Lennox XC25 Series Manual

INSTALLATION

E2013 Lennox Industries Inc.

Dallas, Texas, USA

THIS MANUAL MUST BE LEFT WITH THE

HOMEOWNER FOR FUTURE REFERENCE

General

This XC25 outdoor unit is designed for use with HFC-410A
refrigerant only.

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

IMPORTANT: BEFORE APPLYING ANY POWER (MAIN, SOLAR
OR LOW VOLTAGE) TO THE OUTDOOR UNIT, THE FIELD MUST
CONFIRM ICOMFORT WI-FI® THERMOSTAT HAS VERSION 2.1
OR HIGHER SOFTWARE. (REFERENCE ICOMFORT WI-FI

THERMOSTAT MANUAL)

THIS UNIT IS A INTEGRAL COMPONENT OF A SYSTEM THAT
WILL REQUIRE AN ICOMFORT WI-FI® THERMOSTAT AND
ICOMFORT™ -ENABLED AIR HANDLER OR FURNACE.

iComfort WI-FI

iComfort™-enabled

air handler or

furnace

®

XC25

®

INSTRUCTIONS

Dave Lennox Signature
Collection XC25 System

AIR CONDITIONERS
507004-01
6/14/2013

Supersedes 6/2013

PACKING LIST

GROMMETS (2)

OUTDOOR UNIT

BUSHING (1)

WARRANTY
CARD

WARNING

Improper installation, adjustment, alteration, service or
maintenance can cause property damage, personal inju
ry or loss of life.

Installation and service must be performed by a licensed
HVAC professional installer (or equivalent) or service
agency.

®

Litho U.S.A.

RAST 6-PIN

CONNECTOR (1)

STEP 1 -- SETTING THE UNIT -- Clearances

CLEARANCE ON ALL SIDES — INCHES (MILLIMETERS)

6 (152)

CONTROL

PANEL ACCESS

LOCATION

12 (305)

36 (914)

30 (762)

Note: Dimensions are not to scale.

MINIMUM CLEARANCE BETWEEN TWO UNITS

24

(610)

NOTES:

S Clearance to access panel must be 30

inches (762mm).

S Clearance to one of the other three

sides must be 36 inches (914mm).

S Clearance to one of the remaining two

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

LINE SET

CONNECTIONS

MINIMUM CLEARANCE

ABOVE UNIT

48 (1219)

ACCESS

PANEL

REAR VIEW OF UNIT

6/14/2013 507004-01

*2P6142013* *P507004-01*

FIGURE 1

Page 1

DETAIL A

INSTALL UNIT AWAY FROM WINDOWS

TWO 90° ELBOWS INSTALLED IN LINE SET

WILL REDUCE LINE SET VIBRATION.

Outside Unit Placement

DETAIL B

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.

BUILDING

STRUCTURE

MOUNTING
SLAB

GROUND LEVEL

Slab Mounting at Ground Level

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 HD SCREW

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

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

REQUIRED)

AND FLAT WASHER

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 market
place.

COIL

BASE PAN

Page 2

NOTICE !

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

rubber roofing material may absorb oil, causing the
rubber to degrade. Failure to follow this notice
could result in damage to roof surface.

IMPORTANT !

Exhaust vents from dryers, water heaters and
furnaces should be directed away from the outdoor
unit. Prolonged exposure to exhaust gases and the
chemicals contained within them may cause
condensation to form on the steel cabinet and other
metal components of the outdoor unit. This will
diminish unit performance and longevity.

UNIT DIMENSIONS - INCHES (MM)

WARNING

To prevent personal injury, as well as damage to panels,
unit or structure, observe the following:

While installing or servicing this unit, carefully stow all
removed panels so that the panels will not cause injury
to personnel, objects or nearby structures. Also, take
care to store panels where they will not be subject to
damage (e.g., being bent or scratched).

While handling or stowing the panels, consider any
weather conditions (especially wind) that may cause
panels to be blown around and damaged.

