Lennox 2SCU13-18, 2SCU13-24, 2SCU13-30, 2SCU13-36, 2SCU13-42 Installation And Maintenance Instructions Manual

INSTALLATION AND MAINTENANCE INSTRUCTIONS

2SCU13 Series

with Dry Nitrogen Holding Charge

Split System Air Conditioner

These instructions must be read and understood completely before attempting installation.

NOTICE TO INSTALLER

This unit is factory-charged with DRY NITROGEN. The unit is intended for installation
in existing HCFC-22 systems. Carefully follow all installation procedures.

WARNING

The equipment covered in this manual is to be installed by trained and experienced
service and installation technicians. Improper installation, modification, service, or use
can cause electrical shock, fire, explosion, or other conditions which may cause personal
injury, death, or property damage. Use appropriate safety gear including safety glasses
and gloves when installing this equipment.

WARNING

Risk of electrical shock. Disconnect all remote power
supplies before installing or servicing any portion of
the system. Failure to disconnect power supplies can
result in property damage, personal injury, or death.

WARNING

Installation and servicing of air conditioning equipment
can be hazardous due to internal refrigerant pressure
and live electrical components. Only trained and
qualified service personnel should install or service
this equipment. Installation and service performed by
unqualified persons can result in property damage,
personal injury, or death.

WARNING

Sharp metal edges can cause injury. When installing
the unit, use care to avoid sharp edges.

TABLE OF CONTENTS

INSTALLATION .................................................... 2

START-UP..........................................................10

OPERATION ...................................................... 14

MAINTENANCE ................................................. 14

CONNECTION DIAGRAMS ............................... 16

WARRANTY ....................................................... 18

*P506874-01*

(P) 506874-01

506874-01 Page 1 of 19Issue 1140

INSTALLATION

Fastener

Torque

Stem Caps

8 ft. lbs.

Service Port Caps

8 ft. lbs.

Sheet Metal Screws

16 in. lbs.

#8 Machine Screws

16 in. lbs.

#10 Machine Screws 28 in. lbs.

Compressor Bolts

90 in. lbs.

General

The 2SCU13 air conditioner, which will also be referred to
in this instruction as the outdoor unit, uses HCFC-22
refrigerant. This outdoor unit is intended as a replacement
outdoor component for use in residential systems which
include an existing indoor coil which is functioning properly.

It is NOT intended for new installations.

This outdoor unit is:

• shipped from the factory with nitrogen holding charge

that must be purged from the unit;

• designed for use with HCFC-22 refrigerant only;

• designed for use in systems that use either a RFC

device (orifice) included with outdoor unit or thermal
expansion valve (TXV). See the 2SCU13 product
specification sheet for approved fixed orifice sizes and
expansion valve kit match ups.

IMPORTANT: The air conditioning unit must have properly
matched system components including indoor unit and
refrigerant metering device. Mismatched equipment may
have an impact on the operation, performance, reliability,
and warranty of the air conditioning unit.

Upon receipt of equipment, carefully inspect it for possible
shipping damage. If damage is found, it should be noted on
the carrier’s freight bill. Take special care to examine the
unit inside the carton if the carton is damaged. Any
concealed damage discovered should be reported to the
last carrier immediately, preferably in writing, and should
include a request for inspection by the carrier’s agent.

If any damages are discovered and reported to the carrier
DO NOT INSTALL THE UNIT, as claim may be denied.

Check the unit rating plate to confirm specifications are
as ordered.
Location of Unit

Outdoor units operate under a wide range of weather
conditions; therefore, multiple factors must be considered
when positioning the unit. The unit must be positioned to
give adequate clearances for sufficient airflow and servicing.
Refer to Figure 1 for installation clearances.

Installation Clearances

Read this entire instruction manual, as well as the
instructions supplied in separate equipment, before
starting the installation. Observe and follow all
warnings, cautions, instructional labels, and tags.
Failure to comply with these instructions could result
in an unsafe condition and/or premature component
failure.

These instructions are intended as a general guide only for
use by qualified personnel and do not supersede any national
or local codes in any way. The installation must comply with
all provincial, state, and local codes as well as the National
Electrical Code (U.S.) or Canadian Electrical Code (Canada).
Compliance should be determined prior to installation.

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

Inspection of Shipment

Torque Table

* A service clearance of 30" must be maintained on one of the sides adjacent

to the control box. Clearance to one of the other three sides must be 36".
Clearance to one of the remaining two sides may be 12" and the final side
may be 6".

A clearance of 24" must be maintained between units.

48" clearance required on top of unit. Maximum soffit overhang is 36".

Figure 1

Slab Mounting

When installing unit at grade level, install on level slab high
enough so that water from higher ground will not collect
around unit (see Figure 2).

Page 2 of 19 506874-01Issue 1140

Table 1

Roof Mounting

Install unit at a minimum of 4" above 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.

