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Lennox International Inc. Merit Series 14ACX Units - page 1
07/1 1 506645−01 *2P0711* *P506645-01* Page 1 201 1 Lennox Industries Inc. Dallas, T exas, USA RET AIN 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 inst allation. W ARNING Improper installation, adjustme ...
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Lennox International Inc. Merit Series 14ACX Units - page 2
Page 2 506645−01 Unit Dimensions − Inches (mm) SUCTION AND LIQUID LINE CONNECTION DISCHARGE AIR SIDE VIEW OUTDOOR COIL F AN COMPRESSOR A B A OPTIONAL UNIT ST ANDOFF KIT (4) (FIELD INST ALLED) 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 (72 ...
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Lennox International Inc. Merit Series 14ACX Units - page 3
Page 3 14ACX SERIES T ypical Unit Parts Arrangement COMPRESSOR HARNESS CONNECTION LIQUID LINE SERVICE V AL V E SUCTION LINE SERVICE V AL VE OUTDOOR COIL DISCHARGE LINE HIGH PRESSURE SWITCH (S4) COMPRESS0R (B1) GROUND LUG CONT ACT OR (K1) CONTROL DUAL RUN CAP ACIT OR (C12) CONTROL WIRE LOOP CUTOUT FOR HIGH VOL TAGE CONDUIT NOTE Plumbing layout a ...
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Lennox International Inc. Merit Series 14ACX Units - page 4
Page 4 506645−01 CAUTION Physical contact with metal edges and corners while applying excessive force or rapid motion can result in personal injury . Be aware of, and use caution when working near these areas during installation or while servicing this equipment. Operating Manifold Gauge Set and Service V alves These instructions are intended as ...
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Lennox International Inc. Merit Series 14ACX Units - page 5
Page 5 14ACX SERIES (V AL VE STEM SHOWN CLOSED) INSERT HEX WRENCH HERE SERVICE PORT CORE SER VICE PORT CAP ANGLE−TYPE SERVICE V AL VE (FRONT−SEA TED CLOSED) SER VICE PORT CORE TO OUTDOOR UNIT STEM CAP (V AL VE STEM SHOWN OPEN) INSER T HEX WRENCH HERE TO INDOOR UNIT ANGLE−TYPE SERVICE VALVE (BACK−SEATED OPENED) BALL (SHOWN CLOSED) SER VICE P ...
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Lennox International Inc. Merit Series 14ACX Units - page 6
Page 6 506645−01 Recovering Refrigerant from Existing System Use the following procedure to recover refrigerant from an existing system (indoor coil, line set and outdoor unit). SER VICE DISCONNECT SWITCH MAIN FUSE BOX/BREAKER P ANEL Disconnect all power to the existing outdoor unit at the service disconnect switch or main fuse box/breaker panel. ...
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Lennox International Inc. Merit Series 14ACX Units - page 7
Page 7 14ACX SERIES 6 (152) 36 (914) 12 (305) 30 (762) LINE SET CONNECTIONS 24 (610) LINE SET CONNECTIONS ACCESS P ANEL 48 (1219) MINIMUM CLEARANCE BETWEEN TWO UNITS CLEARANCE ON ALL SIDES INCHES (MILLIMETERS) ACCESS P ANEL MINIMUM CLEARANCE ABOVE UNIT NOTES: Clearance to on e of the o ther three sides must be 36 inches (914mm). Clearan ...
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Lennox International Inc. Merit Series 14ACX Units - page 8
Page 8 506645−01 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 su ...
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Lennox International Inc. Merit Series 14ACX Units - page 9
Page 9 14ACX SERIES 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 p age 1 1. Field refrigerant piping consist s of liquid and suction lines from the out door un it (braze connections) to t ...
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Lennox International Inc. Merit Series 14ACX Units - page 10
Page 10 506645−01 ANCHORED H EA VY NYLON WIRE TIE OR AUT OMOTIVE MUFFLER-TYPE HANGER STRAP LIQUID LINE TO V APOR LINE W ALL STUD LIQUID LINE NON−CORROSIVE MET AL SLEEVE V APOR LINE − WRAPPED IN ARMAFLEX AUT OMOTIVE MUFFLER-TYPE HANGER REFRIGERANT LINE SET TRANSITION FROM VERTICAL TO HORIZONT AL Line Set Isolation The following illustr ...