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.

UNIT SUPPORT
FEET

26-7/8

(683)

16-7/8

(429)

8-3/4
(222)

3-1/8

(79)

30-3/4

(781)

BASE WITH ELONGATED LEGS

3-3/4 (95)

4-5/8
(117)

CAUTION

As with any mechanical equipment, contact with sharp
sheet metal edges can result in personal injury. Take
care while handling this equipment.

Page 3

XC25 SERIES

STEP 2 -- REFRIGERANT PIPING -- New or
Existing Line Set and Indoor Coil

Flush existing line set per industry standards. For

more information concerning flushing procedures,
refer to the XC25 Installation and Service Procedures
available on DaveNet.
flush and re-use existing line sets or indoor coil when
the system contains contaminants (i.e., compressor
burn out).

CAUTION - DO NOT attempt to

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 installa
tion. Take care to empty all existing traps. Polyol es
ter (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 sys
tem performance and capacity.

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

WARNING

Polyol ester (POE) oils used with HFC-410A
refrigerant absorb moisture very quickly. It is very
important that the refrigerant system be kept closed
as much as possible. DO NOT remove line set caps
or service valve stub caps until you are ready to make
connections.

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 Haz
ard. 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 fire
and/or an explosion, 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).

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 COM
PRESSOR.

IMPORTANT !

If unit is equipped with a crankcase heater, and outdoor
ambient temperature is below 60°F, unit should be ener
gized 24 hours before startup to prevent compressor
damage as a result of slugging.

The XC25 is a variable capacity cooling and heat pump
system utilizing variable speed compressor technology.
With the variable speed compressor and variable pumping
capacity, additional consideration must be given to refri
gerant piping sizing and application. The guidelines below
are to be used exclusively for the XC25 systems.

COOLING SYSTEM (HFC410A)

S Total equivalent length equals 180 feet (piping and all

fittings included).

NOTE — Length is general guide. Lengths may be more or
less, depending on remaining system design factors.

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

NOTE — Maximum lifts are dependent on total length,
number of elbows, etc. that contribute to total pressure
drop.

S Maximum length vapor riser equals 60 feet.
S Up to 50 Linear Feet: Use rated line sizes listed in

table 1.

S Between 51  150 Linear Feet: Crankcase heater and

nonbleed port TXV factory installed. No additional
components required. Vertical vapor riser must be
sized to the vapor riser listed in the table 2 on systems
with line sets longer than 51 feet. Use tables 2 and 3
to determine the correct liquid and vapor line sizes.

S Over 150 Linear Feet: not recommended.
S Additional oil is not required for systems with line

lengths up to 150 feet.

SUCTION TRAPS

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

Page 4

ADDING REFRIGERANT FOR LONG LINE SETS

WEIGH IN

CHARGING METHOD FOR LONG LINE SETS

64ºF (17.7ºC) and Below

Adjust amount. for variation in

Amount specified

on nameplate

line set length and liquid line
diameter using table below.

+

=

Total charge

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.

NOTE — The above nameplate is for illustration purposes only. Go to
actual nameplate on outdoor unit for charge information.

Charging Formula for Liquid Line Charge Adjustments

Liquid Line

Set Diameter

5/16”

3/8”

1/2”

HFC-410A

(ounces per foot)

0.40

0.60

1.00

[(Line set oz./ft. x total length)  (factory charge for line set)] = charge adjustment

Example: Units are factorycharged for 15 feet (4.6 meters) of 3/8" line set.
Factory charge for 3/8" is 0.60 oz/ft x 15 = 9.0 ounces.

Figure 2. Using HFC-410A Weigh In Method

Table 1. Standard Refrigerant Line Set — Up to 50 Linear Feet

Inches (mm)

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

Model Number (-xx*) Liquid Line Suction Line L15 Line Set Model Line Set Length Catalog Number

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 required a field-provided 1-1/8” to 7/8” adapter.