Slab Mounting

Discharge Air

Mounting Slab

Ground Level

Building

Structure

Power

Indoor Unit

Thermostat

Outdoor

Unit

Y1 Outdoor Unit

Heat

Cooling

Indoor Blower

R

W1

Y

G

C

R

W

Y

G

C

C Outdoor Unit

Figure 2

Thermostat Designations

See unit wiring diagram for power supply connections.
If the indoor unit is not equipped with a blower relay, one must be field supplied
and installed.

Do not connect C (common) connection between indoor unit and thermostat
except when required by the indoor thermostat. Refer to thermostat installation
instructions. C (common) connection between indoor unit and outdoor unit
required for proper operation.

Electrical Wiring

All field wiring must be done in accordance with the National
Electrical Code (NEC) recommendations, Canadian
Electrical Code (CEC) and CSA Standards, or local codes,
where applicable.

WARNING

Unit must be grounded in accordance with national and local
codes. Failure to ground unit properly can result in personal
injury or death.

Refer to the furnace or blower coil Installation Instructions
for additional wiring application diagrams and refer to unit
rating plate 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.

To facilitate conduit, a hole is in the bottom of the control
box. Connect conduit to the control box using a proper
conduit fitting. Units are approved for use only with copper
conductors. 24V Class II circuit connections are made to
the low voltage pigtails. A complete unit wiring diagram is
located inside the unit control box cover (see also pages
16 and 17 of this instruction).

Figure 3

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.

Refrigerant Piping

WARNING

Refrigerant can be harmful if inhaled. Refrigerant must always
be used and recovered responsibly. Incorrect or irresponsible
use of refrigerant can result in personal injury or death.

Field refrigerant piping consists of liquid and suction lines
from the outdoor unit (sweat connections) to the indoor coil
(flare or sweat connections).

Select line set diameters from Table 2 on page 4 to ensure
that oil returns to the compressor. Size vertical suction riser
to maintain minimum velocity at minimum capacity.
Recommended line length is 50' or less. If more than 50'
line set is required, contact Technical Services at (800) 515-

3501.

Table 2 shows the diameters for line sets up to 100' although
vertical lift applications and trapping requirements need to
be reviewed with Technical Services for line sets over 50'.

3. Install room thermostat on an inside wall that is not subject
to drafts, direct sunshine, or other heat sources.

4. Install low voltage wiring from outdoor to indoor unit and
from thermostat to indoor unit (see Figure 3).

506874-01 Page 3 of 19Issue 1140

Installing Refrigerant Line

During the installation of an air conditioning system, it is
important to properly isolate the refrigerant line to prevent
unnecessary vibration. Line set contact with the structure
(wall, ceiling, or floor) may cause objectionable noise when
vibration is translated into sound. As a result, more energy

Refrigerant Line Set Diameters (in.)

S uc tio n L ine

B T U H

L ine S e t L e ngth a nd S iz e

12 f t. 25 ft. 5 0 ft. 75 ft. 10 0 ft.

18,000 3/4 3/4 3/4 3/4 3/4

24,000 3/4 3/4 3/4 3/4 7/8

30,000 3/4 3/4 3/4 7/8 7/8

36,000 7/8 7/8 7/8 7/8 1-1/8

42,000 7/8 7/8 7/8 1-1/8 1-1/8

48,000 7/8 7/8 7/8 1-1/8 1-1/8

60,000 1-1/8 1-1/8 1-1/8 1-1/8 1-1/8

L iquid L ine

B T U H

L ine S et L ength a nd S iz e

12 f t. 25 ft. 5 0 ft. 75 f t. 100 ft.

18,000 3/8 3/8 3/8 3/8 3/8

24,000 3/8 3/8 3/8 3/8 3/8

30,000 3/8 3/8 3/8 3/8 1/2

36,000 3/8 3/8 3/8 3/8 1/2

42,000 3/8 3/8 3/8 1/2 1/2

48,000 3/8 3/8 3/8 1/2 1/2

60,000 3/8 3/8 3/8 1/2 1/2

Install unit away

from windows

Two 90° elbows installed in lineset
will reduce lineset vibration

Outside Unit Placement

and Installation

Figure 4

Line Set Isolation

Illustrations on the following pages demonstrate procedures
which ensure proper refrigerant line set isolation. Figure 5
shows how to install line sets on horizontal runs. Figure 6
shows how to make a transition from horizontal to vertical.
Figure 7 on page 6 shows how to install line sets on vertical
runs.

For installations exceeding 50', contact

Technical Services at [phone].

Table 2

or vibration can be expected. Close attention to line set
isolation must be observed.

Following are some points to consider when placing and
installing a high-efficiency outdoor unit:

Placement

Be aware that some localities are adopting sound ordinances
based on how noisy the unit is at the neighbor’s home, not at
the original installation. Install the unit as far as possible from
the property line. When possible, do not install the unit directly
outside a bedroom window. Glass has a very high level of
sound transmission. Figure 4 shows how to place the outdoor
unit and line set to reduce line set vibration.

Page 4 of 19 506874-01Issue 1140

Brazing Connection Procedure

1. Cut ends of refrigerant lines square (free from nicks or
dents). Debur the ends. The pipe must remain round;
do not pinch end of line.

