Lennox 14ACX User Manual

INSTALLATION

2011 Lennox Industries Inc.

Dallas, Texas, USA

RETAIN THESE INSTRUCTIONS

FOR FUTURE REFERENCE

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

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.

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.

INSTRUCTIONS

Merit® Series 14ACX Units

CONDENSING UNITS

506645−01
07/11
Supersedes 11/10

TABLE OF CONTENTS

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

General 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Typical Unit Parts Arrangement 3. . . . . . . . . . . . . . . . . . .

Model Number Identification 3. . . . . . . . . . . . . . . . . . . . . .

Operating Manifold Gauge Set and Service Valves 4. . .

Recovering Refrigerant from Existing System 6. . . . . . .

New Unit Placement 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removing and Installing Louvers 8. . . . . . . . . . . . . . . . . .

New or Replacement Line Set 9. . . . . . . . . . . . . . . . . . . . .

Brazing Connections 11. . . . . . . . . . . . . . . . . . . . . . . . . . .

Flushing Line Set and Indoor Coil 14. . . . . . . . . . . . . . . .

Installing Indoor Metering Device 15. . . . . . . . . . . . . . . .

Leak Test Line Set and Indoor Coil 16. . . . . . . . . . . . . . .

Evacuating Line Set and Indoor Coil 17. . . . . . . . . . . . .

Electrical Connections 18. . . . . . . . . . . . . . . . . . . . . . . . . .

Servicing Unit Delivered Void of Charge 22. . . . . . . . . . .

Unit Start−Up 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

System Refrigerant 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

System Operation 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maintenance 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Start−Up and Performance Checklist 30. . . . . . . . . . . . . .

Shipping and Packing List

Litho U.S.A.

IMPORTANT

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

NOTICE TO INSTALLER

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

1  Assembled outdoor unit
1  Refrigerant flow control kit (fixed orifice)
1  Liquid line filter drier

General

It is critical for proper unit operation to place outdoor unit on an

UNIT PLACEMENT

elevated surface as described in Unit Placement section on page 7.

BRAZING LINE SET TO SERVICE VALVES

It is imperative to follow the brazing technique illustrated starting on
page 11 to avoid damaging the service valve’s internal seals.

07/11 506645−01

14ACX Air Conditioners, which will also be referred to in
this instruction as the outdoor unit, uses HFC−410A
refrigerant. This outdoor unit must be installed with a
matching indoor unit and line set as outlined in the Lennox
14ACX Engineering Handbook.

This outdoor unit is designed for use in systems that use
one of the following refrigerant metering devices:

 Thermal expansion valve (TXV)
 Fixed orifice

Page 1

*2P0711* *P506645-01*

Unit Dimensions − Inches (mm)

A

OUTDOOR

COIL FAN

COMPRESSOR

A

DISCHARGE AIR

B

SUCTION AND LIQUID

LINE CONNECTION

OPTIONAL UNIT STANDOFF KIT (4)

SIDE VIEW

Model Numbers A B

14ACX−018−230 24−1/4 (616) 29−1/4 (743)

14ACX−024−230 28−1/4 (724) 33−1/4 (845)

14ACX−030−230 28−1/4 (724) 37−1/4 (946)

14ACX−036−230 28−1/4 (724) 37−1/4 (946)

14ACX−042−230 28−1/4 (724) 29−1/4 (743)

14ACX−041−230 and 14ACX−048−230 28−1/4 (724) 37−1/4 (946)

14ACX−059−230 32−1/4 (819) 37−1/4 (946)

14ACX−047−230 and 14ACX−060−230 32−1/4 (819) 33−1/4 (845)

(FIELD INSTALLED)

SIDE VIEW

506645−01

Page 2

Typical Unit Parts Arrangement

NOTE  Plumbing layout and compressor type may vary between model sizes.

CONTROL

GROUND LUG

CONTACTOR

CUTOUT FOR HIGH

VOLTAGE CONDUIT

NOTE − −041, −047, −048, −059 and −060 only are equipped with crankcase thermostat (S40) and
crankcase heater (HR1).