3/8” (10 mm) 7/8” (22 mm)

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

Table 2. XC25 Line Set Guidelines Between — 51  150 Linear Length

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

Table 3. Liquid Line Diameter Selection Table

Unit Line Size

024

036

048

060

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) on 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. Select or consider the larger liquid line size shown in the table if the elevation does not meet your requirements.

NOTE - For new or replacement line set installation, refer to Service and Application Note - Corp. 9112-L4 (C-91-4).

5/16”

3/8”
3/8”
1/2”
3/8”
1/2”
3/8”
1/2”

25 50 75 100 125 150

25
25
25
25
25
25
25
25

50 55 48 40 33
50 60 60 60 60
50 60 56 51 45
50 60 60 60 60
50 50 41 31 22
50 60 60 60 60
50 36 22 8 NR
50 60 60 60 59

Total Linear Length (feet)

Required Vapor

Riser Size

Max. Elevation

(ft)

Page 5

XC25 SERIES

STEP 2 -- REFRIGERANT PIPING -- Removing Existing Indoor Metering Device

TYPICAL EXISTING FIXED ORIFICE

1A

DISTRIBUTOR

ASSEMBLY

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

7. Remove any shipping clamps from the liquid line and distributor as

sembly.

8. Using two wrenches, disconnect liquid line from liquid line orifice hous

ing. Take care not to twist or damage distributor tubes during this pro
cess.

9. Remove and discard fixed orifice, valve stem assembly (if present)

and Teflon® washer as illustrated above.

10. Use a field-provided fitting to temporarily reconnect the liquid line to the

indoor unit's liquid line orifice housing.

(UNCASED COIL SHOWN)

DISTRIBUTOR TUBES

LIQUID LINE ORIFICE HOUSING

TEFLON® RING

FIXED ORIFICE

REMOVE AND DISCARD

WHITE TEFLON

(IF PRESENT)

®

SEAL

LIQUID LINE ASSEMBLY

(INCLUDES STRAINER)

REMOVAL PROCEDURE

OR

BRASS NUT

1B

TWO-PIECE PATCH PLATE

CONNECT GAUGES AND EQUIPMENT FOR
FLUSHING PROCEDURE

2

CYLINDER CONTAINING
CLEAN HCFC-22 TO BE
USED FOR FLUSHING
(Positioned to deliver liquid

A

refrigerant)

1

VAPOR LINE

SERVICE VALVE

EXISTING

INDOOR

UNIT

LIQUID LINE SERVICE

VALV E

RECOVERY

CYLINDER

VAPOR

LIQUID

OUTDOOR

B

NEW

UNIT

OPENED

C

D

RECOVERY MACHINE

1. HCFC-22 cylinder with clean refrigerant (positioned to deliver liquid

refrigerant) to the vapor service valve.

2. HCFC-22 gauge set (low side) to the liquid line valve.

3. HCFC-22 gauge set center port to inlet on the recovery machine with an

empty recovery tank connected to the gauge set.

4. Connect recovery tank to recovery machine per machine instructions.

GAUGE

MANIFOLD

LOW HIGH

CLOSED

TANK
RETURN

INLET

DISCHARGE

TYPICAL EXISTING EXPANSION VALVE REMOVAL
PROCEDURE (UNCASED COIL SHOWN)

ORIFICE

HOUSING

EQUALIZER
LINE

STUB END

TEFLON
RING

VAPOR

EXPANSION

VALV E

®

LIQUID LINE

ASSEMBLY WITH

BRASS NUT

LINE

TEFLON

RING

®

SENSING

LINE

LIQUID

(UNCASED COIL ONLY)

DISTRIBUTOR

TUBES

DISTRIBUTOR

ASSEMBLY

MALE EQUALIZER

LINE FITTING

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

2. Remove any shipping clamps from the liquid line and distributor

assembly.

3. Disconnect the equalizer line from the check expansion valve

equalizer line fitting on the vapor line.

