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Lennox G60UH - User Manual

Lennox G60UH
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Page 1
© 2002 Lennox Industries Inc.
Corp. 0204−L2
Revised 11−2006
G60UH(X)
Service Literature
G60UH(X) SERIES UNITS
G60UH(X) series units are mid−efficiency gas furnaces
used for upflow or horizontal applications only, manufac-
tured with Lennox Duralok Plus heat exchangers formed of
aluminized steel. G60UH(X) units are available in heating
capacities of 44,000 to 132,000 Btuh and cooling applica-
tions up to 5 tons. Refer to Engineering Handbook for prop-
er sizing.
Units are factory equipped for use with natural gas. Kits are
available for conversion to LPG operation. G60UH(X) model
units are equipped with the Two−Stage / Variable Speed Inte-
grated SureLight control. G60UH(X) 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 C.S.A.
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 recommendations only and do not consti-
tute code.
TABLE OF CONTENTS
Specifications Page 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Data Page 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
High Altitude Page 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Identification Page 11. . . . . . . . . . . . . . . . . . . . . . . .
I Unit Components Page 12. . . . . . . . . . . . . . . . . . . . . . .
II Installation Page 24. . . . . . . . . . . . . . . . . . . . . . . . . . . .
III Start Up Page 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV Heating System Service Checks Page 25. . . . . . . . .
V Typical Operating Characteristics Page 27. . . . . . . . .
VI Maintenance Page 28. . . . . . . . . . . . . . . . . . . . . . . . . .
VII Wiring and Sequence of Operation Page 30. . . . . .
VIII Field Wiring and Jumper Setting Page 46. . . . . . . .
IX Control Board Troubleshooting Page 50. . . . . . . . . .
G60UH−1 MODEL SHOWN
IMPORTANT
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a qualified installer, service agency
or the gas supplier.
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at discon-
nect switch(es). Unit may have multiple
power supplies.
WARNING
Sharp edges.
Be careful when servicing unit to avoid sharp edges
which may result in personal injury.