2. Before making line set connections, use dry nitrogen to purge
the refrigerant piping. This will help to prevent oxidation and
the introduction of moisture into the system.

3. Use silver alloy brazing rods (5% or 6% silver alloy for
copper-to-copper brazing or 45% silver alloy for copper­to-brass or copper-to-steel brazing) which are rated for
use with HCFC-22 refrigerant.

4. Remove the Schrader core assemblies before brazing
to protect them from damage due to extreme heat.
Replace the cores when brazing is complete.

5. Wrap a wet cloth around the valve body and copper tube
stub to protect them from heat damage during brazing.

6. Braze the line set to the service valve. Quench the joints
with water or a wet cloth to prevent heat damage to the
valve core and opening port. The tube end must stay

bottomed in the fitting during final assembly to ensure
proper seating, sealing, and rigidity.

Anchored

Heavy Nylon

Wire Tie

Wall

Stud

Metal Sleeve

Vapor Line Wrapped

in Armaflex

–

Liquid Line

Wall

Stud

Automotive

Muffler-Type

Hanger

Strap Liquid
Line to Vapor
Line

Metal Sleeve

Vapor Line Wrapped

in Armaflex

–

Liquid Line

Strap Liquid
Line to Vapor
Line

To hang line set from joist or rafter,
use either metal strapping material
or anchored heavy nylon wire ties.

Strapping Material

(around vapor line only)

8’

8’

Tape or Wire Tie

Strap the vapor line to the joist or rafter
at 8 intervals then strap the liquid line
to the vapor line.

’

Floor Joist or

Roof Rafter

Metal Sleeve

Floor Joist or Roof Rafter

Tape or Wire Tie

Wire Tie

(around vapor line only)

Refrigerant Line Sets: Installing Horizontal Runs

Figure 5

Refrigerant Line Sets: Transition from Vertical to Horizontal

506874-01 Page 5 of 19Issue 1140

Figure 6

Model

Part
Number

Drill
Size

2SCU13- 18

2SCU13- 24

2SCU13- 30

2SCU13- 36

2SCU13- 42

2SCU13- 48

2SCU13- 60

100484-07

100484-12

100484-19

100484-24

100484-26

100484-36

100484-43

.055

.062

.070

.076

.078

.089

.096

Refrigerant Line Sets: Installing Vertical Runs (new construction shown)

Outside Wall

Wood Block

Between Studs

IMPORTANT: Refrigerant
lines must not contact wall.

Vapor Line

Liquid Line

Wire Tie

Inside Wall

Strap

Sleeve

Wire Tie

Wire Tie

Strap

Wood Block

Sleeve

Vapor Line Wrapped

with Armaflex

Liquid Line

Caulk

PVC Pipe

Fiberglass
Insulation

Outside Wall

IMPORTANT:

Refrigerant

lines must not

contact structure.

NOTE: Similar installation practices
should be used if line set is to be installed
on exterior of outside wall.

7. Install the factory-supplied fixed orifice (or thermal
expansion valve which is sold separately and which is
approved for use with HCFC-22 refrigerant) in the liquid
line at the indoor coil.

Refrigerant Metering Device

2SCU13 units are designed for use with either fixed orifice
or TXV systems. Refer to the appropriate following section
for information on installing the chosen refrigerant metering
device.

Fixed Orifice Systems

2SCU13 units are shipped with a fixed orifice refrigerant
metering device. See Table 3 for the proper fixed orifice
size for each unit. In nonstandard applications, the fixed
orifice provided with the indoor unit may not be appropriately
sized to be matched with the 2SCU13 unit. If necessary,
replace the existing indoor unit fixed orifice with the orifice
supplied with the 2SCU13 unit. Place the supplied fixed
orifice sticker on the indoor cabinet after installation.

Page 6 of 19 506874-01Issue 1140

Figure 7

Fixed Orifice Data

Figure 8 shows how to install the replacement fixed orifice.
Do not twist distributor tubes when loosening the seal nut from
the orifice housing. Use wrench to back up the distributor.

Table 3

Metering Device Installation

Model

Part
Number

2SCU13-18, -24, -30, -36

2SCU13-42, -48

2SCU13-60

A2TXV01

A2TXV02

H2TXV03

Figure 8

Expansion Valve Systems

Expansion valves equipped with Chatleff-type fittings are
available from the manufacturer. See Table 4 for proper TXV
for each unit.

4. Strap the superheat sensing bulb to the suction header.

If installing an expansion valve on an indoor coil that
previously used a fixed orifice, be sure to remove the existing
fixed orifice. Failure to remove a fixed orifice when installing
an expansion valve to the indoor coil will result in improper
operation and damage to the system.

Manifold Gauge Set

When checking the unit charge, use a manifold gauge set that
is equipped with “low loss” hoses. Do not use a manifold gauge
set with anything other than a “low loss” hose.

Liquid and Suction Line Service Valves

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

Each valve is equipped with a service port which has a factory­installed Schrader valve (see Figure 9 on page 8). A service
port cap protects the Schrader valve from contamination and
serves as the primary leak seal.

