Lennox Furnace SLP98V Manual

The Lennox SLP98V is a high-efficiency modulating gas furnace with variable-speed operation, achieving up to 98% AFUE efficiency. Features include SilentComfort™ technology, precise temperature control, durable stainless steel heat exchanger, compatibility with iComfort® Wi-Fi thermostat, quiet operation, and advanced diagnostics. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting Thermostat 7. Operation Modes 8. Maintenance 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Variable-speed blower motor, stainless steel heat exchanger, iComfort® compatible control board, gas valve, pressure switches, flame sensor, igniter.

Feature	Description
Variable-speed blower	Precise airflow control for consistent comfort
Stainless steel heat exchanger	Durable construction with 20-year warranty
SilentComfort™ technology	Ultra-quiet operation
iComfort® compatibility	Wi-Fi thermostat integration
Modulating gas valve	Precise heat output from 40% to 100% capacity
LED status lights	Diagnostic and operational indicators
Pressure switches	Safety monitoring of venting system
Flame sensor	Ensures proper ignition and flame detection
Igniter	Hot surface ignition system
Control board	Advanced microprocessor for system management

Installation

Professional installation required. Unpack and inspect contents. Ensure proper location and clearances.

Gas connection: Use approved gas piping; pressure test for leaks.
Electrical connection: 120V AC power supply; proper grounding required.
Venting: Use approved PVC piping for intake and exhaust.
Drain line: Connect condensate drain to proper disposal.
Thermostat wiring: Connect compatible thermostat per wiring diagram.

WARNING! Gas appliances can be hazardous; installation must comply with local codes. Use qualified HVAC technician.

First-Time Setup

Power on furnace; follow startup sequence.

System check: Control board performs self-diagnostic test.
Thermostat configuration: Set to HEAT mode; configure desired temperature.
Blower settings: Adjust airflow if needed for specific ductwork.
Gas pressure verification: Confirm proper gas pressure settings.
Combustion analysis: Verify proper venting and combustion efficiency.

CAUTION! Ensure proper ventilation and clearances maintained during setup.

Specifications

Efficiency: Up to 98% AFUE
Heating Capacity: 60,000 to 120,000 BTU/h (varies by model)
Stages: Fully modulating (40-100% capacity)
Blower Type: Variable-speed ECM motor
Heat Exchanger: Stainless steel
Voltage: 120V AC, 60Hz
Gas Type: Natural gas
Venting: PVC pipe (2" minimum)
Sound Level: As low as 65 dBA
Warranty: 20-year heat exchanger, 5-year parts

Controls and Settings

Access via thermostat or furnace control board. iComfort® thermostat provides full system control.

Thermostat Controls: Temperature setting, fan control, system mode, scheduling, Wi-Fi connectivity.

Furnace Controls: Power switch, control board with LED indicators, dip switch settings for configuration.

Operating Modes: HEAT, OFF, FAN ON. Advanced Settings: Blower speed adjustment, temperature differential, filter reminder, diagnostic codes.

Connecting Thermostat

Compatible with iComfort® Wi-Fi thermostat and standard 24V thermostats.

Turn off power to furnace before wiring.
Match thermostat wires to control board terminals (R, W, Y, G, C).
For iComfort®: Follow specific wiring diagram for advanced features.
Restore power; configure thermostat settings.

Tip: Use proper thermostat wire; ensure good connections at both ends.

Operation Modes

Modulating operation adjusts heat output for precise temperature control.

Startup: Control board checks safety devices before ignition.
Ignition: Hot surface igniter heats; gas valve opens; flame sensor confirms ignition.
Modulation: Gas valve adjusts flame height based on heating demand.
Blower operation: Variable-speed blower adjusts airflow for optimal comfort.
Shutdown: Gradual shutdown sequence for efficiency and comfort.

WARNING! Never bypass safety devices; regular professional maintenance required.

Maintenance

Regular maintenance ensures optimal performance and efficiency.

Monthly: Check and replace air filter if dirty.
Annual: Professional inspection and cleaning.
Seasonal: Verify proper operation before heating season.
As needed: Clean flame sensor and check venting.

CAUTION! Gas appliance maintenance should be performed by qualified technician.

Care & Cleaning

Turn off power before any cleaning. Keep area around furnace clean and unobstructed.

Air Filter: Replace every 1-3 months depending on usage and environment.

Exterior: Wipe with dry cloth; do not use water or cleaning chemicals.

Venting: Keep intake and exhaust clear of debris and obstructions.

CAUTION! Do not attempt to clean internal components; contact professional service.

Regulatory Information

UL certified; meets ANSI Z21.47 standards. CSA certified in Canada. Complies with Department of Energy efficiency standards. Copyright © Lennox Industries Inc. For support, visit www.lennox.com or contact 1-800-9-LENNOX. Installation must comply with local building codes and manufacturer specifications.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace not starting	Power, thermostat, safety lockout	Check power supply; verify thermostat settings; check for diagnostic codes.
No heat	Gas supply, igniter, flame sensor	Verify gas valve on; check for ignition failure; clean flame sensor.
Short cycling	Dirty filter, blocked vent, oversizing	Replace filter; check venting; verify proper sizing.
Blower not running	Motor, capacitor, control board	Check for power to blower; verify control signals; professional service.
Unusual noises	Loose components, airflow issues	Check for loose panels; verify proper airflow; professional inspection.

Diagnostic Codes: Refer to LED flash patterns on control board for specific error codes.

Service: 1-800-9-LENNOX; www.lennox.com