Lennox Merit ML17XC1-042-230A User Manual

©2022 Lennox Industries Inc.
Dallas, Texas, USA
Page 1
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
General
This ML17XC1 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 han-
dler or coil. For AHRI Certied system match-ups and ex-
panded ratings, visit www.LennoxPros.com.
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
NOTICE!
Charging information is given on the charging
procedure sticker on the unit access panel. For more in-
depth information, consult the Installation and Service
Procedures manual on LennoxPros.com or through the
Technical Support department at 800-453-6669.
INSTALLATION
INSTRUCTIONS
AIR CONDITIONER
508254-01
4/2022
Merit
®
Series ML17XC1 Units
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, or service agency.
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.
IMPORTANT: Special procedures are required for clean-
ing the all-aluminum coil in this unit. See page 15 in this
instruction for information.
STEP 1 – SETTING THE UNIT – Clearances
NOTES -
Service clearance of 30 in. (762 mm) must be maintained on one of
the sides adjacent to the control box.
Clearance to one of the other three sides must be 36 in. (914 mm).
Clearance to one of the remaining two sides may be 12 in. (305
mm) and the final side may be 6 in. (152 mm).
A clearance of 24 in. must be maintained between two units.
48 in. (1219 mm) clearance required on top of unit.
See
NOTES
See NOTES
See NOTES
See
NOTES
CONTROL
BOX
NOTICE: Specific applications may require adjustment of the listed installation clearances to provide protection for
the unit from physical damage or to avoid conditions which limit operating efficiency. (Example: Clearances may
have to be increased to prevent snow or ice from falling on the top of the unit. Additional clearances may also be
required to prevent air recirculation when the unit is installed under a deck or in another tight space.)
FIGURE 1

Lennox Merit ML17XC1-042-230A Specifications

General

Cooling Capacity	3.5 Tons
Refrigerant	R-410A
Compressor Type	Single-Stage
Noise Level	74 dB
Voltage	230V
Type	Split System
SEER Rating	17
Stages	Single

Summary

Refrigerant Piping - Flushing

WARNING - Refrigerant Handling Safety

Warns about the dangers of inhaled refrigerant and responsible use.

Refrigerant Piping - Flushing and Components

Coil and Line Set Flushing Requirements

Details the necessity of flushing older systems due to mineral oil.

Refrigerant Oil and Moisture Sensitivity

Liquid Line Filter Drier Installation

Explains the filter drier's role and where to install it in the liquid line.

Refrigerant Piping - Metering Device and Flushing

Indoor Metering Device Removal Procedures

Provides step-by-step instructions for removing fixed orifice and expansion valves.

Flushing Procedure Setup and Execution

Refrigerant Piping - Brazing Procedures

Line Preparation for Brazing

Manifold Gauge Set Connection for Brazing

Guides on connecting manifold gauges for brazing with nitrogen flow.

Brazing Safety Warnings

Warns about brazing material hazards and fire risks during brazing.

Refrigerant Piping - Brazing Execution

Service Valve Protection and Nitrogen Flow

Instructs on protecting valves and flowing nitrogen during brazing.

Brazing Process and Joint Cooling

Details the brazing process, cooling joints, and safety precautions.

Refrigerant Piping - Indoor Expansion Valve Installation

Indoor Expansion Valve Installation Steps

Sensing Bulb and Equalizer Line Installation

Leak Test and Evacuation - Setup

Gauge Set Connection for Leak Testing

Leak Testing Procedure

Details the procedure for testing the system for leaks using nitrogen.

Leak Test and Evacuation - Process

Gauge Set Connection for Evacuation

System Evacuation Procedure

Details the step-by-step process for evacuating the system to the required vacuum level.

WARNING - Deep Vacuum Operation Hazard

Warns against deep vacuum operation and potential compressor damage.

Electrical - Circuit Sizing and Wiring

Electrical Safety Warnings

Covers shock, aluminum wire, ESD, and sizing hazards.

Circuit Sizing and Disconnect Switch

Electrical - Wiring Diagrams and Routing

High Voltage and Control Wiring Routing

24VAC Control Wiring Diagrams

Unit Start-Up Procedures

Pre-Start Up Checks and Valve Operation

Service Access and System Charge

System Charge Check and Adjustment

Details adjusting refrigerant charge based on piping length and component functions.

Start-Up and Performance Checklist

Unit Information and Start-Up Checks

Cooling Mode Performance Measurements

Areas to record suction/liquid pressures and air temperatures for performance assessment.

Performance Calculation Methods