To Access the Schrader Port:

TXV Data

Table 4

To install an expansion valve (see Figure 8):

1. Separate the distributor assembly and remove the piston

orifice and used teflon seal. Insert nozzle end of the
expansion valve along with a new teflon seal into the
distributor and tighten to 20 – 30 ft. lbs. Use backup wrench
on all wrench flats. Overtightening will crush the teflon

seal and may cause a leak.

2. Attach liquid line portion of distributor assembly along

with new teflon seal to the inlet of the expansion valve.
Tighten to 20 – 30 ft. lbs. Use backup wrench on all
wrench flats. Overtightening will crush the teflon seal

and may cause a leak.

3. Connect the external equalizer line to the equalizer port

on the suction line and tighten to 8 ft. lbs.

1. Remove the service port cap with an adjustable wrench.

2. Connect gauge to the service port.

3. When testing is completed, replace service port cap.
Tighten finger tight, then an additional 1/6 turn.

To Open Liquid or Suction Line Service Valve:

1. Remove stem cap with an adjustable wrench.

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

3. Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.

To Close Liquid or Suction Line Service Valve:

1. Remove the stem cap with an adjustable wrench.

2. Use a service wrench with a hex-head extension to turn
the stem clockwise to seat the valve. Tighten firmly.

3. Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.

506874-01 Page 7 of 19Issue 1140

Service Valve

Valve Closed

Ball Type Service Valve

(Valve Open)

Use adjustable wrench. To open, rotate stem counterclock­wise 1/4 turn (90°). To close, rotate stem clockwise 1/4 turn
(90°).

Figure 10

Valve Open

Figure 9

Suction Line (Ball Type) Service Valve

Suction line (ball type) service valves function the same way
as the other valves; the difference is in the construction (see
Figure 10).

The ball valve is equipped with a service port with a factory­installed Schrader valve. A service port cap protects the
Schrader valve from contamination and serves as the
primary seal.

Leak Testing

After the line set has been connected to the indoor and
outdoor units, the line set connections and indoor unit must
be checked for leaks.

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.

Using an Electronic Leak Detector

1. Connect the high pressure hose of the manifold gauge
set to the suction valve service port. (Normally the high
pressure hose is connected to the liquid line port;
however, connecting it to the suction ports helps to
protect the manifold gauge set from damage caused by
high pressure.)

2. With both manifold valves closed, connect the cylinder
of HCFC-22 refrigerant. Open the valve on the HCFC­22 cylinder (vapor only).

Page 8 of 19 506874-01Issue 1140

3. Open the high pressure side of the manifold to allow
HCFC-22 into the line set and indoor unit. Weigh in a
trace amount of HCFC-22. (A trace amount is a
maximum of 2 oz. of refrigerant or 3 lbs. pressure.)
Close the valve on the HCFC-22 cylinder and the valve
on the high pressure side of the manifold gauge set.
Disconnect the HCFC-22 cylinder.

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

using high pressure gas such as nitrogen for this
purpose, be sure to use a regulator that can control
the pressure down to 1 or 2 psig.

5. Adjust nitrogen pressure to 150 psig. Open the valve
on the high side of the manifold gauge set to pressurize
the line set and the indoor coil.

Evacuation

Evacuating the system of noncondensables is critical for
proper operation of the unit. Noncondensables are defined
as any gas that will not condense under temperatures and
pressures present during operation of an air conditioning
system. Noncondensables and water vapor combine with
refrigerant to produce substances that corrode copper piping
and compressor parts.

Use a thermocouple or thermistor electronic vacuum gauge
that is calibrated in microns. Use an instrument that reads
down to 50 microns.

6. Evacuate the system to a minimum of 500 microns or
lower. 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 pressure. A rapid
rise in pressure indicates a relatively large leak. If this
occurs, the leak testing procedure must be repeated.

7. When 500 microns or lower is maintained, close the
manifold gauge valves, turn off the vacuum pump, and
disconnect the manifold gauge center port hose from the
vacuum pump. Attach the manifold gauge center port
hose to a nitrogen cylinder with pressure regulator set to
150 psig and purge the hose. Open the manifold gauge
valves to break the vacuum in the system. Close the
manifold gauge valves.

8. 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 system.

9. Reconnect the manifold gauge to the vacuum pump,
turn the pump on, and continue to evacuate the system
until 500 microns is maintained within a 20-minute period
after shutting off the vacuum pump and closing the
manifold gauge valves.

10. When the requirements above have been met,
disconnect the manifold hose from the vacuum pump.

WARNING

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

1. Open liquid and suction line service valves on outdoor
unit.

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

• Low pressure gauge to suction line service valve

• High pressure gauge to liquid line service valve

3. Connect micron gauge.

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

5. Open both manifold valves and start vacuum pump.

506874-01 Page 9 of 19Issue 1140

START-UP

Liquid Line Set
Diameter

Oz. per 5 ft. adjust
from 15 ft. line set*

3/8 in.

3 oz. per 5 ft.

CAUTION

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.

Optimizing System Charge

The outdoor unit should be charged during warm weather.
However, applications arise in which charging must occur in
the colder months. The method of charging is determined
by the unit’s refrigerant metering device and the outdoor
ambient temperature.