(K1)

DUAL RUN
CAPACITOR
(C12)

DISCHARGE LINE

COMPRESSOR

HARNESS

CONNECTION

OUTDOOR COIL

CONTROL WIRE
LOOP

CRANKCASE HEATER

THERMOSTAT (S40)

LIQUID LINE SERVICE VALVE

THERMAL SWITCH

(S173) (−036 AND

−060 ONLY)

SEE NOTE

COMPRESS0R (B1)

CRANKCASE HEATER

SEE NOTE

(HR1)

SUCTION LINE SERVICE VALVE

HIGH PRESSURE SWITCH (S4)

Model Number Identification

Nominal SEER

Unit Type

AC = Air Conditioner

Refrigerant

X = R−410A

Figure 1. Typical Unit Parts Arrangement

AC X14 024 −

−−

230

13

Voltage

230 = 208/230V−1phase−60hz

Cooling Capacity − Tons
018 = 1.5

024 = 2
030 = 2.5
036 = 3
041 = 3.5
042 = 3.5
047 = 4
048 = 4
059 = 5
060 = 5

Minor Revision Number

Page 3

14ACX SERIES

CAUTION

IMPORTANT

Physical contact with metal edges and corners while
applying excessive force or rapid motion can result in
personal injury. Be aware of, and use caution when
working near these areas during installation or while
servicing this equipment.

Operating Manifold Gauge Set and
Service Valves

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

TORQUE REQUIREMENTS

When servicing or repairing heating, ventilating, and air
conditioning components, ensure the fasteners are
appropriately tightened. Table 1 lists torque values for
fasteners.

IMPORTANT

Only use Allen wrenches of sufficient hardness (50Rc −
Rockwell Harness Scale minimum). Fully insert the
wrench into the valve stem recess.

Service valve stems are factory−torqued (from 9 ft−lbs for
small valves, to 25 ft−lbs for large valves) to prevent
refrigerant loss during shipping and handling. Using an
Allen wrench rated at less than 50Rc risks rounding or
breaking off the wrench, or stripping the valve stem
recess.

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

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

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

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

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
systems must be capable of handling the higher system
operating pressures. The gauges should be rated for use
with pressures 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 up to 800
psig of pressure with a 4000 psig burst rating.

OPERATING SERVICE VALVES

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

Each valve is equipped with a service port which has a
factory−installed valve stem. Figure 2 provides information
on how to access and operating both angle and ball service
valves.

506645−01

Page 4

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

TO INDOOR

UNIT

(VALVE STEM SHOWN OPEN)
INSERT HEX WRENCH HERE

CLOSED) INSERT HEX
WRENCH HERE

SERVICE PORT

CORE

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

CORE

SERVICE PORT

CAP

TO OUTDOOR

UNIT

BALL (SHOWN
CLOSED)

VALV E
STEM

STEM CAP

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:

 With torque wrench: Finger tighten and

torque cap per table 1.

 Without torque wrench: Finger tighten and

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

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:

9

10

8

11

12

7

6

 With Torque Wrench: Finger tighten and

then torque cap per table 1.

 Without Torque Wrench: Finger tight-

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

9

10

8

11

12

7

6

1/6 TURN

1

2

3

4

5

1/12 TURN

1

2

3

4

5

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

Figure 2. Angle and Ball Service Valves

Page 5

14ACX SERIES

Recovering Refrigerant from Existing System

Use the following procedure to recover refrigerant from an existing system (indoor coil, line set and outdoor unit).

DISCONNECT POWER

Disconnect all power to the existing outdoor unit at the service

12

disconnect switch or main fuse box/breaker panel.

MAIN FUSE BOX/BREAKER PANEL

SERVICE

DISCONNECT

SWITCH

RECOVERING REFRIGERANT

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

3

IMPORTANT  Some system configurations may contain higher than normal refrigerant charge due to either large internal coil volumes,

and/or long line sets.

CONNECT MANIFOLD GAUGE SET

Connect a gauge set, clean recovery cylinder and a recovery
machine to the service ports of the existing unit. Use the
instructions provided with the recovery machine to make the
connections.

MANIFOLD GAUGES

RECOVERY MACHINE

LOW

CLEAN RECOVERY
CYLINDER

OUTDOOR UNIT

HIGH

METHOD 1:

Us this method if the existing outdoor unit is not equipped with shut−off valves, or if the unit is not operational and you plan to use the existing
HCFC−22 to flush the system.

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

METHOD 2:

Use this method if the existing outdoor unit is equipped with manual shut−off valves, and you plan to use new HCFC−22 refrigerant to flush the
system.