4. Remove the vapor line sensing bulb.

5. Disconnect the liquid line from the check expansion valve at the liquid

line assembly.

6. Disconnect the check expansion valve from the liquid line orifice

housing. Take care not to twist or damage distributor tubes during this
process.

7. Remove and discard check expansion valve and the two Teflon® rings.

8. Use a field-provided fitting to temporarily reconnect the liquid line to the

indoor unit's liquid line orifice housing.

LIQUID LINE

SENSING BULB

FLUSHING LINE SET

The line set and indoor unit coil must be flushed with at least the same

3

amount of clean refrigerant that previously charged the system. Check
the charge in the flushing cylinder before proceeding.

1. 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.

2. Position the cylinder of clean HCFC-22 for delivery of liquid refrigerant

3. After all of the liquid refrigerant has been recovered, switch the

4. Close the valve on the inverted HCFC-22 drum and the gauge set

B

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.

recovery machine to vapor recovery so that all of the HCFC-22 vapor
is recovered. Allow the recovery machine to pull the system down to 0.

valves. Pump the remaining refrigerant out of the recovery machine
and turn the machine off.

LINE

FIGURE 3

Page 6

STEP 2 -- REFRIGERANT PIPING -- Brazing Procedures

PIPING PANEL REMOVAL / PREPARING LINE SET

Remove piping panel to access service valves. Cut

1

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

CONNECTION

STUB

REFRIGERANT LINE

LINE SET SIZE IS SMALLER

THAN CONNECTION

CAP AND CORE REMOVAL

Remove service cap and core from both the suction /

2

vapor and liquid line service ports.

SERVICE PORT CAP

SERVICE PORT
CORE

LIQUID LINE SERVICE VALVE

SERVICE PORT
CORE

SERVICE
PORT CAP

SUCTION / VAPOR LINE

DO NOT CRIMP SERVICE VALVE

CONNECTOR WHEN PIPE IS

SMALLER THAN CONNECTION

SERVICE VALVE

ATTACH THE MANIFOLD GAUGE SET FOR BRAZING
LIQUID AND SUCTION / VAPOR 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 / vapor line service port, nitrogen flow will have an exit point.

HIGHLOW

ATTACH

GAUGES

SUCTION / VAPOR SERVICE PORT MUST BE

OPEN AND SERVICE PORT CORE REMOVED

TO ALLOW EXIT POINT FOR NITROGEN FLOW

SUCTION / VAPOR

LINE

INDOOR

UNIT

LIQUID LINE

C

LIQUID LINE SERVICE

SUCTION /

VAPOR LINE

SERVICE

VALV E

VALV E

A

B

OUTDOOR

UNIT

NITROGEN

FIGURE 4

Page 7

XC25 SERIES

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.

WRAP SERVICE VALVES

To help protect service valve seals during brazing, wrap water-saturated cloths around service valve bodies and copper tube stubs. Use

4

additional water-saturated cloths under the valve body to protect the base paint.

FLOW NITROGEN

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

5

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 brazing and

6

cool-down process.

1. Braze liquid line to liquid line service valve.

2. Braze suction / vapor line to suction / vapor service

valve.

FIRE, PERSONAL INJURY, OR PROPERTY DAMAGE

may 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 the line set! The braze, when
complete, must be quenched with water to absorb any
residual heat.

Do not open service valves until refrigerant lines and
indoor coil have been leak-tested and evacuated. Refer
to Installation and Service Procedures manual found on
DAVENET.

WARNING

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

WARNING

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.

SUCTION / VAPOR LINE

WATER-SATURATED CLOTHS

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.

LIQUID LINE

6B

6A

WHEN BRAZING LINE SET TO

SERVICE VALVES, POINT FLAME

AWAY FROM SERVICE VALVE.