Measure the liquid line temperature and the outdoor ambient
temperature as outlined below:

1. Rotate fan to check for frozen bearings or binding.

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

3. After evacuation is complete, attach HCFC-22 cylinder
to system through gauge set, and weigh in liquid
refrigerant.

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

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

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

7. Recheck unit voltage with unit running. Power must be
within range shown on unit nameplate.

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

• Low pressure gauge to suction line service valve

• High pressure gauge to liquid line service valve

2. Close manifold gauge set valves. Connect the center
manifold hose to an upright cylinder of HCFC-22.

3. If room temperature is below 70°F, set the room thermostat
to call for heat. This will create the necessary load for
properly charging the system in the cooling cycle.

4. Use a digital thermometer to record the outdoor ambient
temperature.

5. When the heating demand has been satisfied, switch
the thermostat to cooling mode with a set point of 68°F.
When pressures have stabilized, use a digital
thermometer to record the liquid and suction line
temperatures.

6. The outdoor temperature will determine which charging
method to use. Proceed with the appropriate charging
method.

Refrigerant Charging

This charge is based on a matching indoor coil and outdoor
coil with 15' line set. For varying lengths of line set, refer to
Table 5 for refrigerant charge adjustment.

Refrigerant Charge Adjustment

* If line length is greater than 15 ft., add this amount.

If line length is less than 15 ft., remove this amount.

Table 5

Page 10 of 19 506874-01Issue 1140

Charge Using Weigh-In Method (Fixed Orifice/TXV
Systems)

If the system is void of refrigerant, or if the outdoor ambient
temperature is cool, first locate and repair any leaks then
use the weigh-in method to charge the unit.

1. Recover the refrigerant from the unit.

2. Conduct a leak check, then evacuate as previously
outlined.

3. Weigh in the charge according to the total amount shown
on the unit nameplate.

If weighing facilities are not available or if unit is being
charged during warm weather, follow one of the other
procedures outlined below.

Charge Using Subcooling Method (TXV Systems) –
Outdoor Temperatures 65°F or Above

If charging a TXV system when the outdoor ambient
temperature is 65°F or above, the subcooling method can
be used to charge the unit.

1. With the manifold gauge hose on the liquid service port
and the unit operating stably, use a digital thermometer
to record the liquid line temperature.

2. At the same time, record the liquid line pressure reading.

3. Use a temperature/pressure chart for HCFC-22 to
determine the saturation temperature for the liquid line
pressure reading.

Subcooling Values for

TXV Systems

4. Subtract the liquid line temperature from the saturation
temperature (according to the chart) to determine
subcooling.

5. Compare the subcooling value with those shown in Table

6. If subcooling is greater than shown, recover some
refrigerant. If subcooling is less than shown, add some
refrigerant.

Charge Using Superheat Method (TXV Systems) –
Outdoor Temperatures 65°F or Above

1. With the manifold gauge hose on the suction service
port and the unit operating stably, use a digital
thermometer to record the suction line temperature.

2. At the same time, record the suction line pressure
reading.

3. Use a temperature/pressure chart for HCFC-22 to
determine the saturation temperature for the suction line
pressure reading.

_____ ° Saturation Temperature °F

–

_____ ° Liquid Line Temperature °F

=

_____ ° Subcooling Value °F

4. Subtract the saturation temperature (according to the
chart) from the suction line temperature to determine
the superheat.

5. Compare the superheat value with those shown in Table
7 on page 12. If superheat is greater than shown, add
some refrigerant. If superheat is less than shown,
recover some refrigerant.

Table 6

Charge Using Approach Method (TXV Systems)
– Outdoor Temperatures 65°F or Above

The following procedure is intended as a general guide and
is for use on expansion valve systems only. For best results,
indoor temperature should 70°F to 80°F. Monitor system
pressures while charging.

_____ ° Suction Line Temperature °F

–

_____ ° Saturation Temperature °F

=

_____ ° Superheat Value °F

1. Record outdoor ambient temperature using a digital
thermometer.

2. Attach high pressure gauge set and operate unit for
several minutes to allow system pressures to stabilize.

3. Compare stabilized pressures with those provided in
Table 9 on page 13. Minor variations in these pressures
may be expected due to differences in installations.

Significant differences could mean that the system
is not properly charged or that a problem exists with
some component in the system. Pressures higher

than those listed indicate that the system is overcharged.
Pressures lower than those listed indicate that the
system is undercharged. Verify adjusted charge using
the approach method.

4. Use the same digital thermometer to check liquid line
temperature.

5. Subtract the outdoor ambient temperature from the liquid
line temperature to determine the approach temperature.

506874-01 Page 11 of 19Issue 1140

Table 7

6. Compare the approach value with those shown in Table

8. If the values to do not agree with those provided in
Table 8, add refrigerant to lower the approach
temperature or recover refrigerant from the system to
increase the approach temperature.

Approach Values for TXV Systems

Approach value is the liquid line temperature minus the
outdoor ambient temperature (±1°F).