Questions and Answers

  • B
    Brianna JohnsonAug 14, 2025
    How to fix Lennox G60UH Furnace that fails to operate?
    • S
      Susan PattersonAug 14, 2025
      If your Lennox furnace isn't working in cooling, heating, or continuous fan mode, here's what you can check: * Ensure the unit is getting 120V main voltage. If not, determine the cause of the power failure. * Inspect the wiring to the power make up box and transformer for correct connections, as well as the 24V wiring to the control board. * Check the circuit breaker. If it trips again after being reset, look for a short circuit. * Make sure the door switch is activated when the door is closed. Check the wire connections to the switch and the continuity of the switch in the closed position. * Verify that the transformer output is 24V. Replace it if it's defective. * If all the above items have been checked, replace the control board.
  • P
    Patricia GilesAug 20, 2025
    What to do if Lennox Furnace indoor blower fails to operate?
    • S
      Susan FullerAug 20, 2025
      If the indoor blower in your Lennox furnace isn't working in cooling, heating, or continuous fan mode, consider the following: * Check the wiring at the control and indoor blower motor for any miswiring or loose connections. Correct any issues found. * Confirm that 120V is being supplied to the indoor air blower by energizing "Y", "G", and "W" individually on the low voltage terminal strip. Remember that when "W" is energized, the blower has a 45-second delay. If there is 120V to each motor tap but the blower doesn't operate, replace the motor. * If there is not 120V when "Y", "G", or "W" is energized, replace the control board. * Replace the run capacitor if it is defective.
  • D
    Douglas DouglasSep 2, 2025
    What causes a Lennox Furnace to fail to fire if the combustion air inducer doesn't energize?
    • C
      cardenasjenniferSep 3, 2025
      If your Lennox furnace fails to fire in heating mode, and the combustion air inducer doesn't energize, consider these potential causes: * Check for correct wiring and loose connections to the combustion air inducer. Correct wiring and/or replace any loose connections. * If there's 120V to the combustion air inducer, and it still doesn't operate, replace the combustion air inducer.
  • P
    Paula MillerSep 9, 2025
    How to fix Lennox G60UH Furnace showing low flame sense?
    • Z
      Zachary TurnerSep 10, 2025
      If your Lennox furnace control signals a low flame sense during heating mode: * Check the sense rod for proper location on the burner. Properly locate the sense rod or replace it if it cannot be located correctly. * Check the sense rod for contamination or a coated surface. Clean the sense rod with steel wool or replace the sensor. Do not use sandpaper to clean the rod, as this will contribute to the contamination problem.
  • M
    Mark TateNov 16, 2025
    How to troubleshoot Lennox G60UH when ignitor is not energized?
    • J
      Joseph CaseyNov 16, 2025
      If your Lennox furnace fails to fire in heating mode, the combustion air blower energizes, but the ignitor doesn't, here's how to troubleshoot: * Check if the pressure switch line is correctly routed. Correct its routing if necessary. * Ensure there are no obstructions in the pressure switch line and/or taps. Remove any obstructions. * Inspect the pressure switch line for leaks and replace it if damaged. * Check for condensate in the pressure switch line and remove it. * Verify the differential pressure across the pressure switch. It should exceed the set point listed on the switch. Check for a restricted inlet vent and remove any blockage. Ensure proper vent sizing and run length. * Confirm the proper pressure switch is installed in the unit. Replace it if necessary. * Chec...
  • J
    Jill RoblesNov 23, 2025
    Why does my Lennox G60UH shut down prematurely?
    • G
      gonzalezkatherineNov 23, 2025
      If your Lennox furnace burners light with a heating demand but the unit shuts down prematurely, consider these potential causes: * Low pressure differential at the pressure switch. Check for a restricted exhaust vent and remove any blockages. Ensure proper vent sizing. * Improperly installed sensor or sense wire. Ensure the sensor is correctly located and the sense wire is properly attached to both the sensor and the control. * Broken sensor or sense wire. Check for a broken sensor and test continuity across the sense wire, replacing components if damaged. * Sensor or sensor wire grounded to the unit. Check for resistance between the sensor rod/wire and the unit ground, correcting any shorts. * The control doesn't sense flame. Inspect the microamp signal from the burner flame. I...
  • S
    scaseyNov 26, 2025
    What to do if Lennox G60UH Furnace fails to fire but ignitor is energized?
    • K
      Katrina TerryNov 26, 2025
      If your Lennox furnace isn't firing in heating mode, even though the combustion air blower and ignitor are working, here's what to check: * Make sure gas is being supplied to the unit. Check the line pressure at the gas valve, ensuring it doesn't exceed 13" WC for natural and propane. The minimum line pressure should be 4.5" WC for natural gas and 8.0" WC for propane. * Inspect the gas valve wiring and connections at multi-pin control amp plugs or the valve for correctness and looseness. Correct wiring and/or replace any loose connections. * Determine if the gas valve or ignition control is defective. Verify that 24V is supplied to the gas valve approximately 35 seconds after heat demand starts. If voltage is present but the valve doesn't open, replace the valve. If 24V isn't suppli...
  • A
    Ashley StricklandDec 1, 2025
    Why Lennox Furnace burners shut down quickly?
    • W
      William ArnoldDec 1, 2025
      If the burners in your Lennox furnace light with a heating demand but the unit shuts down prematurely, consider these potential causes: * The unit is firing above 100% of the nameplate input. Verify that the manifold pressure matches the value listed on the nameplate. Check that the installed orifice size matches the size listed on the nameplate or installation instructions. Verify the input rate matches the value listed on the nameplate. * Gas orifices leak at the manifold connection. Tighten the orifice until the leak is sealed, being careful not to strip the threads. Check for gas leakage at the threaded orifice connection using an approved method for leak detection. * Insufficient flow through the heat exchanger caused by a sooted or restricted heat exchanger. Check for sooting ...

Summary

UNIT INFORMATION

G60 UH(X) SERIES UNITS

General overview of the G60UH(X) furnace series.

IMPORTANT SAFETY INFORMATION

Critical warnings regarding installation, service, and potential hazards.

SPECIFICATIONS

Gas Heating Performance

Key performance data including input, output, and AFUE ratings.

Connections and Blower Specifications

Physical connection sizes and blower motor details.

