Lennox ML180UH070E36A - User Manual

Page 1
UNIT INFORMATIONUNIT INFORMATION
Service Literature
©2016 Lennox Industries, Inc.
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.
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.
ML180UHE(X) series units are mid-e󰀩ciency gas furnac-
es used for upow or horizontal applications only, man-
ufactured with Lennox Duralok heat exchangers formed
of aluminized steel. ML180UHE(X) units are available in
heating capacities of 44,000 to 132,000 Btuh and cooling
applications 2 to 5 tons. Refer to Engineering Handbook
for proper sizing.
Units are factory equipped for use with natural gas. Kits
are available for conversion to LP/Propane operation.
ML180UHE(X) model units are equipped with a hot sur-
face ignition system. The ML180UHE(X) unit meets the
California Nitrogen Oxides (NOx) Standards and Califor-
nia Seasonal E󰀩ciency requirements.
All units use a redundant gas valve to assure safety shut-
o󰀨 as required by C.S.A. All specications in this manual
are subject to change. Procedures outlined in this manual
are presented as a recommendation only and do not su-
persede or replace local or state codes. In the absence
of local or state codes, the guidelines and procedures
outlined in this manual (except where noted) are recom-
mended only and do not constitute code.
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.
TABLE OF CONTENTS
Specications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
Blower Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4
Parts Identication . . . . . . . . . . . . . . . . . . . . . . . . . Page 6
I Unit Components . . . . . . . . . . . . . . . . . . . . . . . . Page 7
II Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 21
III Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 21
IV Heating System Service Checks . . . . . . . . . Page 21
V Typical Operating Characteristics . . . . . . . . . Page 26
VI Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 26
VII Wiring and Sequence of Operation . . . . . . Page 29
ML180UHE(X)
Corp 1120-L4
Revised 10-2017
ML180UHE(X) SERIES UNITS

Lennox ML180UH070E36A Specifications

General

Brand	Lennox
Model	ML180UH070E36A
Category	Furnace
Efficiency Rating	80%
AFUE	80%
Blower Motor	Multi-speed
Stages	Single-stage
Heat Exchanger	Aluminized steel
Weight	130 lbs
Fuel Type	Natural gas or propane
Heating Capacity	70000 BTU
Input BTU	70, 000 BTU
Warranty	Limited lifetime warranty on heat exchanger, 5-year warranty on parts

Summary

Parts Arrangement

Unit Components

Integrated Control System

The main control unit managing furnace operations and ignition.

Key Electrical Components

Transformer, interlock switch, and circuit breaker roles.

Heating Components

Flame Rollout Switches

High-temperature limit switches that stop ignition if flame rolls out.

Primary Limit Control

Over-temperature limit that opens if the heat exchanger overheats.

Flame Sensor

Detects flame presence to keep the gas valve open during operation.

Ignitor Checks

Combustion Air Inducer Pressure Switch

Blower Motor

Replacing the Motor Module

Installation, Start-Up, and Service Checks

Installation and Start-Up Procedures

Guidelines for unit installation and initiating heating operation.

Gas System and Combustion Checks

Verifying gas piping, pressure, and combustion performance.

Electrical and Grounding Checks

Verifying voltage, grounding, and control system power.

Typical Operating Characteristics

Blower Operation and Adjustment

How the blower operates and how to adjust its speed and timing.

Static Pressure and Temperature Rise

Measuring static pressure and temperature rise across the unit.

Maintenance

Wiring and Sequence of Operation

Schematic Wiring Diagram

Electrical diagram illustrating connections between components.

Heating Sequence of Operation

Detailed steps of how the furnace initiates and runs a heating cycle.

Cooling Sequence of Operation

Detailed steps of how the furnace operates during a cooling cycle.