NOTE: For best results, use the same digital thermometer to
check both outdoor ambient and liquid temperatures.

Table 8

_____ ° Liquid Line Temperature °F

–

_____ ° Outdoor Ambient Temperature °F

=

_____ ° Approach Temperature °F

Check Charge Using Normal Operating Pressures

Use Table 9 to perform maintenance checks. Table 9 is not
a procedure for charging the system. Minor variations in
these pressures may be due to differences in installations.
Significant deviations could mean that the system is not
properly charged or that a problem exists with some
component in the system.

Page 12 of 19 506874-01Issue 1140

Normal Operating Pressures

L – Liquid S – Suction

Values provided above are typical pressures. Indoor unit matchup, indoor air quality, and indoor load will cause pressures to vary.

Table 9

506874-01 Page 13 of 19Issue 1140

OPERATION MAINTENANCE

Outdoor unit and indoor blower cycle on demand from the
room thermostat. When the thermostat blower switch is
moved to the ON position, the indoor blower operates
continuously.

WARNING

Before performing maintenance operations on system,
turn the electric power to unit OFF at disconnect
switch(es). Unit may have multiple power supplies.
Electrical shock could cause personal injury or death.

Maintenance and service must be performed by a qualified
installer or service agency.

At the beginning of each cooling season, the system should
be checked as follows:

1. Clean and inspect condenser coil. Coil may be flushed
with a water hose. Be sure the power is off before using
water to clean the coil.

2. Outdoor fan motor is pre-lubricated and sealed. No
further lubrication is needed.

3. Visually inspect connecting lines and coils for evidence
of oil leaks.

4. Check wiring for loose connections.

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

6. Check amp-draw outdoor fan motor.

Unit Name Plate ________ Actual _________

NOTE: If owner complains of insufficient cooling, the unit
should be gauged and refrigerant charge checked. Refer
to the Refrigerant Charging section on page 10.

Indoor Coil

1. Clean coil, if necessary.

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

3. Check condensate pan line and clean, if necessary.

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.

Page 14 of 19 506874-01Issue 1140

3. Belt drive blowers: Check belt for wear and proper
tension.

4. Check all wiring for loose connections.

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

6. Check amp-draw on blower motor.

Unit nameplate _________ Actual

Start-Up and Performance Checklist

Job Name _______________________________ Job No. ________________ Date ______________

Job Location _____________________________ City ___________________ State ______________

Installer _________________________________ City ___________________ State ______________

Unit Model No.______________ Serial No. ___________________

Service Technician ________________________________________ Nameplate Voltage ______________

Rated Load Ampacity ________ Compressor _______________ Outdoor Fan ___________________

Maximum Fuse or Circuit Breaker________________________

Electrical Connections Tight? Indoor Filter Clean? Supply Voltage (Unit Off) ________________

Indoor Blower RPM _____________ S.P. Drop Over Indoor (Dry) ____________

Outdoor Coil Entering Air Temperature _____________ Voltage with Compressor Operating _____________

Discharge Pressure ___________ Vapor Pressure ____________

Refrigerant Charge Checked? Outdoor Fan Checked?

Refrigerant Lines: Leak Checked? Properly Insulated?

Service Valves: Fully Opened? Caps Tight?

Thermostat: Calibrated? Properly Set? Level?

506874-01 Page 15 of 19Issue 1140

H

C

F

1

DESCRIPTION

KEY COMPONENT

A4 CONTROL - TIMED OFF
B1 COMPRESSOR
B4 MOTOR - OUTDOOR FAN

C12 CAPACITOR - DUAL

HR1 HEATER - COMPRESSOR

K1-1 CONTACTOR - COMPRESSOR

S4 SWITCH - HIGH PRESSURE

S24 SWITCH - LOSS OF CHARGE

FOR USE WITH COPPER CONDUCTORS ONLY. REFER TO UNIT RATING
PLATE FOR MINIMUM CIRCUIT AMPACITY AND MAXIMUM OVERCURRENT
PROTECTION SIZE.

WARNING-­ELECTRIC SHOCK HAZARD, CAN CAUSE INJURY OR DEATH.
UNIT MUST BE GROUNDED IN ACCORDANCE WITH NATIONAL
AND LOCAL CODES.

OUTDOOR

FAN

F

C

H

1

2

3

R S C

C

2

3

1

EQUIPMENT

GROUND

HR1

L2

208-230/60/1

L1

K1-1

BLACK

YELLOW

RED

RED

C12

BLACK

ORANGE

B4

PURPLE

K1

S4

S24

A4

C

Y1

TO 24 VAC

POWER SOURCE

20 VA MINIMUM

NEC CLASS 2

S4 HIGH

PRESSURE

SWITCH

(IF USED)

S24 LOSS

OF CHARGE

SWITCH

(IF USED)

B1

GROUND
LUG

GROUND

L2

L1

208-230/60/1

C

Y1

TO 24 VAC

POWER SOURCE

20 VA MINIMUM

NEC CLASS 2

A4

TIMED OFF

CONTROL

(IF USED)

