Miller Gas Furnace Owners Manual

The Miller Gas Furnace is a high-efficiency residential heating system designed for reliable performance and energy savings. This furnace features advanced combustion technology, multiple safety systems, variable-speed blower motor, electronic ignition, and compatibility with various thermostat systems. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Heat exchanger, burner assembly, blower motor, gas valve, ignition system, pressure switches, flame sensor, control board.

Installation

Unpack and inspect all components. Ensure proper clearances and venting requirements.

1. Position furnace: Place on stable, level surface with proper clearances to combustible materials.
2. Connect gas supply: Use approved gas piping and fittings; pressure test for leaks.
3. Install venting: Use approved PVC or metal vent pipe as required by local codes.
4. Electrical connections: Connect 120V power supply and thermostat wiring.
5. Drain connections: Install condensate drain line for high-efficiency models.

WARNING! Installation must be performed by qualified HVAC technician. Gas leaks can cause explosion or fire.

First-Time Setup

Initial startup and system configuration by qualified technician.

1. Gas pressure adjustment: Set manifold pressure according to specifications.
2. Blower speed settings: Configure cooling and heating speeds for proper airflow.
3. Thermostat configuration: Program thermostat for proper system operation.
4. Safety checks: Verify all safety controls and limit switches function properly.
5. Combustion analysis: Check and adjust air-fuel mixture for optimal efficiency.

CAUTION! Do not attempt first-time startup without proper training and equipment.

Specifications

• Heating Capacity: 40,000 - 120,000 BTU/h depending on model
• Efficiency Rating: Up to 98% AFUE
• Gas Type: Natural gas or LP/propane (conversion kit required)
• Electrical: 120V AC, 60Hz, 15 amp circuit
• Blower Motor: Variable-speed ECM
• Sound Rating: Ultra-quiet operation
• Venting: PVC, ABS, or CPVC for high-efficiency models
• Warranty: Limited lifetime heat exchanger warranty
• Operating Temp Range: -30°F to 120°F ambient

Controls and Settings

Access control board via front panel. Status lights indicate system operation and fault codes.

Thermostat Controls: POWER, FAN (Auto/On), HEAT/COOL mode, temperature setting, program schedules.

System Settings: Blower speed adjustments, temperature rise verification, gas pressure settings, diagnostic mode access. Safety Controls: High limit switch, rollout switches, pressure switches, flame sensor, ignition control. Maintenance Settings: Filter reminder reset, service interval indicators, system status monitoring.

Connecting Thermostat

Compatible with most 24V thermostat systems including programmable and smart thermostats.

1. Turn off power to furnace at circuit breaker.
2. Remove old thermostat and label wires.
3. Connect wires to new thermostat: R (power), W (heat), G (fan), C (common), Y (cooling).
4. Mount thermostat and restore power.
5. Configure thermostat settings for furnace operation.

Tip: Use compatible thermostat for optimal system performance and efficiency.

Operating Procedures

Normal heating operation and seasonal startup procedures.

1. Seasonal startup: Set thermostat to HEAT mode and desired temperature.
2. System sequence: Thermostat calls for heat, inducer motor starts, pressure switch verifies, ignition sequence begins, gas valve opens, burner ignites, blower starts after heat exchanger warms.
3. Normal operation: System cycles on and off to maintain set temperature.
4. Fan operation: AUTO mode runs blower only during heating cycle; ON mode runs continuously.
5. Shutdown: System shuts down in reverse sequence when thermostat is satisfied.

WARNING! Never block air vents or returns. Keep combustible materials away from furnace.

Safety Features

Multiple safety systems protect against hazardous conditions. Flame rollout switches: Shut off gas if flame rolls out of burner compartment. High limit switch: Turns off burners if temperature exceeds safe limits. Pressure switches: Verify proper venting before allowing ignition. Flame sensor: Monitors burner flame and shuts off gas if flame is lost. Ignition control: Limits ignition attempts to prevent gas buildup.

Maintenance & Cleaning

Regular maintenance ensures optimal performance and safety.

1. Monthly: Check and replace air filter as needed.
2. Seasonal: Inspect burners, heat exchanger, and venting system.
3. Annual: Professional inspection and cleaning by qualified technician.
4. Clean flame sensor and inspect ignition system.
5. Check condensate drain system and clear if necessary.

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

Regulatory Information

UL certified for safety standards. ANSI Z21.47 compliant for gas-fired central furnaces. Meets DOE energy efficiency standards. CSA certified for Canadian installations. For technical support, visit www.millerfurnace.com or contact 1-800-645-3476. All installations must comply with local building codes and regulations.

Troubleshooting

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

Service: 1-800-645-3476; www.millerfurnace.com