SUCTION / VAPOR SERVICE

PORT MUST BE OPEN AND

SERVICE PORT CORE RE

MOVED TO ALLOW EXIT POINT

FOR NITROGEN FLOW

PREPARATION FOR NEXT STEP

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

7

services valves to cool piping. Once piping is cool, remove all water-saturated cloths.

WATER-SATURATED

FIGURE 5

Page 8

CLOTHS

STEP 3 -- INSTALLING INDOOR EXPANSION VALVE

This outdoor unit is designed for use in systems that include an expansion valve metering device. See the XC25 Product
Specifications bulletin (EHB) for approved expansion valve kit match-ups and application information. The expansion valve

can be installed internal or external to the indoor coil. In applications where an uncased coil is being installed in a field-pro
vided plenum, install the expansion valve in a manner that will provide access for future field service of the expansion valve.
Refer to below illustration for reference during installation of expansion valve.

INDOOR EXPANSION VALVE INSTALLATION

TWO-PIECE

PATCH PLATE

(UNCASED

COIL ONLY)

DISTRIBUTOR

TUBES

DISTRIBUTOR

ASSEMBLY

MALE EQUALIZER LINE

FITTING (SEE

EQUALIZER LINE

INSTALLATION FOR

DETAILS)

(Uncased Coil Shown)

LIQUID LINE

ORIFICE

HOUSING

STUB

END

TEFLON
RING

EQUALIZER
LINE

VAPOR

EXPANSION

VALV E

®

ASSEMBLY WITH

LINE

TEFLON

LIQUID LINE

BRASS NUT

RING

®

SENSING

LINE

Sensing bulb insulation is required if
expansion valve is installed external to the
coil casing. See sensing bulb installation for

LIQUID LINE

bulb positioning.

EQUALIZER LINE INSTALLATION

1. 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 below.

2. Remove the field-provided fitting that temporarily reconnected

the liquid line to the indoor unit's distributor assembly.

3. Install one of the provided Teflon® rings around the

stubbed end of the expansion valve and use refrigerant
oil to lightly lubricate the connector threads and ex
posed surface of the Teflon

®

ring.

4. Attach the stubbed end of the expansion valve to the

liquid line orifice housing. Finger tighten, then use an
appropriately sized wrench to turn an additional 1/2
turn clockwise as illustrated in the figure to the right, or
tighten to 20 ft-lb.

5. Place the remaining Teflon

end of the expansion valve. Lightly lubricate connector
threads and expose surface of the Teflon

®

washer around the other

®

ring with

refrigerant oil.

6. Attach the liquid line assembly to the expansion valve.

Finger tighten, then use an appropriately sized wrench
to turn an additional 1/2 turn clockwise as illustrated in
the figure above or tighten to 20 ft-lb.

SENSING BULB INSTALLATION

1. Attach the vapor line sensing bulb in the proper orienta

tion as illustrated below using the clamp and screws
provided.

2. NOTE - Though it is preferred to have the sensing bulb

installed on a horizontal run of the vapor line, installation
on a vertical run of piping is acceptable if necessary.

NOTE — Confirm proper thermal contact between vapor line
and expansion bulb before insulating the sensing bulb.

3. Connect the equalizer line from the expansion valve to

the equalizer vapor port on the vapor line. Finger tighten
the flare nut, then tighten an additional 1/8 turn (7 ft-lbs)
as illustrated to the right.

VAPOR LINE

BULB

12

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

BULB

1/2 Turn

11

10

9

8

7

1/8 Turn

11

10

9

8

7

12

1

2

3

4

5

6

12

1

2

3

4

5

6

FLARE SEAL CAP

OR

FLARE NUT

COPPER FLARE
SEAL BONNET

MALE BRASS EQUALIZER
LINE FITTING

VAPOR LINE

FIGURE 6

Page 9

VAPOR LINE

12

BULB

NOTE — NEVER MOUNT THE SENSING

BULB ON BOTTOM OF LINE.