DUAL

CAPACITOR

RED

COMPRESSOR

CONTACTOR

BLACK

COMPRESSOR

CRANKCASE HEATER

(IF USED)

PURPLE

BLACK

ORANGE

RED

YELLOW

S R

LINE VOLTAGE FACTORY INSTALLED

1

LINE VOLTAGE FIELD INSTALLED

24 VOLT FACTORY INSTALLED

CLASS II VOLTAGE FIELD INSTALLED

Single Phase Wiring Diagram P/N 48352-001

Page 16 of 19 506874-01Issue 1140

Figure 11

Three Phase Wiring Diagram

B4

OUTDOOR

FAN

C1

OUTDOOR FAN

CAPACITOR

A4

TIMED OFF

CONTROL

(IF USED)

PURPLE

BLACK

ORANGE

BLACK

BLACK

RED

T3

T2

T1

BLACK

L3

L2

L1

COMPRESSOR

B1

CRANKCASE HEATER

(IF USED)

HR1

2

3 1

TO 24 VAC

POWER SOURCE

10 VA MINIMUM

NEC CLASS 2

C

Y1

L1
L2
L3

208-230/60/3

GROUND

2

S4 HIGH

PRESSURE

SWITCH

(IF USED)

S24 LOSS

OF CHARGE

SWITCH

(IF USED)

S4

A4

S24

K1

2
3
1

Y1

C

TO 24 VAC

POWER SOURCE

10 VA MINIMUM

NEC CLASS 2

S40

208-230/60/3

GROUND

LUG

COMPRESSOR

CONTACTOR

K1

1

L1

L2

L3

EQUIPMENT

GROUND

HR1

S40

K1-1

BLACK

BLACK

B1

BLACK

ORANGE

B

L

A

C

K

B4

C1

PURPLE

RE

D

1

FOR USE WITH COPPER CONDUCTORS ONLY. REFER TO UNIT RATING
PLATE FOR MINIMUM CIRCUIT AMPACITY AND MAXIMUM OVERCURRENT
PROTECTION SIZE.

WARNING-­ELECTRIC SHOCK HAZARD, CAN CAUSE INJURY

OR DEATH. UNIT MUST BE GROUNDED IN
ACCORDANCE WITH NATIONAL AND LOCAL CODES.

LINE VOLTAGE FACTORY INSTALLED

LINE VOLTAGE FIELD INSTALLED

24 VOLT FACTORY INSTALLED

CLASS II VOLTAGE FIELD INSTALLED

2

JUMPER IS USED WHEN TOC IS NOT USED.

DESCRIPTION

KEY COMPONENT

A4 CONTROL - TIMED OFF
B1 COMPRESSOR
B4 MOTOR - OUTDOOR FAN

C1 CAPACITOR - OUTDOOR FAN
HR1 HEATER - COMPRESSOR
K1-1 CONTACTOR - COMPRESSOR

S4 SWITCH - HIGH PRESSURE

S24 SWITCH - LOSS OF CHARGE
S40 THERMOSTAT - CRANKCASE

1

506874-01 Page 17 of 19Issue 1140

Figure 12

EQUIPMENT LIMITED WARRANTY

APPLIES IN U.S.A. AND CANADA ONLY

FAILURE TO MAINTAIN YOUR EQUIPMENT WILL VOID THIS WARRANTY.

COVERED EQUIPMENT

The following heating and cooling equipment is covered by the Limited
Warranty:

Oil Furnaces:

LG14.

Unit/Duct Heaters: LD24 (all units), LF24 and TUA (100,000 to 400,000 btuh units).
Evaporator Coils: C17.

Air Handlers: ACBX32, CB17, CBH17, TAA.
Condensing Units: 2SCU13LC, 4SCU13LC, TSA.
Heat Pumps: 2SHP13LC, 4SHP13LC, TPA.
Packaged Equipment: KCA, KGA, KHA, TCA, TGA, THA, RGE13, RHP13, RCE13.
Electric Heat Sections: AECB29, ECH16, EH17, ECH24.

ONE (1) YEAR COVERAGE −− ALL APPLICATIONS

The covered equipment and covered components are warranted by the
manufacturer for a period of one (1) year from the date of the original unit
installation, when installed and operated in accordance with the manufac­turer’s recommendations. If, during this period, a covered component fails
because of a manufacturing defect, the manufacturer will provide a free
replacement part to the owner. The owner must pay shipping charges and
all other costs of warranty service.

EXTENDED COVERAGE

This limited warranty provides extended coverage on the components
outlined below. The extended warranty coverage begins with the date of
the original unit installation and represents the total warranty period for the
specific component.

Heat Exchangers:

KGA and TGA (Aluminized −− All applications) −− Ten (10) years.
KGA and TGA (Stainless −− All applications) −− Fifteen (15) years.
RGE13, RHP13 and RCE13 −− Ten (10) years.
LF24 and TUA (Aluminized −− All applications) −− Ten (10) years.
LF24 and TUA (Stainless −− All applications) −− Fifteen (15) years.

