Lennox 80UHG3-60 User Manual

Page 1
 1999 Lennox Industries Inc.
Litho U.S.A.
Corp. 9728−L12
80UHG
Service Literature
Revised 01−2002
80UHG series units are mid−efficiency gas furnaces used
for upflow or horizontal applications only, manufactured
with tubular heat exchangers formed of aluminized steel.
80UHG units are available in heating capacities of 45,000
to 120,000 Btuh and cooling applications up 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 LPG operation. 80UHG−1 model
units use electronic (direct spark) ignition. 80UHG−2 and −3
model units are equipped with the Lennox SureLight silicon
nitride ignition system. The 80UHGX unit meets the Califor
nia Nitrogen Oxides (NO
x
) Standards and California Sea
sonal Efficiency requirements. All units use a redundant gas
valve to assure safety shut−off as required by A.G.A. or
C.G.A. Units may be installed in upflow or horizontal posi
tion.
All specifications in this manual are subject to change. Pro
cedures outlined in this manual are presented as a recom
mendation only and do not supersede 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 recommended only and do not constitute
code.
TABLE OF CONTENTS
Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Data 3−4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
High Altitude 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Identification 5−6. . . . . . . . . . . . . . . . . . . . . . . . . . . .
I Unit Components 6−15. . . . . . . . . . . . . . . . . . . . . . . . . . .
II Installation 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
III Start Up 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV Heating System Service Checks 16−17. . . . . . . . . . .
V Typical Operating Characteristics 18. . . . . . . . . . . . . .
VI Maintenance 19−20. . . . . . . . . . . . . . . . . . . . . . . . . . . .
VII Wiring and Sequence of Operation 21−28. . . . . . . . .
VIII SureLight Troubleshooting Guide 29−34. . . . . . . . . .

Lennox 80UHG3-60 Specifications

General

Input BTU	60, 000
AFUE	80%
Blower Motor Type	PSC
Gas Valve Type	Single
Stages	Single Stage

Summary

UNIT INFORMATION

SPECIFICATIONS

BLOWER DATA

FILTER AIR RESISTANCE

HIGH ALTITUDE DERATE

80UHG PARTS IDENTIFICATION

UNIT COMPONENTS

ELECTROSTATIC DISCHARGE (ESD) Precautions and Procedures

Furnace Control (A3) 80UHG-2, -3 Models

SURELIGHT INTEGRATED CONTROL BOARD

SureLight Ignitor

Details about the SureLight Ignitor component and its specifications for the control board.

Flame Sensor

Information on the flame sensor component for 80UHG-2 models.

Furnace Control (A3) 80UHG-1 Model

Ignition Control

Description of the direct spark ignition control system for the 80UHG-1 model.

Safety Circuits

Details on the safety circuits monitored by the furnace control board.

Blower Operation / Fan Off Timings

Explanation of fan operation modes and adjustment of fan off timing.

Thermostat Connection

Troubleshooting

Blower Motors and Capacitors

Combustion Air Inducer

Flame Rollout Switches

Primary Limit Control

Secondary Limit Controls

Spark Electrode and Flame Sensor

Gas Valve

Combustion Air Blower Prove Switch

START-UP

Preliminary and Seasonal Checks

Pre-startup checks including electrical wiring and voltage verification.

Heating Start-Up

Procedure for starting the furnace for heating operation, including safety steps.

Turning Off Gas To Unit

Instructions for safely turning off the gas supply to the unit.

Safety or Emergency Shutdown

Procedure for shutting down the unit in case of safety or emergency.

Extended Period Shutdown

Guidelines for shutting down the unit for extended periods.

HEATING SYSTEM SERVICE CHECKS

A.G.A./C.G.A. Certification

Details on the unit's design certification standards.

Gas Piping

Requirements for gas supply piping installation and connection.

Testing Gas Piping

Procedures for testing gas piping for leaks and pressure integrity.

Testing Gas Supply Pressure

Method for testing and verifying gas supply pressure to the unit.

Check Manifold Pressure

Procedure for checking and verifying manifold gas pressure.

Proper Gas Flow (Approximate)

Measure Flame Signal - Ignition Control

Flame Signal

TYPICAL OPERATING CHARACTERISTICS

Blower Operation and Adjustment

General guidelines for blower operation and speed adjustment.

Temperature Rise

Procedure for measuring and setting the unit's temperature rise.

External Static Pressure

Method for measuring external static pressure in the duct system.

Blower Speed Taps Leadless Motors

Instructions for changing blower speed taps on leadless motors.

Blower Speed Taps Leaded Motors

MAINTENANCE

Filters

Guidance on checking, cleaning, or replacing air filters for proper operation.

Heat Exchanger and Burners

Procedures for inspecting and cleaning heat exchangers and burners.

Supply Air Blower

Flue and Chimney

Electrical

Wiring and Sequence of Operation

80UHG-1 MODEL WITH SURELIGHT CONTROL

Detailed wiring diagram and operational sequence for the 80UHG-1 model.

80UHG-1 HEATING SEQUENCE OF OPERATION

80UHG-1 COOLING SEQUENCE OF OPERATION

80UHG-1 MANUAL CONTINUOUS FAN SEQUENCE OF OPERATION

80UHG-2 MODEL WITH SURELIGHT CONTROL

HEATING SEQUENCE OF OPERATION

HEATING SEQUENCE CONTINUED

COOLING SEQUENCE OF OPERATION

SURELIGHT CONTROL CONTINUOUS HEAT SPEED FAN SEQUENCE OF OPERATION

Troubleshooting-SureLight Control

SURELIGHT - TROUBLE SHOOTING GUIDE

Comprehensive guide to diagnosing and resolving issues with the SureLight control.

Unit Fails to Operate

Troubleshooting steps for units failing to operate in cooling, heating, or fan modes.

Unit Fails to Operate (Cont.)

Unit Fails to Fire (No Inducer)

Unit Fails to Fire (No Inducer - Cont.)

Unit Fails to Fire (Inducer Energized, No Ignitor)

Unit Fails to Fire (Inducer Energized, Ignitor Energized)

Burners Light Prematurely Shut Down

Burners Light Prematurely Shut Down (Cont.)

Low Flame Sense

Indoor Blower Fails to Operate

RF Static During Ignition