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 WARNING

Improper installation, adjustment, alteration, service 

or maintenance can cause property damage, personal 

injury or loss of life. Installation and service must  be 

performed by a licensed professional HVAC installer or 

equivalent, service agency, or the gas supplier.

 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.

 CAUTION

As with any mechanical equipment, contact with sharp 

sheet metal edges can result in personal injury. Take 

care while handling this equipment and wear gloves and 

protective clothing.

 WARNING

Electric Shock Hazard. Can cause injury or 

death. Unit must be properly grounded in 

accordance with national and local codes.
Line voltage is present at all components when 

unit is not in operation on units with single-

pole contactors. Disconnect all remote electric 

power supplies before opening access panel. 

Unit may have multiple power supplies.

ML14XC1 

3-PHASE

Table of Contents

Model Number Identification

 ...........................................2

Typical Serial Number Identification

 ...............................2

Specifications 

 ................................................................3

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

Unit Dimensions – Inches (mm)  ....................................4

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

Operating Gauge Set and Service Valves ......................6

Installation ......................................................................8

Unit Placement  ..............................................................8

Removing and Installing Louvered Panels ...................10

New or Replacement Line Set ...................................... 11

Brazing Connections  ...................................................13

Flushing Line Set and Indoor Coil ................................16

Installing Indoor Metering Device .................................17

Leak Testing the System  .............................................18

Evacuating Line Set and Indoor Coil  ...........................19

Electrical – Circuit Sizing and Wire Routing  ..................20

Maintenance   ...............................................................24

Typical Field Wiring ......................................................26

Servicing Units Delivered Void of Charge  ...................26

Unit Start-Up   ...............................................................27

System Refrigerant   .....................................................27

Service Literature

UNIT INFORMATION

Corp. 100047 

April 21, 2022

ML14XC1 (HFC-410A) SERIES OUTDOOR UNITS (3-PHASE)

 IMPORTANT

This unit must be matched with an indoor coil as specified 

with AHRI.  For AHRI  Certified  system  match-ups  and 

expanded ratings, visit www.LennoxPros.com. Coils 

previously charged with HCFC-22 must be flushed.

General Information 

This ML14XC1 outdoor air conditioner 

with all-aluminum 

coil

 is designed for use with HFC-410A refrigerant only. 

This unit must be installed with an approved indoor air 

handler or coil. For AHRI Certified system match-ups and 

expanded ratings, visit www.LennoxPros.com. These in-

structions are intended as a general guide and do not su-

persede local codes in any way. Consult authorities hav-

ing jurisdiction before installation.
This outdoor unit is designed for use in systems that use 

the following refrigerant metering device:
•  Thermal expansion valve (CTXV)

IMPORTANT

: Special procedures are required for clean-

ing the aluminum coil in this unit. See page 24 in this man-

ual for information.

Summary of Contents for ML14XC1 Series

Page 1: ...d Service Valves 6 Installation 8 Unit Placement 8 Removing and Installing Louvered Panels 10 New or Replacement Line Set 11 Brazing Connections 13 Flushing Line Set and Indoor Coil 16 Installing Indo...

Page 2: ...Hz J voltage Product Tier ML Merit Series Unit Type C Air Conditioner Cooling Stages 1 Single Stage Compressor Ratings Revision Level Nominal Cooling Capacity 036 3 tons 042 3 5 tons 048 4 tons 060 5...

Page 3: ...diameter in 5 16 5 16 5 16 5 16 No of rows 2 2 2 2 Fins per inch 22 22 22 22 Outdoor Fan Diameter in 22 22 22 26 No of Blades 3 3 4 4 Motor hp 1 6 1 6 1 4 1 4 Cfm 3160 3050 3600 4550 Rpm 825 825 825 8...

Page 4: ...CONNECTION 6 3 8 162 TOP VIEW BASE SECTION COMPRESSOR COIL DRAIN OUTLETS Around perimeter of base OPTIONAL UNIT STAND OFF KIT 4 Field Installed 111 4 3 8 4 3 8 4 3 8 4 3 8 6 3 8 162 111 111 111 111 4...

Page 5: ...CTION LINE SERVICE VALVE FIELD CONNECTION FOR SUCTION LINE HIGH PRESSURE SWITCH S4 COMPRESSOR HARNESS TYPICAL PLUMBING COPELAND COMPRESSOR TYPICAL PLUMBING LG COMPRESSOR HIGH PRESSURE SWITCH S4 FIELD...

Page 6: ...p before tightening TABLE 1 Torque Requirements Parts Recommended Torque Service valve cap 8 ft lb 11 NM Sheet metal screws 16 ft lb 2 NM Machine screws 10 28 ft lb 3 NM Compressor bolts 90 in lb 10 N...

