Goodman Furnace Manual Wiring Diagram

The Goodman Furnace Manual Wiring Diagram provides comprehensive electrical schematics and connection guidelines for Goodman furnace models. This manual covers wiring configurations, terminal connections, control board layouts, safety circuit wiring, thermostat connections, and troubleshooting electrical issues. Below are key sections for electrical specifications, wiring diagrams, installation guidelines, and troubleshooting.

1. Electrical Specifications 2. Wiring Diagram Overview 3. Terminal Connections 4. Control Board Wiring 5. Thermostat Connections 6. Safety Circuit Wiring 7. Power Supply Connections 8. Grounding Requirements 9. Installation Guidelines 10. Safety Precautions 11. Troubleshooting Electrical Issues

Electrical Specifications

Key electrical components: Control board, transformer, blower motor, inducer motor, gas valve, pressure switches, limit switches, flame sensor.

ComponentVoltage RatingWire Gauge
Main Power Supply120V AC, 60Hz14 AWG minimum
Control Transformer120V to 24V18-22 AWG
Blower Motor120V AC14 AWG
Inducer Motor120V AC16 AWG
Gas Valve24V AC18-22 AWG
Thermostat24V AC18-22 AWG
Limit Switches24V AC18-22 AWG
Pressure Switches24V AC18-22 AWG
Flame SensorMicroamp DC18-22 AWG

Wiring Diagram Overview

Standard wiring color codes and terminal designations for Goodman furnace models.

  1. Red (R): 24V AC hot from transformer
  2. White (W): Heat call from thermostat
  3. Green (G): Fan control from thermostat
  4. Yellow (Y): Cooling call from thermostat
  5. Blue (C): Common 24V return
  6. Black: 120V AC hot
  7. White: 120V AC neutral
  8. Green/Bare: Ground

WARNING! Always disconnect power before working on electrical connections. Verify voltage with multimeter.

Terminal Connections

Control board terminal layout and connection points.

  1. R: 24V power input from transformer
  2. C: Common 24V return
  3. W/W1: Heat stage 1
  4. Y/Y1: Cooling stage 1
  5. G: Indoor blower control
  6. L: System fault indicator
  7. COM: Common for accessory connections
  8. +/-: DC motor control (if applicable)

CAUTION! Ensure all connections are tight and secure. Loose connections can cause overheating and fire hazard.

Control Board Wiring

Thermostat Connections

Standard 5-wire thermostat configuration and color coding.

Terminal Designations: R (24V power), W (heat), Y (cool), G (fan), C (common)

Heat-only systems: R, W, C. Heat/Cool systems: R, W, Y, G, C. Heat pump systems: Additional O/B for reversing valve.

Safety Circuit Wiring

Safety devices in series with gas valve circuit: high limit switch, rollout switch, pressure switch, flame sensor.

  1. Disconnect power before testing safety circuits
  2. Check continuity of each safety device
  3. Verify proper voltage at gas valve terminals during call for heat
  4. Test flame sensor microamp reading (typically 1-10 μA)

Tip: Use multimeter to verify 24V at gas valve when all safety circuits are satisfied.

Power Supply Connections

Main power wiring requirements and connections.

  1. Connect black wire (hot) to L1 terminal
  2. Connect white wire (neutral) to L2/N terminal
  3. Connect green or bare wire to ground terminal
  4. Verify proper voltage: 115-125V AC
  5. Install appropriate fuse or circuit breaker (15-20 amp)
  6. Ensure polarity is correct (hot to hot, neutral to neutral)

WARNING! Incorrect wiring can damage control board and create shock hazard. Always verify with voltage tester.

Grounding Requirements

Proper grounding is essential for safety and proper operation.

Installation Guidelines

Follow NEC and local electrical codes. Use proper wire gauges and conduit where required.

CAUTION! All electrical work must comply with local codes. Use licensed electrician if unsure.

Safety Precautions

Always disconnect power before servicing. Use lockout/tagout procedures. Test voltage before touching wires. Wear appropriate PPE.

Troubleshooting Electrical Issues

SymptomPossible CauseCorrective Action
No power to furnaceTripped breaker, blown fuseCheck circuit breaker; replace fuse; verify power at disconnect
Control board not lightingTransformer failure, loose wiringCheck 24V at transformer; verify control board connections
Blower not runningMotor capacitor, control boardTest capacitor; check voltage at motor; verify control signal
No heat callThermostat, limit switchCheck thermostat wiring; test limit switches for continuity
Furnace locks outFlame sensor, pressure switchClean flame sensor; verify pressure switch operation

Reset: Power cycle furnace to clear lockout codes.

Service: Contact qualified HVAC technician for complex electrical issues.

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