Lennox Merit ML17XC1-018-230A 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 ML17XC1-018-230A Specifications

General

Type	Split System Air Conditioner
Cooling Capacity	1.5 Ton
Cooling Capacity (BTU)	18000 BTU
SEER Rating	17
Refrigerant	R-410A
Stages	1
Phase	1
Voltage	230V
Operating Temperature Range (Cooling)	Up to 115°F

Summary

Installation Instructions and General Information

Critical Safety Warnings

Highlights essential safety warnings regarding installation, service, and maintenance.

Handling Precautions

Advises on precautions to take when handling equipment with sharp edges.

Unit Setting and Clearances

Details the required clearances for the proper installation and placement of the unit.

Unit Placement and Refrigerant Piping Preparation

Electrical Safety Before Service

Safety caution to turn off electrical power before performing any service or maintenance.

Panel Handling and Structure Protection

Warning to prevent injury and damage from panels, especially in windy conditions.

Flushing Existing Refrigerant Lines

Initiates the process for flushing existing refrigerant lines and indoor coils.

Refrigerant Handling Safety

Safety warning regarding the inhalation hazards of refrigerant and the need for responsible use.

Refrigerant Piping and Brazing Procedures

Mineral Oil and POE Oil Compatibility

Explains the importance of flushing systems with mineral oil due to POE oil incompatibility.

Nitrogen Pressurization Safety

Warning about using nitrogen for pressurization and the need for appropriate regulators.

Moisture Sensitivity of POE Oils

Caution regarding POE oils absorbing moisture and the need to keep the system sealed.

Liquid Line Filter Drier Installation

Instructions for installing the liquid line filter drier to ensure a clean, moisture-free system.

Metering Device and Flushing Procedures

Connecting Gauges for Flushing

Line Set Flushing Procedure

Detailed steps for flushing the refrigerant line set and indoor unit coil with HCFC-22.

Brazing Refrigerant Lines

Manifold Gauge Set Connection for Brazing

Brazing Health and Safety Precautions

Cautionary notes on health hazards from brazing materials and preventing fire during brazing.

Brazing Procedures and Protections

Nitrogen Flow During Brazing

Brazing the Line Set

Instructions for brazing the refrigerant line set to the service valves.

Cooling Brazed Joints

Leak Testing and System Evacuation

Connecting Gauge Set for Leak Test

Procedure for Testing Leaks

Detailed steps to test the connected line set and indoor unit for leaks using HFC-410A and nitrogen.

System Evacuation Procedures

Connecting Gauge Set for Evacuation

Evacuating the Refrigerant System

Detailed steps for evacuating the line set and indoor unit to the required micron level.

Deep Vacuum Operation Warning

Warning about potential equipment damage and compressor failure from deep vacuum operation.

Electrical Wiring and Connections

Electrical Safety and Wire Type Warnings

Warnings about aluminum wire fire hazard, circuit sizing, and electric shock.

Electrostatic Discharge (ESD) Precautions

Precautions to protect electronic controls from electrostatic discharge during installation.

Circuit Sizing and Disconnect Switch

Thermostat Installation Guidelines

Unit Start-Up and Service Valve Operation

Manifold Gauge Set Usage

Service Port Access and System Charge

Checking and Adding System Charge

Guidance on checking and adding refrigerant charge based on line set length.

Maintenance, Cleaning, and System Testing

Professional Maintenance Guidelines

Aluminum Coil Cleaning Precautions

General System Performance Test

Steps for conducting a general system test to verify operating functions and temperatures.

Unit Start-Up and Performance Checklist

Start-Up Checks Summary

Subcooling Calculation Method

Approach Temperature Calculation Method

Indoor Coil Temperature Drop Measurement