Goodman Furnace GMP100-3 Manual

The Goodman GMP100-3 is a high-efficiency gas furnace with 80% AFUE rating, single-stage operation, multi-speed blower motor, hot surface ignition, and durable heat exchanger. Suitable for residential installation with natural gas or propane (with conversion kit). Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation Requirements 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Venting and Combustion Air 7. Operation Instructions 8. Maintenance Procedures 9. Care & Cleaning 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: Durable aluminized steel heat exchanger, hot surface ignition system, multi-speed direct drive blower, flame roll-out switches, pressure switches, and integrated control board.

Feature	Description
Heat Exchanger	Aluminized steel tubular design for durability
Ignition System	Hot surface ignition for reliable starts
Blower Motor	Multi-speed direct drive for airflow control
Gas Valve	Single-stage operation with manual shutoff
Control Board	Integrated furnace controller with LED status lights
Limit Switches	High temperature protection
Pressure Switches	Verifies proper venting operation
Flame Sensor	Monitors burner flame presence
Drain System	Condensate removal for efficient operation
Filter Rack	Standard 1-inch filter accommodation

Installation Requirements

Professional installation required. Verify local codes and obtain permits.

Location: Install in conditioned space with adequate clearance (see specifications).
Venting: Use approved PVC or metal venting materials per local codes.
Gas Supply: Connect to properly sized gas line with sediment trap.
Electrical: Connect to 120V AC power with proper grounding.
Ductwork: Ensure proper sizing and sealing of supply/return ducts.

WARNING! Gas furnaces produce carbon monoxide; proper venting is critical. Installation must comply with NFPA 54 and local codes.

First-Time Setup

After installation, perform initial startup procedure.

Verify installation: Check all connections, clearances, and venting.
Gas pressure: Adjust manifold pressure to specifications (3.5" WC natural gas).
Blower speed: Set appropriate speed for heating application.
Test operation: Start furnace and verify proper ignition sequence.
Check temperature rise: Ensure within specified range (35-65°F).

CAUTION! Only qualified technicians should perform startup and adjustment procedures.

Specifications

Model: GMP100-3
Input BTU/H: 100,000 BTU
Output BTU/H: 80,000 BTU
AFUE Rating: 80%
Gas Type: Natural gas (LP conversion available)
Electrical: 115V/60Hz/1Ph
Blower Motor: Multi-speed PSC
Static Pressure: 0.1" to 0.8" WC maximum
Temperature Rise: 35-65°F
Venting: Category I
Dimensions: Refer to installation manual

Controls and Settings

Integrated control board with LED status indicator. Thermostat connections: R, W, G, C.

LED Codes: Steady light = normal operation; 1 flash = pressure switch; 2 flashes = ignition lockout; 3 flashes = limit circuit; 4 flashes = flame roll-out.

Gas Valve: Single-stage operation with manual shutoff. Blower Speeds: Adjustable for heating application. Limit Switches: Automatic high temperature protection. Pressure Switches: Verify inducer operation and venting.

Venting and Combustion Air

Category I venting required. Use approved materials per local codes.

Vent sizing: Follow manufacturer specifications for pipe diameter and length.
Combustion air: Provide adequate fresh air supply per installation requirements.
Clearances: Maintain specified clearances to combustible materials.
Termination: Properly locate vent and intake terminals outdoors.

Tip: Regularly inspect vent system for obstructions or damage.

Operation Instructions

Normal operation controlled by thermostat.

Set thermostat to desired temperature above room temperature.
Furnace initiates call for heat: inducer motor starts, pressure switch closes.
Hot surface igniter heats up, gas valve opens.
Burners ignite, flame sensor confirms presence.
Blower motor starts after heat exchanger warm-up period.
When thermostat satisfied, gas valve closes, blower continues for post-purge.

WARNING! Never operate furnace without proper venting and combustion air. Install carbon monoxide detectors in living spaces.

Maintenance Procedures

Annual professional maintenance recommended.

Monthly: Check and replace air filter as needed
Annual: Clean burners and heat exchanger
Annual: Inspect and clean flame sensor
Annual: Check gas pressure and combustion
Annual: Lubricate blower motor if required
Annual: Inspect vent system and drain lines

Care & Cleaning

Keep furnace area clean and free of combustible materials.

CAUTION! Turn off power and gas supply before cleaning. Use compressed air for heat exchanger cleaning. Never use water or chemical cleaners on electrical components.

Regulatory Information

UL listed and ANSI certified. Complies with U.S. Department of Energy efficiency standards. Manufactured to meet or exceed industry standards for safety and performance. For technical support, contact Goodman Manufacturing at 1-877-466-8626 or visit www.goodmanmfg.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Furnace won't start	Power, thermostat, switch	Check power supply; verify thermostat setting; check door switch.
No heat	Gas supply, ignition	Verify gas valve on; check for ignition lockout; inspect flame sensor.
Short cycling	Filter, limit switch	Replace dirty filter; check for restricted airflow; verify limit operation.
Blower won't stop	Thermostat, control	Check thermostat fan setting; inspect control board.
Unusual noises	Motor, blower wheel	Inspect blower assembly; check for loose components; lubricate if needed.

Reset: Turn power off for 30 seconds to reset control board.

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