Goodman GKS90703BX Gas Furnace Manual

The Goodman GKS90703BX is a high-efficiency gas furnace with 90,000 BTU input capacity, 90% AFUE rating, single-stage operation, multi-speed blower motor, aluminized steel heat exchanger, electronic ignition system, and compatibility with standard thermostat controls. Designed for residential heating applications with natural gas or propane conversion capability. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Aluminized steel tubular heat exchanger, induced draft combustion system, hot surface ignitor, multi-speed PSC blower motor, integrated control board, pressure switches, flame sensor, and filter rack.

Safety Information

Read all instructions before installation or service. Follow local codes and manufacturer guidelines.

1. Install furnace in compliance with NFPA 54/ANSI Z223.1 and NFPA 90B.
2. Provide adequate combustion air and proper venting.
3. Keep combustible materials away from furnace.
4. Install carbon monoxide detectors in living areas.
5. Disconnect electrical power before servicing.

WARNING! Gas furnaces produce carbon monoxide. Proper installation and maintenance are critical for safe operation. Never operate furnace without proper venting.

Installation Requirements

Furnace must be installed by qualified HVAC technician according to local codes.

1. Location: Install in upright position with adequate clearances (minimum 1" sides, 6" front, 24" top).
2. Combustion Air: Provide adequate fresh air per local codes and furnace requirements.
3. Venting: Use approved PVC pipe for Category IV venting; maintain proper slope.
4. Gas Supply: Install sediment trap; pressure test for leaks; verify manifold pressure.
5. Electrical: 120V AC power supply with proper grounding; install disconnect switch.
6. Ductwork: Size properly for required airflow; seal all connections.

CAUTION! Improper installation can cause fire, explosion, or carbon monoxide poisoning.

Specifications

• Model: GKS90703BX
• Input Capacity: 90,000 BTU/H
• Output Capacity: 81,000 BTU/H
• AFUE Rating: 90%
• Gas Type: Natural Gas (convertible to LP)
• Electrical: 120V/60Hz/1Ph
• Blower Motor: Multi-speed PSC
• Airflow: 1,200-1,600 CFM
• Static Pressure: 0.1-0.8 in. w.c.
• Venting: Category IV (PVC)
• Dimensions: 21"W x 21"D x 45"H
• Shipping Weight: 125 lbs

Controls and Operation

Integrated furnace control board manages all furnace operations with diagnostic capabilities.

Control Board: Monitors safety devices, controls ignition sequence, operates blower, provides diagnostic codes via LED.

Operation Sequence: Call for heat from thermostat → Inducer motor starts → Pressure switch proves draft → Hot surface ignitor energizes → Gas valve opens → Flame sensor proves ignition → Blower starts after heat exchanger warms → Normal heating cycle continues until thermostat satisfied.

Thermostat Settings: Connect standard 24V thermostat to R, W, G, C terminals for heating and fan control.

Venting and Combustion Air

Category IV vent system required. Use PVC pipe approved for furnace venting.

1. Vent Pipe: 2" or 3" PVC Schedule 40 pipe; maintain 1/4" per foot slope toward furnace.
2. Termination: Locate vent terminal at least 12" above ground/snow level; maintain clearances from windows, doors, and air inlets.
3. Combustion Air: Provide separate combustion air pipes or ensure adequate room air per installation requirements.
4. Concentric Kits: Approved concentric vent terminals available for sidewall installations.

Tip: Always verify proper draft and combustion with combustion analyzer during commissioning.

Electrical Connections

120V AC power supply required with proper grounding and disconnect switch.

1. Power Wiring: Connect L1 and L2 to furnace junction box; include proper overcurrent protection.
2. Thermostat Wiring: Standard 18-22 gauge low-voltage wire; connect R, W, G, C terminals.
3. Grounding: Proper equipment grounding required per NEC.
4. Disconnect: Install service disconnect within sight of furnace.

WARNING! Disconnect electrical power before servicing. Verify proper voltage and polarity.

Startup and Commissioning

Initial startup must be performed by qualified technician.

1. Verify all connections: Gas, electrical, venting, ductwork.
2. Check gas pressure: Natural gas manifold pressure 3.5" w.c.; adjust if necessary.
3. Test safety controls: Verify pressure switch, limit controls, flame sensor operation.
4. Measure combustion: Use combustion analyzer to verify CO levels and efficiency.
5. Check airflow: Verify static pressure and temperature rise within specifications.
6. Program thermostat: Set appropriate temperature differential and cycle rates.

CAUTION! Never bypass safety controls. Always complete combustion analysis.

Maintenance Procedures

Regular maintenance ensures safe and efficient operation.

• Monthly: Check and replace air filter as needed
• Annual: Professional inspection and cleaning
• Clean burners and heat exchanger
• Inspect flame sensor and ignitor
• Check vent system for obstructions
• Verify gas pressure and combustion
• Lubricate blower motor if required
• Check all electrical connections

WARNING! Only qualified technicians should perform internal furnace maintenance.

Regulatory Information

ANSI Z21.47/CSA 2.3: Certified for US and Canada. UL listed. Complies with Department of Energy efficiency standards. Manufactured by Goodman Manufacturing Company, L.P. For technical support, contact 1-877-466-8626 or visit www.goodmanmfg.com.

Troubleshooting

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

Service: 1-877-466-8626; www.goodmanmfg.com