LD24 (Aluminized −− All applications) −− Two (2) years.
LD24 (Stainless −− All applications) −− Five (5) years.
LG14 (All applications) −− Five (5) years.

Burners: LG14 −− Three (3) years.

Compressors:2SCU13LC, 2SHP13LC, 4SCU13LC, 4SHP13LC −− Five (5) years.

TSA, TPA −− Five (5) years.
KCA, KGA, KHA, TCA, TGA, THA −− Five (5) years.
RGE13, RHP13, RCE13 −− Five (5) years.

NOTE − If the date of original installation cannot be verified, the warranty
period will be deemed to begin six (6) months after the date of manufac­ture.

COMPONENT AVAILABILITY

In the event that a component covered by this warranty is no longer available, the
manufacturer will, at its option, provide a free suitable substitute component or
allow the owner to purchase an equivalent new unit at a reduced price of 20 per­cent of the list price in effect on the date of the failure. The owner must pay ship­ping charges and all other costs of warranty service.

EXCLUDED COMPONENTS

The following components are not protected by this warranty: cabinets,
cabinet pieces, air filters, driers, refrigerant, belts, wiring, fuses and unit
accessories.

REPAIRS

All repairs of covered components must be made with authorized service

parts by a licensed professional service contractor (or equivalent).

CARE OF EQUIPMENT

This new unit must be properly installed, operated and maintained by a li­censed professional installer (or equivalent) or service agency in accordance
with the unit installation, operation and maintenance instructions provided
with each unit. Failure to provide maintenance per the manufacturer’s instruc­tions will void this warranty. The owner may be asked to provide written docu­mentation of annual and other periodic preventive maintenance.

WARRANTY PROCEDURE

When warranty parts are required:

1 − Be prepared to furnish the following information:

a − Complete model and serial number.
b − Proof of required periodic maintenance, installation date and location

if warranty claim.

c − An accurate description of the problem.
2 − Call your local installing contractor.
3 − If the installing contractor is unable to provide warranty parts, check the

yellow pages for another contractor in your area. If you are unable to se-

cure assistance from a contractor, contact the appropriate manufacturer

listed below:

Lennox Industries Inc. Allied Air Enterprises
P.O. Box 799900 215 Metropolitan Drive
Dallas, TX 75379−9900 West Columbia, SC 29170
1−800−9LENNOX 1−800−448−5872

WARRANTY LIMITATIONS

1 − The manufacturer will not pay labor involved in diagnostic calls, or in re-

moving, repairing, servicing, or replacing parts. Such costs may be cov-

ered by a separate warranty provided by the installing contractor.

2 − This warranty is void if the covered equipment is removed from the origi-

nal installation site.
3 − This warranty does not cover damage or defect resulting from:

a − Flood, wind, fire, lightning, mold, or installation and operation in a cor-

rosive atmosphere, or otherwise in contact with corrosive materials
(chlorine, fluorine, salt, recycled waste water, urine, fertilizers, or oth­er damaging substances or chemicals).

b − Accident, neglect, or unreasonable use or operation of the equip-

ment, including operation of electrical equipment at voltages other
than the range specified on the unit nameplate (includes damages
caused by brownouts), or reverse rotation of compressors or motors
due to improper phasing.

c − Modification, change or alteration of the equipment, except as di-

rected in writing by the manufacturer.

d − Operation with system components (indoor unit, outdoor unit and re-

frigerant control devices) which do not match or meet the specifica­tions recommended by the manufacturer.

e − Operation of packaged gas/electric units (equipped with aluminized

heat exchanger) with mixed air temperatures of less than 45°F (7°C).

f − Operation of furnaces with return air temperatures of less than 60°F

(16°C) or operation of a furnace field−installed downstream from a
cooling coil.

g − Use of contaminated or alternate refrigerant.

The installation of replacement parts under terms of this warranty will not ex-

tend the original warranty period.

The manufacturer makes no express warranties other than the warranty
specified above. All implied warranties, including the implied warranty
of merchantability and fitness for a particular purpose, are excluded to
the extent legally permissible. Should such exclusion or limitation of the
warranty be unenforceable, such implied warranties are in any event
limited to to a period of one (1) year. Liability for incidental and conse­quential damages is excluded. Some states do not allow limitations on
the duration of an implied warranty or the exclusion or limitation of inci­dental or consequential damages, so the limitations or exclusions may
not apply to you.

The manufacturer will not pay electricity or fuel costs, or increases in
electricity or fuel costs, for any reason whatsoever, including additional
or unusual use of supplemental electric heat. This warranty does not
cover lodging expenses.

The manufacturer shall not be liable for any default or delay in perfor­mance under this warranty caused by any contingency beyond its con­trol.

This warranty gives you specific legal rights, and you may also have other
rights which vary from state to state.

NOTE TO CUSTOMER

Please complete information below and retain this warranty for your re­cords and future reference.

Unit Model Number:
Serial Number: Date:
Installing Contractor: Phone:

Litho U.S.A.20112

FORM W−024−L3 −− 3/1/2012

Supersedes 9/1/2011



Page 18 of 19 506874-01Issue 1140