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Lennox International Inc. Merit Series 14ACX Units - page 11
Page 1 1 14ACX SERIES Brazing Connections Use the procedures outline in figures 9 and 1 0 for brazing line set connections to service valves. IMPORT ANT Polyol ester (POE) oils used wit h HFC−410A refr igerant absorb moisture very quickly . It is very important that the refrigerant sys tem be kept closed as much as possible. DO NOT remove li ne s ...
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Lennox International Inc. Merit Series 14ACX Units - page 12
Page 12 506645−01 A TT ACH THE MANIFOLD GAUGE SET FOR BRAZING LIQUID AND SUCTION / V APOR LINE SER VICE V AL VES OUTDOOR UNIT LIQUID LINE V APOR LINE LIQUID LINE SERVICE VA LV E SUCTION / V APOR LINE SER VICE VA LV E A TTACH GAUGES INDOOR UNIT SUCTION / V APOR SER VICE POR T MUST BE OPEN TO ALLOW EXIT POINT FOR NITROGEN A Connect gauge set low pr ...
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Lennox International Inc. Merit Series 14ACX Units - page 13
Page 13 14ACX SERIES WHEN BRAZING LINE SET TO SER VICE V AL VES, POINT FLAME A W A Y FROM SER VICE V A L VE. LIQUID LINE SERVICE V AL VE LIQUID LINE BRAZE LINE SET W rap both service valves with water saturated cloths as illustrated here and as mentioned in step 4, before brazing to line set . W ater saturated cloths must remain water saturated thr ...
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Lennox International Inc. Merit Series 14ACX Units - page 14
Page 14 506645−01 Flushing Line Set and Indoor Coil Flushing is only required if existing indoor coil and line set are to be used. Otherwise proceed to Installing Indoor Metering Device on page 15 . SENSING LINE TEFLON ® RING FIXED ORIFICE BRASS NUT LIQUID LINE ASSEMBL Y (INCLUDES STRAINER) LIQUID LINE ORIFICE HOUSING DISTRIBUT OR TUBES DISTRIBU ...
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Lennox International Inc. Merit Series 14ACX Units - page 15
Page 15 14ACX SERIES Installing Indoor Metering Device This outdoor unit is designed for use in systems that use either an fixed orifice (RFC) (included with outdoor unit), or exp ansion valve metering device (purchased sep arately) at the indoor coil. See the Lennox 14ACX Engineering Handbook for approved e x pansion valve kit matc h u ps. The exp ...
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Lennox International Inc. Merit Series 14ACX Units - page 16
Page 16 506645−01 IMPORT ANT The Environmental Protection Agency (EP A) prohibits the intentional venting of HFC refrigerants during maintenance, service, repair and disposal of appliance. Approved methods of recovery , recycling or reclaiming must be followed. IMPORT ANT If this unit is being matc hed with an approved line set or indoor unit coi ...
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Lennox International Inc. Merit Series 14ACX Units - page 17
Page 17 14ACX SERIES Evacuating Line Set and Indoor Coil 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 ...
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Lennox International Inc. Merit Series 14ACX Units - page 18
Page 18 506645−01 W ARNING Danger of Equipm ent Damage. A void deep vacuum operation. Do not use compressors to evacuate a system. Extremely low vacuums can cause internal arcing and compress or failure. Damage caused by deep vacuum operat ion will void warranty . CAUTION Brazing alloys and flux cont ain materials which are hazardous to your heal ...
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Lennox International Inc. Merit Series 14ACX Units - page 19
Page 19 14ACX SERIES Any excess high voltage field wiring should be trimmed and secured away from any low voltage field wiring. T o facilitate a conduit, a cutout is located in the bottom of the control panel. Connect conduit to the control panel using a proper conduit fitting. ROUTING HIGH VOL T AGE/ GROUND AND CONTROL WIRING HIGH VOL T AGE FIELD ...
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Lennox International Inc. Merit Series 14ACX Units - page 20
Page 20 506645−01 HIGH PRESSURE SWITCH (S4) LIQUID LINE CRANKCASE THERMOST A T (S40) CRANKCASE HEA TER (HR1) Figure 16. T ypical Factory Wiring Diagram (Copeland Compressor) ...
