Goodman Furnace Model GMS81155CNA Manual

The Goodman GMS81155CNA is a high-efficiency gas furnace with 80,000 BTU input capacity, 80% AFUE rating, single-stage operation, natural gas fuel type, multi-speed blower motor, electronic ignition system, aluminized steel heat exchanger, and compatibility with standard thermostat controls. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Aluminized steel heat exchanger, multi-speed direct drive blower, electronic ignition system, gas valve, pressure switches, flame sensor, limit switches.

Installation Requirements

Professional installation required. Verify local codes and obtain permits.

1. Location: Install in dry, clean area with adequate combustion air and service clearance.
2. Venting: Use approved PVC pipe for intake and exhaust; maintain proper slope.
3. Gas Connection: Use black iron pipe; pressure test for leaks.
4. Electrical: Connect to dedicated 115V circuit with proper grounding.
5. Ductwork: Ensure proper sizing and sealing for efficient airflow.

WARNING! Gas furnaces produce carbon monoxide; proper venting is critical. Only qualified technicians should install.

First-Time Setup

After installation, perform initial startup procedure.

1. Verify all connections: Gas, electrical, venting, and thermostat.
2. Install clean air filter in filter rack.
3. Set thermostat to lowest setting.
4. Turn gas supply valve to ON position.
5. Turn on electrical power to furnace.
6. Set thermostat to heat mode and raise temperature above room temp.
7. Verify proper ignition sequence and flame establishment.
8. Check for proper airflow and temperature rise.

CAUTION! Never bypass safety controls. If furnace fails to start properly, turn off power and call qualified technician.

Specifications

• Model: GMS81155CNA
• Input Capacity: 80,000 BTU/H
• Output Capacity: 64,000 BTU/H
• AFUE Rating: 80%
• Fuel Type: Natural Gas
• Stages: Single-Stage Operation
• Blower Motor: Multi-Speed Direct Drive
• Ignition: Hot Surface Electronic
• Electrical: 115V/60Hz, 6.5 Amps
• Vent Size: 3-inch PVC
• Filter Size: 16x25x1 inches
• Dimensions: 21"W x 21"D x 45"H

Controls and Settings

Integrated furnace control board manages all operations. Access door switch interrupts power when door removed.

Control Board LED: Flashing light indicates status codes for troubleshooting.

Blower Speeds: Adjustable for heating and continuous fan operation. Gas Valve: Regulates gas flow to burners. Limit Switches: Automatic shutdown if overheating detected. Pressure Switches: Verify proper venting operation before ignition.

Connecting Thermostat

Compatible with most 24VAC thermostats. Standard 5-wire connection.

1. Turn off power to furnace at electrical disconnect.
2. Remove furnace access panel to expose control board.
3. Connect thermostat wires to terminal block: R (24V), W (Heat), G (Fan), Y (Cool), C (Common).
4. Route thermostat cable through provided knockout.
5. Restore power and verify thermostat operation.

Tip: Use color-coded wires for easy identification and proper connection.

Operating Instructions

Normal operation controlled by thermostat settings.

1. Set thermostat to HEAT mode for winter operation.
2. Adjust temperature setting to desired comfort level.
3. Furnace will automatically cycle on and off to maintain temperature.
4. For continuous airflow, set thermostat fan to ON position.
5. For seasonal shutdown, turn thermostat to OFF and close gas supply valve.

WARNING! Never operate furnace without access panels properly installed. Keep combustible materials away from furnace.

Maintenance Procedures

Regular maintenance ensures efficient and safe operation.

1. Monthly: Check and replace air filter if dirty.
2. Annually: Professional inspection and cleaning recommended.
3. Burner Inspection: Check for proper flame pattern and color.
4. Heat Exchanger: Inspect for cracks or corrosion.
5. Vent System: Verify clear of obstructions.
6. Blower Assembly: Clean blower wheel and housing.
7. Drain System: Clear condensate drain lines.

Care & Cleaning

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

CAUTION! Do not use water or liquid cleaners on electrical components. Keep flame sensor and igniter clean and dry.

Regulatory Information

ANSI Z21.47/CSA 2.3: Certified for natural gas operation. UL Listed: Electrical components meet safety standards. For technical support, contact Goodman Manufacturing at 1-877-466-8626 or visit www.goodmanmfg.com. Serial number located on rating plate inside furnace.

Troubleshooting

LED Codes: Refer to control board flashing light pattern for specific error codes.

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