Ruud Silhouette II Plus 2 Gas Furnace Manual

The Ruud Silhouette II Plus 2 is a high-efficiency gas furnace featuring two-stage heating, variable-speed blower motor, electronic ignition, durable heat exchanger construction, quiet operation, and energy-efficient performance. With AFUE ratings up to 96%, this furnace provides reliable heating for residential applications. Below are key sections covering safety, features, installation, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation Requirements 3. First-Time Setup 4. Technical Specifications 5. Controls and Operation 6. Venting and Combustion Air 7. Maintenance Procedures 8. Safety Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Two-stage gas valve, variable-speed ECM blower motor, aluminized steel heat exchanger, electronic ignition system, integrated control board, pressure switches, flame sensor, and condensate drainage system.

Feature	Description
Two-stage heating	Provides efficient low-stage operation for mild weather and high-stage for cold conditions
Variable-speed blower	ECM motor for quiet operation and improved humidity control
Electronic ignition	Hot surface igniter for reliable lighting without standing pilot
Heat exchanger	Durable aluminized steel construction with lifetime warranty
Control board	Integrated microprocessor for system monitoring and diagnostics
Pressure switches	Verify proper venting before ignition
Flame sensor	Monitors burner operation for safety shutdown
Condensate system	Removes acidic condensation from high-efficiency operation
Filter access	Easy-access filter compartment for standard 1-inch filters
LED status lights	Diagnostic indicators for troubleshooting

Installation Requirements

Professional installation required. Verify local codes and obtain permits.

Location selection: Install in dry, clean area with adequate clearance for service access.
Gas connection: Use black iron pipe with proper thread sealant; pressure test for leaks.
Electrical connection: 120V AC power supply with proper grounding.
Venting: PVC pipe system for direct vent or conventional venting as specified.
Combustion air: Ensure adequate fresh air supply per local codes.
Ductwork: Properly sized and sealed duct system for optimal performance.

WARNING! Gas furnaces produce carbon monoxide; improper installation can be fatal. Only qualified technicians should install this equipment.

First-Time Setup

Initial startup must be performed by qualified technician.

Verify installation: Check all connections, clearances, and venting.
Gas pressure adjustment: Set manifold pressure per specifications on rating plate.
Electrical connections: Verify proper voltage and grounding.
System checkout: Test ignition sequence, flame sensing, and safety controls.
Airflow adjustment: Set blower speeds for heating mode.
Customer orientation: Explain thermostat operation and basic maintenance.

CAUTION! Never attempt to adjust gas pressure or electrical connections without proper training and equipment.

Technical Specifications

Input Capacity: 40,000 to 120,000 BTU/hr (model dependent)
AFUE Rating: Up to 96% efficiency
Stages: Two-stage heating operation
Blower Type: Variable-speed ECM motor
Ignition: Hot surface electronic ignition
Gas Type: Natural gas (LP conversion kit available)
Electrical: 120V AC, 60Hz, 15 amp circuit
Venting: PVC, CPVC, or ABS (2-3 inch diameter)
Sound Rating: Ultra-quiet operation
Warranty: Lifetime heat exchanger, 10 years parts

Controls and Operation

Integrated control board manages all furnace functions with LED status indicators.

Thermostat Requirements: Compatible with most standard thermostats; for full two-stage operation, use compatible two-stage thermostat.

Operating Modes: Heating mode (two-stage), fan-only operation, system shutdown. Control Board Functions: Monitors safety devices, controls ignition sequence, manages blower operation, provides diagnostic codes. LED Status Lights: Flash codes indicate normal operation or fault conditions (refer to troubleshooting chart).

Venting and Combustion Air

Proper venting is critical for safe operation and efficiency.

Direct vent: Use concentric or separate PVC pipes through sidewall or roof.
Conventional vent: Metal B-vent through roof (check local codes).
Combustion air: Provide adequate fresh air per installation instructions.
Vent termination: Keep clear of obstructions, windows, and air intakes.
Condensate drainage: Route condensate to approved drain or condensate pump.

Tip: Regularly inspect vent terminations for blockages from snow, leaves, or debris.

Maintenance Procedures

Regular maintenance ensures optimal performance and longevity.

Monthly: Check and replace air filter as needed.
Annual professional service: Includes combustion analysis, heat exchanger inspection, blower cleaning, and safety check.
Seasonal: Inspect vent system, condensate drain, and clear drain trap.
Component inspection: Check flame sensor, igniter, pressure switches, and blower motor.
Electrical: Verify proper voltage and connections.
Gas system: Check for leaks and verify manifold pressure.

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

Safety Features

Multiple safety systems protect against hazardous conditions.

Safety Feature	Function
Flame rollout switches	Detect improper burner combustion
High limit switch	Prevents overheating
Pressure switches	Verify proper venting operation
Flame sensor	Confirms burner ignition
Ignition control	Limits ignition attempts
Condensate overflow	Shuts down if drain is blocked

Care & Cleaning

Regular cleaning maintains efficiency and prevents issues.

External cleaning: Wipe cabinet with damp cloth; avoid harsh chemicals. Filter replacement: Change 1-inch filters monthly during heating season. Vent inspection: Check termination for obstructions. Condensate drain: Flush with clean water annually. Professional cleaning: Annual cleaning of heat exchanger and blower assembly.

CAUTION! Never operate furnace without filter. Keep area around furnace clear of combustible materials.

Regulatory Information

UL listed and ANSI certified for safety and performance. Complies with U.S. Department of Energy efficiency standards. Manufactured to meet or exceed industry standards for residential gas furnaces. For technical support or warranty service, contact Ruud at 1-800-722-2102 or visit www.ruud.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, door switch	Check circuit breaker, thermostat settings, ensure door properly closed.
No heat	Gas supply, ignition	Verify gas valve on, check for ignition attempts, consult professional.
Blower won't stop	Thermostat, control board	Check thermostat fan setting, may indicate control board issue.
Frequent cycling	Filter, airflow	Replace dirty filter, check for blocked vents or registers.
Error codes flashing	Various faults	Count LED flashes and refer to diagnostic chart in service manual.
Unusual noises	Components, airflow	May indicate blower, inducer, or heat exchanger issues; call for service.

Reset Procedure: Turn thermostat to off, turn off power at furnace for 30 seconds, restore power, set thermostat to heat.

Service: 1-800-722-2102; www.ruud.com