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

BULB

XC25 SERIES

STEP 4 -- LEAK TEST AND EVACUATION

HIGHLOW

MANIFOLD GAUGE SET

OUTDOOR UNIT

B

TO VAPOR

SERVICE VALVE

NOTE - Position
canister to deliver
liquid refrigerant.

NITROGEN

CONNECT GAUGE SET

A. Connect the high pressure hose of an HFC-410A manifold gauge set to the vapor valve service port.

1

2

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.

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.

TEST FOR LEAKS

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

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) refriger
ant 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.

C. Connect a cylinder of nitrogen with a pressure regulating valve to the center port of the manifold

gauge set.

D. Adjust 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

A

FIGURE 7

Page 10

STEP 4 -- LEAK TEST AND EVACUATION (Continued)

EVACUATION

CONNECT GAUGE SET

NOTE — Remove cores from service valves (if not already done).

3

A. Connect low side of manifold gauge set with

1/4 SAE in-line tee to vapor line service valve

B. Connect high side of manifold gauge set to

liquid line service valve

C. Connect available micron gauge connector

on the 1/4 SAE in-line tee.

D. Connect the vacuum pump (with vacuum

gauge) to the center port of the manifold
gauge set. The center port line will be used
later for both the HFC-410A and nitrogen
containers.

NITROGEN

NOTE - Position
canister to deliver
liquid refrigerant.

HFC-410A

VACUUM PUMP

OUTDOOR

UNIT

A

B

1/4 SAE TEE WITH SWIVEL
COUPLER

500

C

MICRON

GAUGE

GAUGE SET

TO VAPOR

SERVICE VALVE

TO LIQUID LINE
SERVICE VALVE

LOW

MANIFOLD

D

EVACUATE THE SYSTEM

4

A. Open both manifold valves and start the vacuum pump.
B. 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. A rapid rise in pressure indicates a
relatively large leak. If this occurs, repeat the leak testing procedure.

NOTE — The term absolute pressure means the total actual pressure above zero within a given volume or system. Absolute pressure in a
vacuum is equal to atmospheric pressure minus vacuum pressure.

C. When the absolute pressure reaches 23,000 microns (29.01 inches of mercury),

perform the following:

S Close manifold gauge valves.
S Close valve on vacuum pump.
S Turn off vacuum pump.

S Disconnect manifold gauge center port hose from vacuum pump.
S Attach manifold center port hose to a nitrogen cylinder with pressure

regulator set to 150 psig (1034 kPa) and purge the hose.

S Open manifold gauge valves to break the vacuum in the line set and indoor

unit.

S Close manifold gauge valves.

D. Shut off the nitrogen cylinder and remove the manifold gauge hose from the cylinder. Open the manifold gauge valves to release the nitrogen

from the line set and indoor unit.

E. 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.

F. When the absolute pressure requirement above has been met, disconnect the manifold hose from the vacuum pump and connect it to a

cylinder of HFC-410A positioned to deliver liquid refrigerant. Open the manifold gauge valve 1 to 2 psig in order to release the vacuum in the line
set and indoor unit.

G. Perform the following:

S Close manifold gauge valves.
S Shut off HFC-410A cylinder.

S Reinstall service valve cores by removing manifold hose from service valve. Quickly install cores with core

tool while maintaining a positive system pressure.

S Replace stem caps and finger tighten them, then tighten an additional one-sixth (1/6) of a turn as illustrated.

Possible equipment damage.

Avoid deep vacuum operation. Do not use
compressors to evacuate a system.
Extremely low vacuum can cause internal
arcing and compressor failure. Damage
caused by deep vacuum operation will
void warranty.

WARNING !

RECOMMEND

MINIMUM 3/8” HOSE

1/6 TURN

12

11

10

9

8

7

HIGH

1

2

3

4

5

6

FIGURE 8

Page 11

XC25 SERIES

STEP 5 -- ELECTRICAL -- Circuit Sizing and Wire Routing

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 cur
rent Canadian Electrical Code (CEC).

