American Standard Furnace Maintenance Manual

The American Standard Furnace is a high-efficiency heating system designed for residential and light commercial applications. This maintenance manual covers gas and electric furnace models with features including variable-speed blower motors, electronic ignition systems, heat exchangers, air filters, thermostat compatibility, safety controls, and energy-efficient operation. Below are key sections for safety procedures, maintenance schedules, troubleshooting, parts identification, and service guidelines.

Features at a Glance

Key components: Heat exchanger, blower assembly, gas valve, electronic ignition system, air filter, pressure switches, limit controls, venting system.

Safety Precautions

Always follow safety procedures before performing maintenance.

1. Turn off electrical power: Switch off circuit breaker or disconnect switch.
2. Turn off gas supply: Close main gas valve to furnace.
3. Wait for cooling: Allow furnace to cool completely before servicing.
4. Use proper tools: Insulated tools and safety equipment required.

WARNING! Gas furnaces contain hazardous voltages and combustible gas. Only qualified technicians should perform internal repairs. Carbon monoxide poisoning risk exists with improper venting.

Maintenance Schedule

Regular maintenance ensures optimal performance and efficiency.

1. Monthly: Check and replace air filter if dirty.
2. Seasonal: Inspect vent system for obstructions before heating season.
3. Annual: Professional inspection and cleaning of heat exchanger, burners, and flue.
4. Biannual: Lubricate blower motor bearings if required (non-sealed units).

CAUTION! Document all maintenance activities. Keep service records for warranty validation.

Technical Specifications

• Input Capacity: 40,000 to 120,000 BTU/h depending on model
• Efficiency Rating: 80% to 98% AFUE
• Electrical Requirements: 115V/60Hz, 15 amp circuit
• Gas Type: Natural gas or propane (field convertible)
• Gas Pressure: Natural gas: 3.5" WC, Propane: 10" WC
• Airflow Capacity: 800 to 2000 CFM
• Static Pressure: 0.1 to 0.8 inches WC maximum
• Vent Size: 2" to 4" PVC depending on model
• Operating Temp Range: -30°F to 120°F ambient

Component Identification

Access internal components by removing front service panel. Control Board: Central control with status LEDs. Gas Valve: Regulates gas flow to burners. Heat Exchanger: Transfers heat to air stream. Blower Assembly: Moves air through system.

External Components: Filter access door, vent connections, gas line connection, electrical disconnect, drain connections, thermostat terminals.

Safety Devices: Rollout switches, limit switches, pressure switches, flame sensor. Diagnostic: LED status lights indicate system operation and fault codes.

Filter Maintenance

Proper filter maintenance ensures airflow and system efficiency.

1. Locate filter: Typically in return air duct or blower compartment.
2. Remove old filter: Note airflow direction arrow on filter frame.
3. Clean area: Vacuum filter slot before installing new filter.
4. Install new filter: Ensure proper orientation of airflow arrow.

Tip: Check filter monthly during heating season. Use manufacturer-recommended filter types only.

Electrical System Maintenance

Electrical components require careful inspection and testing.

1. Power off: Disconnect electrical power at service disconnect.
2. Inspect wiring: Check for loose connections, damaged insulation.
3. Test components: Use multimeter to verify voltages and continuity.
4. Check capacitors: Test run and start capacitors for proper capacitance.
5. Verify grounding: Ensure proper equipment grounding.
6. Inspect control board: Look for burned components or corrosion.

WARNING! High voltage present even when furnace is off. Only qualified personnel should perform electrical testing.

Gas System Maintenance

Gas system maintenance requires specialized tools and training.

1. Gas valve inspection: Check for leaks using bubble solution.
2. Burner cleaning: Remove and clean burners with soft brush.
3. Heat exchanger inspection: Visual check for cracks or corrosion.
4. Flame sensor cleaning: Gently clean with fine sandpaper or steel wool.
5. Pilot assembly: Clean pilot orifice and adjust flame if applicable.
6. Gas pressure: Verify inlet and manifold pressures are within specifications.

CAUTION! Gas leaks are extremely dangerous. Evacuate area and contact professional if gas odor detected.

Blower Motor Maintenance

Blower maintenance ensures proper airflow and system performance.

1. Access blower: Remove blower compartment door.
2. Inspect blower wheel: Check for dirt buildup and clean if necessary.
3. Check motor bearings: Listen for unusual noises indicating wear.
4. Lubricate if required: Some models require periodic oiling.
5. Check belt tension: On belt-drive models, adjust to proper tension.
6. Test operation: Verify proper RPM and airflow after maintenance.

Note: Most modern furnaces use direct-drive ECM motors that require no lubrication.

Troubleshooting Guide

Reset Procedure: Power off for 30 seconds, then restore power. Check diagnostic lights for error codes.

Service Procedures

Professional service procedures for certified technicians only.

1. Diagnostic mode: Access by specific button sequences on control board.
2. Error code interpretation: Refer to service manual for specific fault codes.
3. Component testing: Follow manufacturer testing procedures for sensors and switches.
4. Combustion analysis: Measure flue gases for proper combustion efficiency.
5. System calibration: Adjust gas pressure and airflow for optimal performance.
6. Final testing: Verify proper operation through complete heating cycle.

Service Contact: 1-800-american or www.americanstandard.com