Lennox Pulse Furnace Installation Manual

The Lennox Pulse Furnace is a high-efficiency gas furnace featuring pulse combustion technology, electronic ignition, variable-speed blower motor, stainless steel heat exchanger, and advanced diagnostic controls. Designed for residential heating applications with AFUE ratings up to 97%, it requires professional installation and proper venting. Below are key sections for safety, specifications, installation procedures, wiring, startup, and troubleshooting.

Features at a Glance

Key components: Pulse combustion system, stainless steel heat exchanger, variable-speed blower, electronic controls, pressure switches, gas valve, and ignition system.

Safety Precautions

Critical safety information for installation and operation.

1. Gas line installation must comply with local codes and NFPA 54.
2. Electrical wiring must follow NEC and local electrical codes.
3. Venting must be properly sized and installed per manufacturer specifications.
4. Combustion air requirements must be met for safe operation.
5. Unit must be properly grounded and bonded.

WARNING! Gas furnaces can produce carbon monoxide. Proper installation and venting are critical to prevent CO poisoning. Install carbon monoxide detectors in living spaces.

Technical Specifications

• Model Series: Pulse G14, G16, G21 series
• Input Capacity: 40,000 to 140,000 BTU/hr
• AFUE Rating: Up to 97% efficiency
• Gas Type: Natural gas or LP/propane (conversion kit required)
• Gas Pressure: Natural gas: 3.5" WC; LP: 10" WC
• Electrical: 120V, 60Hz, 15A circuit
• Static Pressure: 0.1 to 0.9 inches WC
• Venting: PVC, CPVC, or ABS plastic pipe
• Dimensions: Varies by model (typically 21"W x 21"D x 40"H)
• Weight: 120 to 180 pounds

Pre-Installation Requirements

Site preparation and requirements before installation.

1. Verify local code compliance for gas, electrical, and mechanical installations.
2. Ensure adequate clearance: 0" sides, 1" front, 0" rear, 6" above, 24" service access.
3. Check existing ductwork for proper sizing and condition.
4. Verify gas supply line size and pressure requirements.
5. Ensure electrical service meets furnace requirements.
6. Plan venting route with proper slope and termination location.

CAUTION! Installation by qualified HVAC technician required. DIY installation may void warranty and create safety hazards.

Installation Procedures

Step-by-step installation process.

1. Position furnace: Place on level surface, ensure proper clearances.
2. Install filter system: Mount filter rack and install appropriate filter.
3. Connect ductwork: Secure supply and return ducts with proper sealing.
4. Install venting: Assemble PVC vent pipes with proper slope (1/4" per foot).
5. Connect gas line: Use black iron pipe with proper thread sealant.
6. Electrical connections: Connect line voltage and low-voltage thermostat wires.
7. Condensate drain: Install drain line with proper trap and routing.
8. Final inspection: Verify all connections and clearances.

Venting System

Pulse furnace requires special venting considerations.

1. Use only approved plastic pipe: PVC, CPVC, or ABS.
2. Maintain minimum 1/4" per foot slope toward furnace.
3. Maximum vent length: 40 feet with two 90° elbows (consult manual for specific models).
4. Vent termination: Must be 12" above ground, 3 feet from openings.
5. Combustion air intake: Separate pipe required, same size as exhaust.
6. Seal all joints with PVC cement approved for furnace applications.

Tip: Test vent system for leaks before final commissioning.

Electrical Wiring

Electrical connections and requirements.

1. Disconnect power before making electrical connections.
2. Line voltage: 120V, 15A dedicated circuit with proper grounding.
3. Low voltage: 24V thermostat connections (R, W, G, Y, C).
4. Blower motor: ECM motor with specific wiring configuration.
5. Grounding: Proper equipment grounding required per NEC.
6. Control board: Follow wiring diagram for proper connections.

WARNING! Electrical work must be performed by qualified electrician. Improper wiring can cause equipment damage or fire hazard.

Gas Supply Connection

Gas line installation and testing.

1. Use black iron pipe with proper thread sealant (pipe dope).
2. Install sediment trap before gas valve connection.
3. Use flexible connector if local codes permit.
4. Pressure test: Test gas line at 14" WC for 10 minutes (no drop).
5. Gas valve settings: Verify proper manifold pressure (3.5" WC natural gas).
6. Leak check: Use bubble solution on all connections.

Startup & Commissioning

Initial startup procedure and system verification.

1. Verify all connections are secure and proper clearances maintained.
2. Restore electrical power and gas supply.
3. Set thermostat to heat mode and raise temperature setting.
4. Observe ignition sequence: Purge, spark, gas valve opening, combustion.
5. Check gas pressure: Manifold and inlet pressures within specifications.
6. Measure temperature rise: 35-65°F across heat exchanger.
7. Verify blower operation: Proper airflow and static pressure.
8. Check vent operation: Proper draft and combustion.
9. Program thermostat for optimal operation.

Maintenance Guidelines

Routine maintenance requirements for optimal performance.

• Monthly: Check and replace air filter as needed.
• Annual: Professional inspection and cleaning.
• Clean flame sensor and inspect heat exchanger.
• Check condensate drain system and clear if necessary.
• Verify proper venting and combustion air.
• Lubricate blower motor if required (most are permanently lubricated).

CAUTION! Only qualified technicians should perform internal maintenance. Turn off power and gas before servicing.

Troubleshooting

Reset Procedure: Turn thermostat off, turn furnace power off for 30 seconds, restore power.

Service: Contact authorized Lennox dealer or 1-800-9-LENNOX for technical support.