Lennox Merit 14ACX−018−230 Installation Instructions Manual
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Lennox Merit 14ACX−018−230 Installation Instructions Manual

Merit series 14acx units
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E2011 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.
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
UNIT PLACEMENT
It is critical for proper unit operation to place outdoor unit on an
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
*2P0711*
INSTALLATION
INSTRUCTIONS
®
Merit
Series 14ACX Units
CONDENSING UNITS
506645−01
07/11
Supersedes 11/10

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Shipping and Packing List

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

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:
S
Thermal expansion valve (TXV)
S
Fixed orifice
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*P506645-01*
Litho U.S.A.
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Summary of Contents for Lennox Merit 14ACX−018−230

  • Page 1: Table Of Contents

    Unit Placement section on page 7. refrigerant. This outdoor unit must be installed with a matching indoor unit and line set as outlined in the Lennox 14ACX Engineering Handbook. BRAZING LINE SET TO SERVICE VALVES...

  • Page 2: Unit Dimensions

    Unit Dimensions − Inches (mm) DISCHARGE AIR OUTDOOR COIL FAN COMPRESSOR SUCTION AND LIQUID LINE CONNECTION OPTIONAL UNIT STANDOFF KIT (4) (FIELD INSTALLED) SIDE VIEW SIDE VIEW Model Numbers 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...

  • Page 3: Typical Unit Parts Arrangement

    Typical Unit Parts Arrangement NOTE Plumbing layout and compressor type may vary between model sizes. CONTROL THERMAL SWITCH COMPRESS0R (B1) DUAL RUN (S173) (−036 AND CAPACITOR −060 ONLY) (C12) GROUND LUG DISCHARGE LINE COMPRESSOR HARNESS CONNECTION CONTACTOR (K1) OUTDOOR COIL CUTOUT FOR HIGH VOLTAGE CONDUIT CONTROL WIRE...

  • Page 4: Operating Manifold Gauge Set And Service Valves

    Each valve is equipped with a service port which has a recess. factory−installed valve stem. Figure 2 provides information See the Lennox Service and Application Notes #C−08−1 on how to access and operating both angle and ball service for further details and information.
  • Page 5 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...

  • Page 6: Recovering Refrigerant From Existing System

    Recovering Refrigerant from Existing System Use the following procedure to recover refrigerant from an existing system (indoor coil, line set and outdoor unit). CONNECT MANIFOLD GAUGE SET DISCONNECT POWER Disconnect all power to the existing outdoor unit at the service Connect a gauge set, clean recovery cylinder and a recovery disconnect switch or main fuse box/breaker panel.

  • Page 7: New Unit Placement

    MINIMUM CLEARANCE CLEARANCE ON ALL SIDES INCHES (MILLIMETERS) ABOVE UNIT 6 (152) ACCESS PANEL NOTES: 48 (1219) Clearance to one of the other three sides must be 36 inches (914mm). 30 (762) 12 (305) Clearance to one of the remaining two sides may be 12 inches (305mm) and the final side may be 6 inches (152mm).

  • Page 8: Removing And Installing Louvers

    PLACING UNIT ON SLAB NOTICE When installing unit at grade level, the top of the slab should be high enough above grade so that water from Roof Damage! higher ground will not collect around the unit. The slab should have a slope tolerance as described in figure 5, This system contains both refrigerant and oil.

  • Page 9: New Or Replacement Line Set

    Typically a liquid line used to meter flow is 1/4" in diameter Lennox Technical Support Product Applications for and copper. assistance. To obtain the correct information from Lennox, be sure to LIQUID LINE FILTER DRIER INSTALLATION communicate the following points: The filter drier (one is shipped with each 14ACX unit) must Model (14ACX) and size of unit (e.g.
  • Page 10 LINE SET IMPORTANT Refrigerant lines must not contact structure. INSTALLATION REFRIGERANT LINE SET INSTALLING Line Set Isolation The following illustrations are VERTICAL RUNS (NEW CONSTRUCTION SHOWN) examples of proper refrigerant line set isolation: NOTE Insulate liquid line when it is routed through areas where the surrounding ambient temperature could become higher than the REFRIGERANT LINE SET TRANSITION...

  • Page 11: Brazing Connections

    Brazing Connections IMPORTANT Use the procedures outline in figures 9 and 10 for brazing line set connections to service valves. Connect gauge set low pressure side to vapor line service valve and repeat procedure starting at IMPORTANT paragraph 4 for brazing the liquid line to service port valve.
  • Page 12 CAP AND CORE REMOVAL CUT AND DEBUR Cut ends of the refrigerant lines square (free from nicks or dents) Remove service cap and core from and debur the ends. The pipe must remain round. Do not crimp end both the suction / vapor and liquid line of the line.
  • Page 13 WRAP SERVICE VALVES To help protect service valve seals during brazing, wrap water saturated cloths around service valve bodies and copper tube stubs. Use additional water saturated cloths underneath the valve body to protect the base paint. FLOW NITROGEN Flow regulated nitrogen (at 1 to 2 psig) through the refrigeration gauge set into the valve stem port connection on the liquid service valve and out of the suction / vapor valve stem port.