Refer to the furnace or air handler installation instructions
for additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.

24VAC TRANSFORMER

Use the transformer provided with the furnace or air han
dler for low‐voltage control power (24VAC - 40 VA mini
mum)

ELECTROSTATIC

DISCHARGE

(ESD)

Precautions and

Procedures

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.

CAUTION

Electrostatic discharge can affect
electronic components. Take care
during unit installation and service to
protect the unit's electronic controls.
Precautions will help to avoid control
exposure to electrostatic discharge by
putting the unit, the control and the
technician at the same electrostatic
potential. Touch hand and all tools on an
unpainted unit surface before
performing any service procedure to
neutralize electrostatic charge.

SIZE CIRCUIT AND INSTALL DISCONNECT
SWITCH

1

Refer to the unit nameplate for minimum circuit
ampacity, and maximum fuse or circuit breaker size
(HACR per NEC). Install power wiring and properly
sized disconnect switch.

SERVICE

DISCONNECT

SWITCH

NOTE — Units are approved for use only with copper
conductors. Ground unit at disconnect switch or
connect to an earth ground.

FIGURE 9

INSTALL THERMOSTAT

Install room thermostat (ordered separately) on an

2

inside wall in the center of the conditioned area and
5 feet (1.5m) from the floor. The thermostat should
not be installed on an outside wall or where it can be
affected by sunlight or drafts.

THERMOSTAT

5 FEET

(1.5M)

NOTE — 24VAC, Class II circuit connections are made
in the control box.

Page 12

3 -- ELECTRICAL (Continued) -- Master Control Jumper and Terminals

7-SEGMENT

DISPLAY

PUSH

BUTTON

PUMP DOWN - WHEN UNIT IS IN PUMP DOWN MODE, Pd WILL BE

TO ACTIVATE PUMP DOWN MODE, THE CONTROL MUST BE IN

THE IDLE STATE, AND THE PUMP DOWN JUMPER PLACED

ACROSS THE TWO PUMP DOWN PINS. TO DEACTIVATE,

DISPLAYED ON 7-SEGMENT.

REMOVE JUMPER.

FIGURE 10

Page 13

XC25 SERIES

ROUTE CONTROL WIRES

Maximum length of wiring (18 gauge) for all connections on

4

the RSBus is 1500 feet (457 meters). Wires should be color­coded, with a temperature rating of 95ºF (35ºC) minimum,
and solid-core (Class II Rated Wiring). All low voltage wiring
must enter unit through provided field-installed busing
installed in electrical inlet.

The icomfort Wi-Fi
wires between the thermostat and the furnace / air handler
iComfort™ control and four wires between the outdoor unit
and the furnace/air handler iComfort™ control. When a
thermostat cable with more than four wires is used, the extra
wires must be properly connected to avoid electrical noise
(see below).

Use a wire nut to bundle the four unused wires at each end
of the cable. Each bundle should also include an additional
wire that should be connected on each end to the C terminal
as shown in the figure below.

®

thermostat requires four thermostat

ELECTRICAL (CONTROL WIRING)

AND LINE SET INLETS USE

BUSHING AND GROMMETS

PROVIDED IN BAG

BUSHING

GROMMETS

Indoor Control

TYPICAL CONTROL BOX

CONTROL WIRING
ROUTE (LOW VOLTAGE)

OUTDOOR CONTROL

Outdoor Control

PROVIDED RAST

6-PIN CONNECTOR

Single Wire To

C Terminal

Unused Wires

Single Wire To C Terminal

Unused Wires

ROUTE HIGH VOLTAGE AND GROUND WIRES

Any excess high voltage field wiring should be trimmed and secured away from any low voltage field wiring. To facilitate a conduit, a

5

cutout is located side panel of the control box. Connect conduit to the control box using a proper conduit fitting.

