Goodman Downflow Furnace Manual

The Goodman Downflow Furnace is a high-efficiency gas furnace designed for downflow installation configurations, featuring variable-speed blower motors, electronic ignition systems, multiple heating stages, and advanced safety controls. Suitable for residential applications with natural gas or propane compatibility. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Multi-speed direct drive blower, hot surface igniter, flame sensor, pressure switches, gas valve, limit controls, and control board.

Installation Requirements

Professional installation recommended. Verify local codes and obtain permits.

1. Location: Install in approved locations with proper clearances to combustibles.
2. Gas Connection: Use black iron pipe with proper thread sealant.
3. Electrical: 120V AC power supply with proper grounding.
4. Venting: Category I venting for natural draft; PVC for high-efficiency models.
5. Combustion Air: Ensure adequate fresh air supply.

WARNING! Gas appliances can be hazardous; installation by qualified technician required. Follow all safety codes.

First-Time Setup

Initial startup and commissioning procedures.

1. Gas Pressure Check: Verify manifold pressure per specifications.
2. Venting Verification: Confirm proper draft and venting operation.
3. Electrical Connections: Check voltage and thermostat wiring.
4. Airflow Adjustment: Set blower speeds for heating mode.
5. Safety Testing: Test limit controls and pressure switches.

CAUTION! Never bypass safety controls. Test carbon monoxide detectors after installation.

Technical Specifications

• Input Capacity: 40,000-120,000 BTU/h range
• Efficiency: 80% AFUE and higher models available
• Gas Type: Natural gas or propane (conversion kit required)
• Electrical: 120V AC, 60Hz, 15 amp circuit
• Blower Motor: Multi-speed PSC or ECM variable speed
• Venting: Category I (B-vent) or PVC for condensing models
• Dimensions: Varies by model (typical: 21"W x 21"D x 40"H)
• Operating Temp Range: -30°F to 150°F ambient
• Warranty: Limited lifetime heat exchanger warranty

Controls and Settings

Integrated furnace control board with diagnostic capabilities.

Thermostat Connections: R, W, G, Y, C terminals for system control.

Blower Speeds: Adjustable heating and cooling speeds via motor taps. Gas Valve: Pressure adjustment screws (professional service only). Limit Controls: Automatic high-temperature shutdown. Pressure Switches: Verify venting operation. Diagnostic Lights: LED flash codes for troubleshooting.

Gas Line Connections

Proper gas piping installation requirements.

1. Pipe Sizing: Size gas line according to length and BTU requirements.
2. Shut-off Valve: Install manual gas shut-off valve within 6 feet.
3. Drip Leg: Install sediment trap before gas connection.
4. Leak Testing: Test all connections with soap solution.
5. Pressure Test: Verify manifold pressure with manometer.

Tip: Use two wrenches when connecting gas lines to prevent damage.

Venting and Combustion Air

Venting system requirements for safe operation.

1. Vent Material: Use approved B-vent or PVC piping.
2. Vent Size: Match furnace outlet size (typically 3-5 inches).
3. Clearances: Maintain required clearances to combustibles.
4. Termination: Proper roof or wall termination per code.
5. Combustion Air: Provide adequate fresh air supply.
6. Draft Verification: Confirm proper draft during operation.

WARNING! Improper venting can cause carbon monoxide hazards. Never operate with blocked vents.

Maintenance Schedule

Regular maintenance requirements for optimal performance.

1. Monthly: Check and replace air filters as needed.
2. Annual: Professional inspection and cleaning.
3. Seasonal: Verify thermostat operation and safety controls.
4. Blower Maintenance: Clean blower wheel and housing annually.
5. Heat Exchanger: Visual inspection for cracks or damage.
6. Venting: Check for obstructions and proper draft.

CAUTION! Turn off power and gas supply before performing any maintenance.

Safety Features

Built-in safety systems for protection.

Regulatory Information

ANSI Z21.47/CSA 2.3: Certified to national gas appliance standards. UL Listed: Electrical components UL certified. For natural gas use with heating capacity below 225,000 BTU/h. Installation must comply with National Fuel Gas Code NFPA 54/ANSI Z223.1 and local codes. For support, contact Goodman Manufacturing at 1-877-466-8626 or visit www.goodmanmfg.com.

Troubleshooting

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

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