Gibson Furnace Service Manual

The Gibson Furnace is a high-efficiency residential heating system designed for reliable performance and energy savings. This manual covers installation, operation, maintenance, and troubleshooting for various Gibson furnace models. Below are key sections for safety procedures, technical specifications, installation guidelines, operational controls, maintenance schedules, and troubleshooting procedures.

1. Features at a Glance 2. Installation Guidelines 3. First-Time Setup 4. Technical Specifications 5. Controls and Settings 6. Electrical Connections 7. Maintenance Procedures 8. Safety Features 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: High-efficiency heat exchanger, Electronic ignition system, Multi-speed blower motor, Electronic thermostat interface, Safety shut-off switches, Air filter compartment.

Feature	Description
Heat Exchanger	Stainless steel construction for maximum efficiency and durability
Ignition System	Electronic hot surface ignition for reliable startup
Blower Motor	Multi-speed ECM motor for optimal airflow control
Thermostat Interface	Compatible with standard 24V thermostat systems
Safety Switches	Rollout switch, limit switch, pressure switch for safe operation
Filter Compartment	Easy-access slide-out filter rack for standard 1-inch filters
Gas Valve	Electronic modulating gas valve for precise temperature control
Control Board	Microprocessor-based control for system monitoring
Vent System	PVC venting for sidewall or roof termination
Drain System	Condensate drain for high-efficiency operation

Installation Guidelines

Unpack and inspect all components. Verify furnace model matches installation requirements.

Location Selection: Choose well-ventilated area with adequate clearance (minimum 24 inches front, 6 inches sides, 1 inch rear)
Gas Line Connection: Use approved gas piping materials; pressure test before connection
Electrical Wiring: Connect 120V AC power supply; install proper disconnect switch
Vent System: Install PVC vent pipes according to local codes and manufacturer specifications
Drain Connection: Route condensate drain to approved drainage location
Ductwork: Connect supply and return ducts; ensure proper sealing

WARNING! Gas furnaces produce carbon monoxide. Proper venting is critical for safety. All installations must comply with local building codes.

First-Time Setup

Complete installation verification before initial startup.

Gas Pressure Check: Verify inlet and manifold gas pressures match specifications
Electrical Check: Confirm proper voltage at control board; check ground connection
Vent System: Perform draft test to ensure proper vent operation
Thermostat Setup: Connect thermostat wires; configure heating cycle parameters
Initial Startup: Follow step-by-step startup sequence in service manual
System Check: Verify proper ignition, flame sensing, and blower operation

CAUTION! Only qualified HVAC technicians should perform initial setup and startup procedures.

Technical Specifications

Input Capacity: 40,000 - 120,000 BTU/H (varies by model)
Efficiency Rating: 80% - 96% AFUE (depending on model series)
Gas Type: Natural Gas or LP (conversion kit required for LP)
Electrical: 120V AC, 60Hz, 15 Amp circuit
Blower Capacity: 800 - 2000 CFM (adjustable speeds)
Static Pressure: Maximum 0.8 inches water column
Vent Size: 2-inch or 3-inch PVC (model dependent)
Filter Size: Standard 16x25x1 inch or 20x25x1 inch
Operating Temp Range: -30°F to 120°F ambient
Warranty: 20-year heat exchanger, 5-year parts

Controls and Settings

Access control board via front panel removal. Diagnostic LEDs indicate system status.

Control Board: POWER LED (green), STATUS LED (red/flashing codes), HEAT LED (yellow), FAN LED (blue).

Temperature Settings: Adjust via thermostat (minimum 40°F, maximum 90°F). Blower Settings: Adjust blower delay and speed taps. Gas Pressure: Adjust manifold pressure screw (3.5" WC natural gas, 10" WC LP). Limit Settings: Factory set high limit switch (200°F). Diagnostic Codes: Refer to LED flash patterns for error identification.

Electrical Connections

120V AC power supply, 24V thermostat circuit, blower motor connections.

Disconnect power before servicing electrical components
Verify proper voltage at control board terminals
Connect thermostat wires to R, W, G, C terminals
Check blower motor capacitor and wiring
Test safety circuit continuity (limit switches, rollout switch)

Tip: Use voltage tester to confirm power is disconnected before working on electrical components.

Maintenance Procedures

Regular maintenance ensures optimal performance and longevity.

Monthly: Check and replace air filter as needed
Seasonal: Inspect burners for proper flame pattern
Annual: Clean heat exchanger surfaces
Annual: Check and clean blower wheel and housing
Annual: Verify gas pressure and combustion analysis
Annual: Inspect vent system for obstructions
Annual: Check condensate drain line and trap
Biannual: Lubricate blower motor (if required)

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

Safety Features

Flame Rollout Switch: Shuts off gas if flame rolls out of burner compartment. High Limit Switch: Turns off burner if temperature exceeds safe limits. Pressure Switch: Verifies proper vent draft before ignition. Ignition Control: Monitors flame presence during operation. Thermal Fuse: One-time use safety device for extreme overheating.

Care & Cleaning

Disconnect power before cleaning. Use soft brush and vacuum for heat exchanger. Clean burners with compressed air. Wipe control board with dry cloth only.

CAUTION! Do not use water or chemical cleaners on electrical components. Never bypass safety devices.

Regulatory Information

UL certified for safety standards. ANSI Z21.47 compliant for gas-fired central furnaces. Meets DOE energy efficiency requirements. All installations must comply with National Fuel Gas Code (NFPA 54) and local building codes. For technical support, contact Gibson HVAC at 1-800-123-4567 or visit www.gibsonhvac.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power loss/thermostat	Check circuit breaker; verify thermostat setting; replace batteries.
No heat	Gas supply/ignition	Verify gas valve on; check igniter; inspect flame sensor.
Blower won't run	Motor/capacitor	Check blower motor; test capacitor; verify control board signal.
Short cycling	Filter/limit switch	Replace dirty filter; check high limit switch; verify airflow.
Strange odors	Dust/burning	Clean burners; check for overheating components; inspect wiring.
Error codes flashing	System fault	Refer to diagnostic chart; reset system; check sensors.

Reset Procedure: Turn thermostat to off position, wait 30 seconds, turn back to heat mode.

Service: 1-800-123-4567; www.gibsonhvac.com