  • Page 14: Flushing Line Set And Indoor Coil

    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. TYPICAL EXISTING FIXED ORIFICE TYPICAL EXISTING EXPANSION VALVE REMOVAL REMOVAL PROCEDURE (UNCASED PROCEDURE (UNCASED COIL SHOWN) COIL SHOWN)

  • Page 15: Installing Indoor Metering Device

    Refer to below illustration for reference during installation of expansion valve unit. . See the Lennox 14ACX Engineering Handbook for After installation of the indoor coil metering device, approved expansion valve kit match ups. The expansion valve unit can be installed internal or external to the indoor proceed to Leak Test Line Set and Indoor Coil on page 16.

  • Page 16: Leak Test Line Set And Indoor Coil

    Take down to 1 or 2 psig (6.9 to 13.8 kPa). care to empty all existing traps. Polyol ester (POE) oils are used in Lennox units charged with HFC−410A WARNING refrigerant. Residual mineral oil can act as an insulator, preventing proper heat transfer.

  • Page 17: Evacuating Line Set And Indoor Coil

    Evacuating Line Set and Indoor Coil CONNECT GAUGE SET HIGH NOTE Remove cores from service valves (if not already done). Connect low side of manifold gauge set with 1/4 SAE in−line tee to vapor line service valve Connect high side of manifold gauge OUTDOOR set to liquid line service valve MANIFOLD...

  • Page 18: Electrical Connections

    defined as any gas that will not condense under WARNING temperatures and pressures present during operation of an air conditioning system. Non−condensables and water Danger of Equipment Damage. Avoid deep vacuum suction combine with refrigerant to produce substances operation. Do not use compressors to evacuate a that corrode copper piping and compressor parts.
  • Page 19 ROUTING HIGH VOLTAGE/ GROUND AND CONTROL WIRING SINGLE PHASE HIGH VOLTAGE HIGH VOLTAGE / GROUND WIRES CONNECTIONS Any excess high voltage field wiring should be trimmed and (CONTACTOR) CONTROL secured away from any low voltage field wiring. To facilitate a WIRING conduit, a cutout is located in the bottom of the control panel.
  • Page 20 HIGH PRESSURE SWITCH (S4) LIQUID LINE CRANKCASE HEATER (HR1) CRANKCASE THERMOSTAT (S40) Figure 16. Typical Factory Wiring Diagram (Copeland Compressor) Page 20 506645−01...
  • Page 21 THERMAL PROTECTION SWITCH (S5 OR S173) HIGH PRESSURE SWITCH (S4) LIQUID LINE CRANKCASE HEATER (HR1) CRANKCASE THERMOSTAT (S40) Figure 17. Typical Factory Wiring Diagram (Interlink Compressor) Page 21 14ACX SERIES...

  • Page 22: Servicing Unit Delivered Void Of Charge

    2. Inspect all factory− and field−installed wiring for loose Servicing Units Delivered Void of Charge connections. If the outdoor unit is void of refrigerant, clean the system 3. After evacuation is complete, open the liquid line and using the procedure described below. suction line service valve stems (Operating Service Valves on page 4) to release the refrigerant charge 1.
  • Page 23 CHECKING AIR FLOW AT INDOOR COIL Check airflow using the Delta−T ( process using the illustration in figure 19. 1. Determine the desired DT Measure entering air temper- Temp. 24 24 24 23 23 22 22 22 20 19 18 17 16 15 ature using dry bulb (A) and wet bulb (B).
  • Page 24 WEIGH IN (RFC AND TXV) CALCULATING SYSTEM CHARGE FOR OUTDOOR UNIT VOID OF CHARGE If the system is void of refrigerant, first, locate and repair any leaks and then weigh in the refrigerant charge into the unit. To calculate the total refrigerant charge: Adjust amount.
  • Page 25 65ºF (18.3ºC) 1. Confirm proper airflow across coil using figure 19. USE WEIGH-IN METHOD and above 2. Compare unit pressures with table 4, Normal Weigh-in or remove refrigerant Operating Pressures. based upon line length 3. Set thermostat to call for heat (must have a cooling load between 70-80ºF (21−26ºC) ABOVE or 64ºF (17.7ºC)
  • Page 26 1. Confirm proper airflow across coil using figure 19. START: Measure outdoor ambient temperature 39ºF 2. Compare unit pressures with table 4, Normal (3.8ºC) and Operating Pressures. Below 3. Use SUPERHEAT to correctly charge unit or to USE WEIGH-IN METHOD verify the charge is correct.
  • Page 27 Table 4. HFC−410A Normal Operating Pressures (Liquid +10 and Suction +5 psig) Use this table to perform maintenance checks; it is not a procedure for charging the system. Minor variations in these pressures may be due to differences in installations. IMPORTANT Significant deviations could mean that the system is not properly charged or that a problem exists with some component in the system.

  • Page 28: System Operation

    temperature falls to 151−187°F (66°C−86°C), and the System Operation compressor is re−energized. This single−pole, single−throw (SPST) bi−metallic switch is wired in series with the 24V Y UNIT COMPONENTS input signal to control compressor operation. Crankcase Heater (HR1) and Thermostat Switch IMPORTANT (S40) (−041 through −060 models only) These models are equipped with either a 40 or 70 watt...
  • Page 29 Refer to the unit information service manual for pressure drop tables and procedure. 1. Air Filter Ask your Lennox dealer to show you where your indoor unit’s filter is located. It will be either 4. Belt Drive Blowers − Check belt for wear and proper at the indoor unit (installed internal or external to the tension.

  • Page 30: Start−Up And Performance Checklist

    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...

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