Lennox Conservator III G16 Furnace Manual

The Lennox Conservator III G16 is a high-efficiency gas furnace with AFUE ratings up to 80%, two-stage gas valve operation, variable-speed blower motor, durable heat exchanger construction, electronic ignition system, built-in diagnostics, multiple-speed airflow settings, and compatibility with various thermostat systems. Designed for residential heating applications with natural gas or propane capability. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Two-stage gas valve, variable-speed blower motor, aluminized steel heat exchanger, hot surface igniter, flame sensor, pressure switches, control board with diagnostic LED.

Installation Requirements

Proper installation is critical for safe and efficient operation. Follow all local codes and manufacturer guidelines.

1. Location: Install in approved areas with adequate clearance and combustion air.
2. Venting: Use approved vent materials and maintain proper slope and termination.
3. Gas supply: Proper pipe sizing with sediment trap and shutoff valve.
4. Electrical: 120V AC power supply with proper grounding.
5. Ductwork: Properly sized and sealed duct system.

WARNING! Installation must be performed by qualified HVAC technician. Improper installation can cause fire, explosion, or carbon monoxide poisoning.

Initial Startup Procedure

Follow this sequence for proper furnace commissioning.

1. Verify all installation requirements are met and systems are properly connected.
2. Check gas pressure: Adjust manifold pressure to specifications (3.5" WC natural gas).
3. Set blower speeds: Adjust cooling and heating speeds per installation requirements.
4. Check temperature rise: Measure and verify within specified range (35-65°F).
5. Test safety controls: Verify proper operation of all limit switches and safety devices.
6. Program thermostat: Set up for two-stage operation if compatible thermostat installed.

CAUTION! Never bypass safety controls. Always verify proper operation before leaving installation.

Technical Specifications

• Input Capacity: 40,000 to 120,000 BTU/hr (multiple models)
• AFUE Rating: Up to 80%
• Gas Type: Natural gas or LP convertible
• Electrical: 120V AC, 60Hz
• Blower Motor: Variable-speed ECM
• Stages: Two-stage heating operation
• Venting: Category I, conventional venting
• Static Pressure: 0.1" to 0.8" WC maximum
• Temperature Rise: 35-65°F
• Dimensions: Varies by model (typically 21"W x 21"D x 45"H)

Controls and Settings

Integrated control board manages all furnace operations with diagnostic capabilities.

Control Board: Monitors system operation, provides diagnostic codes, controls staging sequence.

Thermostat Connections: R, C, W, W2, G, Y terminals for system control. Blower Speeds: Adjustable cooling and heating speeds via motor module. Gas Valve: Two-stage operation with pressure regulation. Limit Switches: High temperature protection. Pressure Switches: Verify inducer operation and venting. Diagnostic LED: Flash codes for troubleshooting (refer to chart on furnace door).

Venting and Combustion Air

Proper venting is critical for safe operation and efficiency.

1. Vent System: Use approved B-vent or listed venting materials.
2. Vent Sizing: Follow manufacturer specifications for proper diameter.
3. Combustion Air: Provide adequate fresh air supply per local codes.
4. Vent Termination: Maintain proper clearances from windows, doors, and air intakes.
5. Vent Slope: Maintain upward slope toward termination.

Tip: Always verify draft and perform combustion analysis during startup.

Maintenance Procedures

Regular maintenance ensures optimal performance and longevity.

1. Monthly: Check air filter; replace when dirty.
2. Annual: Professional inspection and cleaning recommended.
3. Burner Cleaning: Remove and clean burners annually.
4. Heat Exchanger: Inspect for cracks or corrosion.
5. Blower Assembly: Clean blower wheel and housing.
6. Vent System: Inspect for obstructions or deterioration.
7. Safety Controls: Test operation of all limit switches and safety devices.
8. Gas Connections: Check for leaks with bubble solution.

WARNING! Turn off electrical power and gas supply before performing maintenance. Only qualified technicians should service gas components.

Safety Features

Multiple safety systems protect against hazardous conditions. Flame Rollout Switches: Detect improper burner operation. High Limit Switches: Prevent overheating. Pressure Switches: Verify proper venting. Flame Sensor: Monitors burner flame. Ignition Control: Safe lighting sequence. Gas Valve: Positive shutoff when system off.

Care & Cleaning

Keep furnace area clean and clear of combustible materials.

CAUTION! Never store flammable materials near furnace. Keep intake and exhaust vents clear of obstructions. Use only manufacturer-approved replacement parts.

Regulatory Information

UL listed and ANSI certified for safety. Complies with applicable standards for gas-fired central furnaces. Manufactured to meet or exceed industry standards for performance and reliability. For technical support or warranty information, contact Lennox Industries Inc. or visit www.lennox.com. Installation must comply with National Fuel Gas Code NFPA 54/ANSI Z223.1 and local building codes.

Troubleshooting

Reset Procedure: Turn thermostat to off position, turn off electrical power for 30 seconds, restore power, set thermostat to heat mode.

Service: Contact qualified HVAC technician for all repairs. Lennox dealer locator: 1-800-9-LENNOX or www.lennox.com