BLOWER DATA

G60 UH-24 A-045 and G60 UH-24 A-070 PERFORMANCE

Air volume and watt data for specific G60UH models.

BLOWER DATA Cont.

G60 UH-36 A-070 and G60 UH-36 B-090 PERFORMANCE

Air volume and watt data for specific G60UH models.

HIGH ALTITUDE; MANIFOLD PRESSURE INFORMATION

PARTS ARRANGEMENT

I-UNIT COMPONENTS

Key Components and Electronic Ignition

Description of transformer, switches, control board, and ignition process.

Integrated Control Board Features

Dip Switches, Jumpers, and Diagnostic LEDs

Configuration options and troubleshooting indicators on the control board.

DIAGNOSTIC CODES

Error Code Storage and Clearing

Procedures for accessing, reviewing, and clearing stored error codes.

Key Component Descriptions

Blower Motors, Ignitor, and Flame Sensor

Details on blower motors, ignitor function, and flame sensor.

Combustion Air Inducer and Rollout Switches

Limit Controls, Gas Valve, and Prove Switch

III-START-UP PROCEDURES

Preliminary Checks and Heating Start-Up

Essential inspections and the process for initiating heating operation.

IV-HEATING SYSTEM SERVICE CHECKS

Gas Piping and Pressure Checks

Guidelines for gas line installation, leak testing, and pressure verification.

Combustion and Gas Flow Verification

Manifold Adjustment and Gas Flow

Steps for adjusting manifold pressure and checking gas flow.

Typical Operating Characteristics

Blower, Temperature Rise, and Static Pressure Checks

How to adjust blower, measure temp rise, and check static pressure.

VI-MAINTENANCE PROCEDURES

Blower, Filters, Electrical, and Heat Exchanger Maintenance

Maintenance tasks for blower, filters, electrical, and heat exchanger components.

VII- Wiring and Sequence of Operation

Sequence of Operation (G60 UH-1 through -5)

Control Self Check and Thermostat Modes

Initial self-checks and unit response to thermostat settings.

HEATING SEQUENCE OF OPERATION FLOW CHART

COOLING SEQUENCE OF OPERATION

Fan Operation Sequences

Fan operation in cooling and continuous modes.

SureLight Board 100869 Operation Sequence

Control Self Check and Thermostat Modes

Self-checks and unit response based on thermostat settings.

HEATING SEQUENCE OF OPERATION FLOW CHART (Board 100869)

COOLING SEQUENCE OF OPERATION

Fan Operation Sequences

Fan operation in cooling and continuous modes.

CONTINUOUS LOW SPEED FAN SEQUENCE OF OPERATION

VIII- Field Wiring Applications and Jumper Settings

SureLight Board 18 M49 Wiring and Thermostat Configurations

Wiring examples for the 18M49 board and various thermostats.

B-SureLight Board 100869 Wiring

Thermostat Wiring Configurations

Examples of wiring for different thermostat types.

IX- Integrated Control Board Troubleshooting Guide

Troubleshooting Unit Operation Failures (Board 18 M34)

Diagnosing common operational failures like no power or reverse polarity.

Troubleshooting Combustion Air Inducer and Pressure Switch Issues

Troubleshooting Ignitor and Pressure Switch Issues

Troubleshooting Burner Ignition and Shutdown Issues

Troubleshooting Burner Shutdowns and Venting

Troubleshooting Flame Sense and Blower Failures

Troubleshooting Unit Operation Failures (Board 100869)

Troubleshooting Inducer and Pressure Switch Failures (Board 100869)

Troubleshooting Ignitor and Pressure Switch Failures (Board 100869)

Troubleshooting High Fire Operation Failures (Board 100869)

Troubleshooting Burner Ignition and Shutdown (Board 100869)

Troubleshooting Burner Shutdowns and Venting (Board 100869)

Troubleshooting Flame Sense and Blower Failures (Board 100869)

Lennox G60UH Specifications

General IconGeneral
TypeGas Furnace
Blower TypeVariable Speed
Ignition TypeDirect Spark Ignition
WarrantyLimited Lifetime Heat Exchanger Warranty, 5-year Limited Warranty on covered components
Fuel TypeNatural Gas
Blower MotorVariable Speed
StagesTwo-stage heating

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