Goodman Furnace Installation Manual GMVC95

The Goodman GMVC95 is a high-efficiency gas furnace with variable-speed ECM blower motor, multi-speed operation, aluminized steel tubular heat exchanger, two-stage gas valve, hot surface ignition, induced draft combustion system, and diagnostic LED lights. Rated at 95% AFUE efficiency with input capacities from 40,000 to 120,000 BTU/h. Below are key sections for safety, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Safety Information 3. Installation Requirements 4. Specifications 5. Electrical Connections 6. Gas Line Connections 7. Venting System 8. Startup and Commissioning 9. Control Settings 10. Maintenance 11. Troubleshooting

Features at a Glance

Key components: Variable-speed ECM blower motor, two-stage gas valve, aluminized steel heat exchanger, hot surface ignition system, induced draft motor, pressure switches, diagnostic LED.

FeatureDescription
Variable-speed ECM blowerEnergy-efficient motor with multi-speed operation
Two-stage gas valveProvides high and low fire operation for comfort
Aluminized steel heat exchangerDurable corrosion-resistant construction
Hot surface ignitionReliable electronic ignition system
Induced draft combustionSealed combustion system for safety and efficiency
Diagnostic LEDFlashing code display for troubleshooting
Pressure switchesSafety devices to verify proper venting
Multi-speed blower settingsAdjustable cooling and heating speeds
95% AFUE efficiencyHigh-efficiency gas furnace operation
Dual-fuel capabilityCompatible with heat pump systems

Safety Information

Read all instructions before installation. Follow local codes and manufacturer guidelines.

  1. Installation must comply with National Fuel Gas Code and local codes.
  2. Furnace must be installed by qualified HVAC technician.
  3. Ensure proper combustion air and ventilation.
  4. Verify gas type matches furnace rating plate.
  5. Check for gas leaks before startup.

WARNING! Risk of fire, explosion, carbon monoxide poisoning, and electrical shock. Follow all safety precautions. Install carbon monoxide detectors.

Installation Requirements

Proper location, clearances, and mounting requirements.

  1. Location: Indoor installation only, protected from weather and moisture.
  2. Clearances: Minimum 1" from combustible materials, 24" service clearance front.
  3. Mounting: Level platform, vibration isolation if needed.
  4. Combustion air: Adequate fresh air supply per local codes.
  5. Drain line: Proper condensate drainage system required.

CAUTION! Furnace is heavy; use proper lifting equipment. Ensure adequate structural support.

Specifications

Electrical Connections

Follow NEC and local electrical codes. Disconnect power before servicing.

  1. Main power: 115V circuit with proper disconnect switch.
  2. Thermostat wiring: Low voltage connections (R, W, Y, G, C).
  3. Grounding: Proper equipment grounding required.
  4. Blower speeds: Adjust cooling/heating speeds per requirements.
  5. Safety switches: Connect door safety switch properly.

Tip: Use copper conductors only. Verify proper voltage at furnace.

Gas Line Connections

Gas piping must be sized properly and pressure tested.

  1. Pipe sizing: Size gas line per local codes and furnace input.
  2. Shutoff valve: Install manual gas shutoff valve near furnace.
  3. Drip leg: Install sediment trap in gas line.
  4. Pressure test: Test for leaks with soap solution.
  5. Gas pressure: Verify manifold pressure per rating plate.

WARNING! Use pipe joint compound rated for natural gas. Test thoroughly for leaks.

Venting System

PVC/CPVC vent pipe required for condensing furnace.

  1. Vent material: Schedule 40 PVC or CPVC pipe.
  2. Vent sizing: Follow manufacturer guidelines for pipe size.
  3. Termination: Proper outdoor termination with screens.
  4. Slope: Horizontal runs slope back to furnace 1/4" per foot.
  5. Clearances: Maintain proper clearance to combustible materials.

CAUTION! Do not use metal vent pipe. Ensure proper support and sealing.

Startup and Commissioning

Complete system checkout before initial operation.

  1. Gas pressure: Set manifold pressure to specifications.
  2. Combustion analysis: Verify CO and O2 levels.
  3. Blower operation: Check all speed settings.
  4. Temperature rise: Verify within rating plate range.
  5. Safety devices: Test all limit switches and pressure switches.

WARNING! Never bypass safety devices. Complete combustion analysis required.

Control Settings

DIP switch settings for blower speeds and operation modes.

Blower Speeds: Adjust cooling and heating speeds via DIP switches. Gas Valve: Two-stage operation with timing delays. Ignition Control: Automatic trial for ignition with safety lockout. Diagnostic LED: Flashing codes for troubleshooting.

Maintenance

Annual maintenance required for safe operation.

  1. Filter: Replace monthly during heating season.
  2. Heat exchanger: Annual visual inspection.
  3. Blower: Clean annually, check motor amperage.
  4. Vent system: Inspect for obstructions annually.
  5. Drain system: Clean condensate trap and line.

CAUTION! Disconnect power before servicing. Only qualified technicians should perform maintenance.

Troubleshooting

SymptomPossible CauseCorrective Action
Furnace won't startPower, thermostat, door switchCheck disconnect, thermostat settings, door switch engagement.
No heatGas supply, ignition, pressure switchVerify gas valve on, check for spark, test pressure switches.
Short cyclingDirty filter, high limitReplace filter, check airflow, verify limit operation.
Blower won't runMotor, capacitor, control boardCheck motor voltage, test capacitor, verify control signals.
Lockout modeIgnition failure, safety deviceReset power, check gas valve, verify flame sensor.

LED Codes: Refer to control board diagnostic chart for flashing codes.

Service: Contact qualified HVAC technician for all repairs.

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