The Lennox Whisper Furnace is a high-efficiency gas furnace designed for quiet operation and optimal heating performance. Featuring advanced noise reduction technology, variable-speed blower motor, and energy-efficient operation, this furnace provides reliable comfort for residential applications. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.
Key components: Variable-speed ECM motor, insulated cabinet, direct spark ignition, sealed combustion chamber, multi-speed blower, integrated control board.
| Feature | Description |
|---|---|
| Variable-speed motor | Provides quiet operation and precise airflow control |
| Insulated cabinet | Reduces operating noise and improves efficiency |
| Direct spark ignition | Reliable ignition system with no standing pilot |
| Sealed combustion | Draws outside air for combustion, improves safety |
| Multi-speed blower | Adjustable airflow for optimal comfort |
| Integrated control | Microprocessor-based control for precise operation |
| Pressure switches | Safety verification of proper venting |
| Flame sensor | Monitors burner operation for safety |
| Limit switches | Prevents overheating conditions |
| Filter monitoring | Alerts when filter replacement is needed |
Professional installation recommended. Ensure proper clearances and venting.
WARNING! Gas appliances can be hazardous; installation must comply with local codes and manufacturer specifications. Only qualified technicians should perform installation.
Initial startup must be performed by qualified technician.
CAUTION! Never operate furnace without proper venting and combustion air. Ensure filter is installed before operation.
Integrated furnace control board with LED status indicators. Thermostat controls heating operation.
Control Board LED: Flashing patterns indicate system status and error codes.
Blower Speeds: Adjustable for heating and continuous fan operation. Temperature Rise: Verify within range on rating plate. Filter Reset: Control board monitors filter status and alerts when replacement needed. Diagnostic Codes: LED flash patterns for troubleshooting (refer to service manual).
Uses PVC pipe for intake and exhaust. Follow local codes for installation.
Tip: Always verify proper vent operation with manometer during startup.
Furnace operates automatically when thermostat calls for heat.
WARNING! Never adjust gas pressure or limit settings without proper training and equipment.
Regular maintenance ensures optimal performance and safety.
| Frequency | Maintenance Task |
|---|---|
| Monthly | Check and replace air filter if dirty |
| Annually | Professional inspection and cleaning |
| Annually | Check heat exchanger for cracks |
| Annually | Clean burners and combustion chamber |
| Annually | Verify gas pressure and combustion |
| Annually | Check vent system for obstructions |
| Annually | Inspect blower motor and wheel |
| Annually | Verify safety controls operation |
Multiple safety systems protect against hazardous conditions.
CAUTION! If furnace locks out on safety device, do not reset repeatedly. Contact qualified service technician.
ANSI Z21.47: Certified for natural gas and LP operation. UL listed. Complies with U.S. Department of Energy efficiency standards. CSA International certified. Manufactured to meet or exceed industry safety standards. For technical support, contact Lennox International Inc. or visit www.lennox.com. Copyright © 2025 Lennox Industries Inc. All rights reserved.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Furnace won't start | Power, thermostat, switch | Check circuit breaker, thermostat setting, door switch |
| No heat | Gas supply, ignition | Verify gas valve on, check for ignition attempts |
| Blower won't stop | Thermostat fan setting | Check thermostat fan setting (auto/on) |
| Furnace short cycling | Filter, airflow, limit | Replace filter, check for restricted airflow |
| Unusual noises | Motor, ductwork, vibration | Inspect blower wheel, check for loose components |
| Lockout condition | Safety device activation | Check control board LED code, reset if safe |
| Poor heating | Filter, gas pressure, sizing | Replace filter, verify proper gas pressure |
Reset Procedure: Turn power off for 30 seconds, then restore.
Service: Contact qualified HVAC technician for all repairs. 1-800-9-LENNOX; www.lennox.com