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

 Outdoor unit’s high or low−pressure switches (if applicable) when tripped can cycle the compressor OFF.
 Compressor can stop pumping due to tripped internal pressure relief valve.
 Compressor has internal vacuum protection that is designed to unload the scrolls (compressor stops pumping) when the pressure ratio meets

a certain value or when the suction pressure is as high as 20 psig. (Compressor suction pressures should never be allowed to go into a vacuum.
Prolonged operation at low suction pressures will result in overheating of the scrolls and permanent damage to the scroll tips, drive bearings and
internal seals.)

Once the compressor can not pump down to a lower pressure due to one of the above system conditions, shut off the vapor valve. Turn OFF the
main power to unit and use a recovery machine to recover any refrigerant left in the indoor coil and line set.

Perform the following task:

A Start the existing HCFC−22 system in the cooling mode and close the liquid line valve.
B Use the compressor to pump as much of the existing HCFC−22 refrigerant into the outdoor unit until the outdoor system is full. Turn the outdoor unit

main power OFF and use a recovery machine to remove the remaining refrigerant from the system.

NOTE  It may be necessary to bypass the low pressure switches (if equipped) to ensure complete refrigerant evacuation.

C When the low side system pressures reach 0 psig, close the vapor line valve.

D Check gauges after shutdown to confirm that the valves are not allowing refrigerant to flow back into the low side of the system.

Figure 3. Refrigerant Recovery Procedure

506645−01

Page 6

CLEARANCE ON ALL SIDES  INCHES (MILLIMETERS)

MINIMUM CLEARANCE

ABOVE UNIT

12 (305)

6 (152)

36 (914)

ACCESS PANEL

30 (762)

LINE SET
CONNECTIONS

MINIMUM CLEARANCE BETWEEN

TWO UNITS

24 (610)

Figure 4. Installation Clearances

NOTES:

 Clearance to one of the other three

sides must be 36 inches (914mm).

 Clearance to one of the remaining

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

ACCESS PANEL

LINE SET

CONNECTIONS

48 (1219)

DETAIL A

INSTALL UNIT AWAY

FROM WINDOWS

TWO 90 ELBOWS INSTALLED IN LINE SET

WILL REDUCE LINE SET VIBRATION

Figure 5. Placement, and Slab Mounting

New Unit Placement

See Unit Dimensions on page 2 for sizing mounting slab,
platforms or supports. Refer to figure 4 for mandatory
installation clearance requirements.

POSITIONING CONSIDERATIONS

CAUTION

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

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

Consider the following when positioning the unit:

 Some localities are adopting sound ordinances based

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

 When possible, do not install the unit directly outside

a window. Glass has a very high level of sound
transmission. For proper placement of unit in relation
to a window see the provided illustration in figure 5,
detail A.

DISCHARGE AIR

MOUNTING
SLAB

GROUND LEVEL

Page 7

14ACX SERIES

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,
detail B.

ROOF MOUNTING

Install the unit at a minimum of 4 inches (102 mm) above
the surface of the roof. Ensure the weight of the unit is
properly distributed over roof joists and rafters. Redwood
or steel supports are recommended.

Removing and Installing Louvers

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.

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.

When removing the unit panels. Remove panel A first, then B, C and
finally D. When reinstalling panels, reverse that order starting with panel

D, C, B and finally A.

REMOVAL

STEP 1

TO REMOVE PANEL,
REMOVE MOUNTING
SCREWS SECURING
PANEL TO THE UNIT.

PANEL A

STEP 2

SLIGHTLY LIFT PANEL A IN
ORDER TO CLEAR SIDE
LIPS OF PANEL FROM
BASE OF UNIT.

STEP 3

TILT PANEL OUT SLIGHTLY
AND PULL DOWNWARD
TO REMOVE.

REPEAT STEPS 1, 2 AND
3 TO REMOVE PANELS B,
C AND FINALLY D.

PANEL A

PANEL B

WARNING

PANEL A

INSTALLATION

STEP 1

STARTING WITH PANEL D,
INSERT PANEL UNDER UNIT
TOP CAP LIP AND LIFT
SLIGHTLY TO CLEAR SIDE LIP
OF PANEL FROM BASE.

STEP 2

MOVE PANEL IN TOWARDS UNIT.
ALIGN LEFT/RIGHT SIDE LIPS OF
PANEL WITH GROOVE INSERTS
ALONG LEFT/RIGHT SIDE OF UNIT.

