Inter-city Products GNI Furnace Manual

The Inter-city Products GNI Furnace is a high-efficiency gas furnace designed for residential heating applications. This unit features advanced combustion technology, multiple heating stages, variable-speed blower motor, electronic ignition system, built-in safety controls, and compatibility with standard thermostat systems. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

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

Features at a Glance

Key components: Gas valve assembly, heat exchanger, blower motor, electronic control board, ignition system, pressure switches, flame sensor, and venting system.

Feature	Description
Gas valve	Precision gas flow control with multiple safety features
Heat exchanger	Stainless steel construction for durability and efficiency
Blower motor	Variable-speed ECM motor for quiet operation
Control board	Microprocessor-based for precise temperature control
Ignition system	Hot surface ignition for reliable startup
Pressure switches	Safety monitoring of combustion air flow
Flame sensor	Continuous flame detection for safety
Venting system	PVC pipe compatible for sidewall or roof venting
Filter access	Easy-access filter compartment for maintenance
Diagnostic lights	LED status indicators for troubleshooting

Installation

Unpack and inspect all components. Ensure proper clearances and ventilation.

Position furnace: Place on stable, level surface with proper clearances.
Connect gas supply: Use approved gas pipe and fittings; pressure test for leaks.
Install venting: Use PVC pipe per local codes; ensure proper slope and termination.
Electrical connections: Connect to 120V power supply; install disconnect switch.
Connect thermostat: Use 18-gauge wire for thermostat connections.
Install air filter: Insert proper size filter in filter compartment.

WARNING! Gas appliances require professional installation. Only qualified technicians should perform installation. Ensure proper ventilation and gas connections.

First-Time Setup

Complete installation verification before initial startup.

Gas pressure check: Verify inlet and manifold gas pressures are within specifications.
Venting verification: Confirm proper draft and venting operation.
Electrical check: Verify proper voltage and grounding.
Thermostat setup: Program thermostat for heating operation.
Initial startup: Follow lighting instructions; observe first heating cycle.
Performance check: Monitor temperature rise and system operation.

CAUTION! Never bypass safety controls. Test all safety devices before placing in service.

Specifications

Heating Capacity: 40,000 - 120,000 BTU/h (model dependent)
Efficiency: 80% - 96% AFUE (model dependent)
Gas Type: Natural gas or LP (conversion kit required)
Electrical: 120V AC, 60Hz, 15 amp circuit
Blower Motor: Variable-speed ECM
Stages: Single or two-stage operation
Venting: PVC, CPVC, or ABS (2" - 3" diameter)
Filter Size: 16x25x1 inch standard
Warranty: 10-year heat exchanger, 5-year parts
Operating Temp Range: -30°F to 120°F ambient

Controls and Settings

Access control board via front panel. Diagnostic lights indicate system status.

Control Board: POWER switch, FAN control, SYSTEM switch (HEAT/COOL/OFF), diagnostic LED indicators.

Gas Valve: Manual shutoff, pressure test ports. Blower Settings: Speed taps for heating and cooling modes. Limit Controls: High-limit switch, rollout switches. Thermostat Connections: R, W, Y, G, C terminals. Diagnostic Codes: Flash patterns indicate specific fault conditions.

Connecting Thermostat

Compatible with most 24V thermostat systems. Standard 5-wire connection.

Turn off power to furnace at disconnect switch.
Remove control board access panel.
Connect thermostat wires: R (24V), W (Heat), Y (Cool), G (Fan), C (Common).
Secure connections and replace access panel.
Restore power and test thermostat operation.

Tip: Use thermostat with compatible features for optimal performance.

Operating Procedures

Normal heating operation with automatic safety monitoring.

Set thermostat to desired temperature.
Furnace initiates call for heat sequence.
Inducer motor starts and pressure switches prove airflow.
Hot surface igniter heats up and gas valve opens.
Flame sensor confirms ignition and main burners operate.
Blower motor starts after heat exchanger warm-up delay.
System runs until thermostat satisfied, then shuts down in reverse sequence.

WARNING! Never operate furnace with access panels removed. Keep combustible materials away from furnace.

Maintenance Schedule

Regular maintenance ensures optimal performance and safety.

Maintenance Task	Frequency	Procedure
Air filter replacement	Monthly	Replace or clean filter as needed
Visual inspection	Seasonal	Check for debris, corrosion, damage
Burner cleaning	Annual	Clean burners and heat exchanger
Blower cleaning	Annual	Clean blower wheel and housing
Vent inspection	Annual	Check vent pipes for obstructions
Gas pressure check	Annual	Verify proper gas pressures
Safety device test	Annual	Test all limit and safety switches

Care & Cleaning

Turn off power and gas supply before cleaning. Use soft brush and vacuum for dust removal.

CAUTION! Never use water or liquid cleaners on electrical components. Keep flame sensor and igniter clean and dry.

Regulatory Information

ANSI Z21.47: Certified for safety standards. UL listed. Meets Department of Energy efficiency requirements. CSA International certified. For technical support, contact Inter-city Products at 1-800-422-4328 or visit www.intercityproducts.com. All installations must comply with local building codes and regulations.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, door switch	Check power supply; verify thermostat setting; ensure door switch engaged.
No heat	Gas supply, ignition, flame sensor	Verify gas valve on; check for ignition; clean flame sensor.
Short cycling	Filter, limit switch, airflow	Replace filter; check limit switch; verify proper airflow.
Blower won't run	Motor, capacitor, control board	Check motor operation; test capacitor; verify control board signals.
Lockout condition	Safety device tripped	Reset power; check diagnostic lights; address underlying safety issue.
Unusual noises	Blower, inducer, heat exchanger	Inspect blower wheel; check inducer motor; examine heat exchanger.

Reset Procedure: Turn power off for 30 seconds, then restore.

Service: 1-800-422-4328; www.intercityproducts.com