BONNET FROM THE EQUALIZER
LINE PORT ON THE VAPOR LINE AS ILLUSTRATED IN THE FIGURE
TO THE RIGHT.

XC25

20

OR

COPPER FLARE
SEAL BONNET

MALE BRASS EQUALIZER
LINE FITTING

VAPOR LINE

INSTALLING ISOLATION GROMMETS

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

SUCTION LINE

LIQUID LINE

TWO ISOLATION GROMMETS ARE
PROVIDED FOR THE LIQUID AND
SUCTION LINE PIPE PANEL PASS
THROUGH.

REAR VIEW OF UNIT EXTERIOR

PIPING PANEL

IMPORTANT

If this unit is being matched with an approved line set
or indoor unit coil which was previously charged with
mineral oil, or if it is being matched with a coil which was
manufactured before January of 1999, the coil and line
set must be flushed prior to installation. Take care to
empty all existing traps. Polyol ester (POE) oils are
used in Lennox units charged with HFC-410A
refrigerant. Residual mineral oil can act as an insulator,
preventing proper heat transfer. It can also clog the
expansion device, and reduce the system
performance and capacity.
Failure to properly flush the system per the instructions
below will void the warranty.

Leak Testing the System

IMPORTANT

Figure 10. Isolation Grommets

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.

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.

XC25

21

LEAK TEST

LINE SET AND INDOOR COIL

NOTE - NORMALLY, THE HIGH PRESSURE HOSE IS CONNECTED TO THE LIQUID LINE
PORT. HOWEVER, CONNECTING IT TO THE VAPOR PORT BETTER PROTECTS THE
MANIFOLD GAUGE SET FROM HIGH PRESSURE DAMAGE.

LOW

HIGH

CONNECT GAUGE SET

A. CONNECT AN HFC-410A MANIFOLD GAUGE SET HIGH PRESSURE

1

2

HOSE TO THE VAPOR VALVE SERVICE PORT.

B. WITH BOTH MANIFOLD VALVES CLOSED, CONNECT THE CYLINDER

OF HFC-410A REFRIGERANT TO THE CENTER PORT OF THE
MANIFOLD GAUGE SET.

NOTE - LATER IN THE PROCEDURE,
THE HFC-410A CONTAINER WILL BE
REPLACED BY THE NITROGEN
CONTAINER.

NITROGEN

TEST FOR LEAKS

AFTER THE LINE SET HAS BEEN CONNECTED TO THE INDOOR AND OUTDOOR UNITS, CHECK THE LINE SET CON
NECTIONS AND INDOOR UNIT FOR LEAKS. USE THE FOLLOWING PROCEDURE TO TEST FOR LEAKS:

A. 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 (VAPOR ONLY).

B. 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) PRES
SURE]. 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.

C. CONNECT A CYLINDER OF DRY NITROGEN WITH A PRESSURE REGULATING VALVE TO THE CENTER PORT OF THE MANIFOLD

GAUGE SET.

D. 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.

E. 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.

F. AFTER LEAK TESTING, DISCONNECT GAUGES FROM SERVICE PORTS.

HFC-410A

B

MANIFOLD GAUGE SET

TO VAPOR

SERVICE VALVE

OUTDOOR UNIT

A

XC25

Figure 11. System Leak Test

22