Page 7: ...7 8 9 10 11 12 1 12 TURN 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...

Page 8: ...ions If unit coil cannot be mounted away from prevailing winter winds a wind barrier should be con structed Size barrier at least the same height and width as outdoor unit Mount barrier 24 inches 610...

Page 9: ...or 2 inches per 5 feet 50 mm per 1 5 m away from building structure DETAIL A DETAIL B INSTALL UNIT AWAY FROM WINDOWS TWO 90 ELBOWS INSTALLED IN LINE SET WILL REDUCE LINE SET VIBRATION GROUND LEVEL MOU...

Page 10: ...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 Repeat steps 1 2 and 3 to remove panels B C and D STEP 1 Startin...

Page 11: ...ING 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 exp...

Page 12: ...be used if line set is to be installed on exterior of outside wall PVC PIPE FIBERGLASS INSULATION CAULK OUTSIDE WALL VAPOR LINE WRAPPED WITH ARMAFLEX LIQUID LINE OUTSIDE WALL LIQUID LINE VAPOR LINE WO...

Page 13: ...T Allow braze joint to cool before removing the wet rag from the service valve Temperatures above 250 F can damage valve seals IMPORTANT Use silver alloy brazing rods with 5 minimum silver alloy for c...

Page 14: ...EN HIGH LOW B A C PIPING PANEL REMOVAL AND LINE SET PREPARATION CAP AND CORE REMOVAL Remove piping panel for easier access to service valves Cut ends of the refrigerant lines square free from nicks or...

Page 15: ...T TO SERVICE VALVES POINT FLAME AWAY FROM SERVICE VALVE PREPARATION FOR NEXT STEP 7 WRAP SERVICE VALVES To help protect service valve seals during brazing wrap water saturated cloths around service va...

Page 16: ...STING INDOOR UNIT GAUGE MANIFOLD INVERTED CYLINDER CONTAINS CLEAN HCFC22 TO BE USED FOR FLUSHING LIQUID LINE SERVICE VALVE INLET DISCHARGE TANK RETURN CLOSED OPENED RECOVERY CYLINDER RECOVERY MACHINE...

Page 17: ...Lightly lubricate connector threads and expose surface of the Teflon ring with refrigerantoil E Attach the liquid line assembly to the expansion valve Finger tighten and use an appropriately sized wre...

Page 18: ...KP SURE CLOSE THE VALVE ON THE HFC 410A CYLINDER AND THE VALVE ON THE HIGH PRESSURE SIDE OF THE MANIFOLD GAUGE SET DISCONNECT THE HFC 410A CYLINDER C CONNECT A CYLINDER OF DRY NITROGEN WITH A PRESSURE...

Page 19: ...r 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...

Page 20: ...rams 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 co...

Page 21: ...CONTROL WIRING NOTE Wire tie provides low voltage control wire strain relief and to maintain separation of field installed low and high voltage circuits NOTE For proper voltages select thermostat wire...

Page 22: ...Page 22 FIGURE 15 Typical Factory Wiring G and Y Voltages...

Page 23: ...Page 23 FIGURE 16 Typical Factory Wiring J Voltage...

Page 24: ...he technician to check the following items These checks may only be con ducted by a licensed professional HVAC technician Outdoor Unit 1 Inspect component wiring for loose worn or damaged connections...

Page 25: ...technician will check the refrigerant charge per the charging sticker information on the outdoor unit 3 Verify that system total static pressure and airflow set tings are within specific operating par...

Page 26: ...high pressure switch is closed 3 K1 1 N O closes energizing compressor B1 and out door fan motor B4 4 Compressor B1 and outdoor fan motor B4 begin im mediate operation END OF COOLING DEMAND 5 Cooling...

Page 27: ...the unit is running Power must be within range shown on the nameplate 8 Check system for sufficient refrigerant by using the procedures that follow System Refrigerant This section outlines procedures...

Page 28: ...DRY BULB A AND WET BULB B DT IS THE INTERSECTING VALUE OF A AND B IN THE TABLE SEE TRIANGLE 2 FIND TEMPERATURE DROP ACROSS COIL MEASURE ING THE COIL A AND C TEMPERATURE DROP FORMULA TDROP A MINUS C F...

Page 29: ...ve refrigerant based upon line length BLOCK OUTDOOR COIL sometimes necessary with lower temperatures Use cardboard or plastic sheet to restrict the airflow through the outdoor coil to achieve pressure...

Page 30: ...26 9 80 26 7 235 15 26 1 31 7 85 29 4 254 10 23 3 36 8 90 32 2 274 5 20 6 42 5 95 35 0 295 0 17 8 48 6 100 37 8 317 5 15 0 55 2 105 40 6 340 10 12 2 62 3 110 43 3 365 15 9 4 70 0 115 46 1 391 20 6 7...

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