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Lennox International Inc. Merit Series 14ACX Units - page 21
Page 21 14ACX SERIES CRANKCASE HEA TER (HR1) HIGH PRESSURE SWITCH (S4) LIQUID LINE CRANKCASE THERMOST A T (S40) THERMAL PROTECTION SWITCH (S5 OR S173) Figure 17. T ypical Factory Wiring Diagram (Interlink Compressor) ...
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Lennox International Inc. Merit Series 14ACX Units - page 22
Page 22 506645−01 Servicing Units Delivered V oid of Charge If the out door unit is void of refrigerant, clean the system using the procedure described below . 1. Leak check system using procedure outlined in this instruction. 2. Evacuate the system using procedure outlined in this instruction. 3. Use nitrogen to break the vacuum and install a ne ...
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Lennox International Inc. Merit Series 14ACX Units - page 23
Page 23 14ACX SERIES CHECKING AIR FLOW A T INDOOR COIL Check airflow using the Delta−T ( D T) process using the illustration in figure 19. 1. Determine the desired D T Measure entering air temper- ature using dry bulb ( A ) and wet bulb ( B ). D T is the intersect- ing value of A and B in the t able (see triangle). 2. Find temperature drop acr ...
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Lennox International Inc. Merit Series 14ACX Units - page 24
Page 24 506645−01 Liquid Line Set Diameter Ounces per 5 feet (g per 1.5 m) adjust from 15 feet (4.6 m) line set* 3/8" (9.5 mm) 3 ounce per 5’ (85 g per 1.5 m) *If line length is greater than 15 ft. (4.6 m), add this amount. If line length is less than 15 ft. (4.6 m), subtract this amount. Refrigerant Charge per Line Set Length NOTE The ...
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Lennox International Inc. Merit Series 14ACX Units - page 25
Page 25 14ACX SERIES 1. Confirm proper airflow across coil using figure 19. 2. Compare unit pressures with table 4, Normal Operating Pressures . USE WEIGH-IN METHOD Weigh-in or remove refrigerant based upon line length SCº (Subcooling) V alues (F:+/−1.0° [C: +/−0.6°]) BLOCK OUTDOOR COIL: [sometimes necessary with lower temperatures] Use card ...
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Lennox International Inc. Merit Series 14ACX Units - page 26
Page 26 506645−01 ST ART : Measure outdoor ambient temperature NOTE − Do not attempt to charge system where a dash appears, system could be overcharged. Superheat is taken at suction line service port. Suction line superheat must never be less than 5ºF at the suction line service port. USE WEIGH-IN METHOD Weigh-in or remove refrigerant based u ...
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Lennox International Inc. Merit Series 14ACX Units - page 27
Page 27 14ACX SERIES T able 4. HFC−410A Normal Operating Pressures (Liquid +10 and Suction +5 psig) IMPORT ANT Use this t able to perform maintenance checks; it is not a procedur e for charging the system. Minor variations in these pressures may be due to differences in instal lations. Significant deviations could mean that the sy stem is not pro ...
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Lennox International Inc. Merit Series 14ACX Units - page 28
Page 28 506645−01 System Operation UNIT COMPONENTS IMPORT ANT Some scroll compressor have internal vacuum protector that will unload scrolls when suction pressure 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 COMPR ...
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Lennox International Inc. Merit Series 14ACX Units - page 29
Page 29 14ACX SERIES Indoor Unit 1. Clean or change filters. 2 . Lennox blower mot ors are prelubricat ed and permanent ly sealed. No more lubr ication is needed. 3 . Adjust blower speed for cooling. Meas ure the pressure drop over the coil to determ ine the corr ect blower CFM. Refer t o the u nit i nfor mat ion s ervic e manual f or p ressur e dr ...
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Lennox International Inc. Merit Series 14ACX Units - page 30
Page 30 506645−01 S tart−Up and Performance Checklist Job Name Job no. Date Job Location City S tate Installer City S tate Unit Model No. Serial No. Service T echnician Nameplate V olt age Rated Load Ampacity Compressor Outdoor Fan Maximum Fuse or Circuit Breaker Electrical Connections T ight? Indoor Filter clean? Supply V olt age (Unit ...
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