Goodman GD9T800804BX 80% AFUE Two-Stage Natural Gas Furnace User Manual

1. Introduction

This manual provides essential information for the safe and efficient operation, installation, and maintenance of your Goodman GD9T800804BX 80% AFUE Two-Stage Downflow/Horizontal Multi-Speed 80k BTU Low NOx Natural Gas Furnace. Please read this manual thoroughly before attempting any installation, operation, or maintenance procedures.

The Goodman GD9T800804BX furnace is designed for residential heating applications, offering two-stage heating for enhanced comfort and efficiency. Its downflow/horizontal design provides flexible installation options.

Figure 1: Goodman GD9T800804BX Natural Gas Furnace. This image displays the exterior of the Goodman GD9T800804BX furnace, a gray, rectangular unit with a red Goodman logo and ventilation grilles on the front panel.

2. Safety Information

WARNING: Improper installation, adjustment, alteration, service, or maintenance can cause property damage, personal injury, or loss of life. Consult a qualified installer, service agency, or the gas supplier for information or assistance.

• Always turn off the electrical power and gas supply to the furnace before performing any service or maintenance.
• Ensure proper ventilation to prevent carbon monoxide poisoning. Do not block air vents.
• Keep flammable materials away from the furnace.
• Only qualified personnel should install, repair, or service this appliance.
• Do not store gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.

3. Installation (Setup)

Installation of this furnace must be performed by a qualified HVAC technician in accordance with all local and national building codes and safety regulations. This section provides general guidelines; refer to the detailed installation instructions provided with the unit for specific steps.

3.1 Pre-Installation Checks

• Verify that the furnace model matches the installation requirements (e.g., natural gas, BTU output, AFUE rating).
• Inspect the furnace for any shipping damage. Report any damage immediately.
• Ensure adequate clearance around the furnace for service and proper airflow.

3.2 Location and Mounting

The GD9T800804BX is designed for downflow or horizontal installation. Select a location that allows for proper combustion air, venting, and access for maintenance. Ensure the mounting surface is level and capable of supporting the furnace's weight.

3.3 Gas and Electrical Connections

All gas and electrical connections must comply with local codes. A dedicated electrical circuit is required. Ensure proper sizing of gas lines and electrical wiring.

3.4 Venting

Proper venting is critical for safety and efficiency. Install the venting system according to manufacturer instructions and local codes to ensure safe expulsion of combustion byproducts.

4. Operation

Once installed and commissioned by a qualified technician, operating your Goodman furnace is typically managed via a thermostat.

4.1 Thermostat Settings

1. Set the system switch on your thermostat to HEAT.
2. Set the fan switch to AUTO for normal operation, or ON for continuous fan operation.
3. Adjust the temperature setting to your desired comfort level. The furnace will cycle on and off to maintain this temperature.

4.2 Two-Stage Heating

This furnace features two-stage heating. In mild weather, the furnace operates at a lower capacity (first stage) for longer periods, providing more consistent temperatures and quieter operation. During colder periods, or if the thermostat calls for more heat, the furnace will switch to its higher capacity (second stage) to quickly reach the desired temperature.

5. Maintenance

Regular maintenance ensures the longevity and efficient operation of your furnace. Always disconnect electrical power and gas supply before performing maintenance.

5.1 Air Filter Replacement

Check the air filter monthly and replace it every 1-3 months, or more frequently if you have pets or allergies. A dirty filter restricts airflow, reducing efficiency and potentially damaging the furnace.

1. Locate the filter access panel.
2. Remove the old filter, noting the airflow direction.
3. Insert a new filter of the correct size, ensuring the airflow arrow points towards the furnace.

5.2 Annual Professional Inspection

It is highly recommended to have a qualified HVAC technician perform an annual inspection and tune-up. This includes checking:

• Burners and heat exchanger for cracks or corrosion.
• Ignition system and flame sensor.
• Blower motor and fan.
• Gas pressure and electrical connections.
• Flue and venting system for obstructions or leaks.

6. Troubleshooting

Before calling for service, review these common issues. Always ensure power and gas supply are on and the thermostat is set correctly.

6.1 No Heat

• Check thermostat settings (HEAT mode, desired temperature).
• Ensure furnace power switch is ON.
• Check circuit breaker for the furnace.
• Verify gas supply valve is open.
• Inspect air filter for excessive dirt.

6.2 Weak Airflow

• Replace dirty air filter.
• Ensure supply and return air vents are unobstructed.

6.3 Unusual Noises

Squealing or grinding noises may indicate a problem with the blower motor. Consult a qualified technician.

6.4 Error Codes

Modern furnaces often display error codes on a control board. Refer to the specific diagnostic codes in the full installation and operating manual or contact a service technician for interpretation and resolution.

7. Specifications

8. Warranty and Support

Goodman furnaces typically come with a limited warranty covering parts. Specific warranty terms and conditions are provided with the product documentation. Please register your product upon installation to activate the warranty.

For technical support, warranty claims, or to locate a qualified service technician, please contact Goodman customer service or visit the official Goodman website. Always provide your model and serial number when seeking support.

For more information, you may visit the Goodman Store on Amazon.