SIDE

GROOVE

STEP 3

SECURE PANEL, WITH
MOUNTING SCREWS.

REPEAT STEPS 1 AND 2 TO
INSTALL PANELS C, B AND
FINALLY A.

PANEL C

PANEL D

TOP CAP

BASE

PANEL D

506645−01

Figure 6. Louvers

Page 8

New or Replacement Line Set

This section provides information on new installation or
replacement of existing line set. If a new or replacement
line set is not required, then proceed to Brazing
Connections on page 11.

Field refrigerant piping consists of liquid and suction lines
from the outdoor unit (braze connections) to the indoor unit
coil (flare or braze connections). Use Lennox L15 (braze,
non−flare) series line set, or use field−fabricated refrigerant
lines as listed in table 2.

NOTE − When installing refrigerant lines longer than 50
feet, see the Lennox Refrigerant Piping Design and
Fabrication Guidelines, CORP. 9351−L9, or contact
Lennox Technical Support Product Applications for
assistance.

To obtain the correct information from Lennox, be sure to
communicate the following points:

 Model (14ACX) and size of unit (e.g. −060).
 Line set diameters for the unit being installed as listed

in table 2 and total length of installation.

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

piping.

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.

Recommended topping−off POE oils are Mobil EAL
ARCTIC 22 CC or ICI EMKARATE RL32CF.

MATCHING WITH NEW OR EXISTING INDOOR COIL
AND LINE SET

The RFC1−metering line consisted of a small bore copper
line that ran from condenser to evaporator coil. Refrigerant
was metered into the evaporator by utilizing
temperature/pressure evaporation effects on refrigerant in
the small RFC line. The length and bore of the RFC line
corresponded to the size of cooling unit.

If the 14ACX is being used with either a new or existing
indoor coil which is equipped with a liquid line which served
as a metering device (RFCI), the liquid line must be
replaced prior to the installation of the 14ACX unit.
Typically a liquid line used to meter flow is 1/4" in diameter
and copper.

LIQUID LINE FILTER DRIER INSTALLATION

The filter drier (one is shipped with each 14ACX unit) must
be field installed in the liquid line between the outdoor unit’s
liquid line service valve and the indoor coil’s metering
device (fixed orifice or TXV) as illustrated in figure 7. This
filter drier must be installed to ensure a clean,
moisture−free system. Failure to install the filter drier will
void the warranty. A replacement filter drier is available
from Lennox. See Brazing Connections page 11 for
special procedures on brazing filter drier connections to
the liquid line.

BRAZE CONNECTION POINTS

IMPORTANT

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

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

The compressor is charged with sufficient Polyol ester oil
for line set lengths up to 50 feet. Recommend adding oil to
system based on the amount of refrigerant charge in the
system. No need to add oil in system with 20 pounds of
refrigerant or less. For systems over 20 pounds − add one
ounce of every five pounds of refrigerant.

Table 2. Refrigerant Line Set  Inches (mm)

Model Number

14ACX−018−230

14ACX−024−230

14ACX−030−230

14ACX−036−230

14ACX−041−230

14ACX−042−230

14ACX−047−230

14ACX−048−230

14ACX−059−230

14ACX−060−230

NOTE  Some applications may required a field provided 7/8" to 1−1/8" adapter

Valve Field Size Connections Recommended Line Set

Liquid Line Suction Line Liquid Line Suction Line L15 Series Line Sets

3/8 in. (10 mm) 3/4 in. (19 mm) 3/8 in. (10 mm) 3/4 in. (19 mm)

3/8 in. (10 mm) 7/8 in. (22 mm) 3/8 in. (10 mm) 7/8 in. (22 mm)

3/8 in. (10 mm) 1−1/8 in. (29 mm) 3/8 in. (10 mm) 1−1/8 in. (29 mm) Field Fabricated

LIQUID

LINE

OUTDOOR

UNIT

LIQUID LINE

SERVICE VALVE

LINE

LIQUID LINE

FILTER DRIER

igure 7. Typical Liquid Line Filter Drier Installation

L15−41  15 feet to 50 feet (4.6 meters to
15 meters)

L15−65  15 feet to 50 feet (4.6 meters to
15 meters)

Page 9

14ACX SERIES