GROUND LUGS

ELECTRICAL INLET

(HIGH VOLTAGE)

iComfort Wi-Fi

thermostat

CONTACTOR

®

WATERTIGHT FLEX

IBLE CONDUIT

TO SERVICE

DISCONNECT BOX

FIGURE 11

Page 14

Charging

IMPORTANT !

The XC25 unit is factory-charged with enough HFC-410A
refrigerant to accommodate a 15-foot length of refrigerant
piping. Charge should be checked and adjusted using the
tables provided on the charging procedure sticker located
on the unit access panel. Detailed charging information is
provided in the XC25 Installation and Service Procedures
Corp. 1253-L11, which is available on DaveNet.

IMPORTANT !

Room thermostat must be turned down at least 5°F
from set point so charging occurs with system
operating at 100% capacity. Seven-segment display
on outdoor control will show outdoor unit running
capacity.

Alarms

Alarm information is provided on on the outdoor unit ac
cess panel and in the iComfort Wi-Fi® Installer's System
Setup Guide. Detail alarm information is also available in
the XC25 Installation and Service Procedures Corp.
1253-L11, which is available on DaveNet.

Outdoor Control Seven-Segment Display
and Push Button

Information concerning the outdoor control seven-seg
ment display and push button operations are available on
the unit access panel and in the XC25 Installation and Ser
vice Procedures Corp. 1253-L11.

System Component Configuration
(Outdoor Unit)

All configuration of the outdoor unit is completed using the
iComfort Wi-Fi® thermostat. Please refer to the iComfort

Wi-Fi® Installer's System Setup Guide for complete details

on how to integrate this unit into a iComfort™-enabled sys
tem.

Homeowner Information

CAUTION

Before attempting to perform any service or mainte
nance, turn the electrical power to unit OFF at discon
nect switch.

Cleaning of the outdoor unit's coil should be performed by
a licensed professional service technician (or equivalent).
Contact your dealer and set up a schedule (preferably
twice a year, but at least once a year) to inspect and ser
vice your outdoor unit. The following maintenance may be
performed by the homeowner.

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, diminish performance
and affect longevity of the unit.

Outdoor Coil

The outdoor unit must be properly maintained to ensure its
proper operation.

S Please contact your dealer to schedule proper inspec

tion and maintenance for your equipment.

S Make sure no obstructions restrict airflow to the outdoor

unit.

S Grass clippings, leaves, or shrubs crowding the unit can

cause the unit to work harder and use more energy.

S Keep shrubbery trimmed away from the unit and periodi

cally check for debris which collects around the unit.

S Keep snow level below the louvered panels to ensure

proper performance.

Routine 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.

NOTE — The filter and all access panels must be in place
any time the unit is in operation. If you are unsure about the
filter required for your system, call your Lennox dealer for
assistance.

1. 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 filters should be replaced with a filter of the
same type and size.

3. The indoor 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.)

Thermostat Operation

See the iComfort Wi-Fi® thermostat homeowner manual
for instructions on how to operate your thermostat.

Preservice Check

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

S Verify room thermostat settings are correct.
S Verify that all electrical disconnect switches are ON.
S Check for any blown fuses or tripped circuit breakers.
S Verify unit access panels are in place.
S Verify air filter is clean.
S If service is needed, locate and write down the unit

model number and have it handy before calling.

Page 15

XC25 SERIES

XC25 Start-Up and Performance Checklist

Customer Address

Indoor Unit Model Serial

Outdoor Unit Model Serial

Solar Module Mfg and 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

Vapor Pressure: Liquid Pressure:

Supply Air Temperature: Ambient Temperature: Return Air Temperature:

HEATING MODE

Vapor 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)

A — B = SUBCOOLING

minus Liquid Line Temperature (B)

Approach:

Liquid Line Temperature (A)

A — B = APPROACH

minus Outdoor Air Temperature (B)

Indoor Coil Temp. Drop (18 to 22°F)

Return Air Temperature (A)

A — B = COIL TEMP DROP

minus Supply Air Temperature (B)

Page 16