American Standard Furnace Not Igniting: Troubleshooting and Repair Steps

The article explains practical, step-by-step troubleshooting for an American Standard furnace that won’t ignite, highlighting common causes, safe diagnostics, and options for repair or replacement. It helps homeowners identify likely issues such as thermostat settings, power problems, ignition failures, gas supply issues, and safety sensor faults so informed decisions can be made.

Symptom	Likely Cause	Quick Action
No ignition light or flame	Faulty ignitor, gas valve, or pilot	Check power, listen for clicks, inspect ignitor
Clicking but no flame	Gas supply or valve issue	Verify gas on, smell test, call utility if needed
Flame lights then shuts off	Flame sensor dirty or faulty	Clean flame sensor, replace if needed
Short cycling	Thermostat, pressure switch, or vent blockage	Inspect vent, check error codes, reset

How An American Standard Furnace Ignition System Works

Understanding the ignition process helps pinpoint failures. Modern American Standard furnaces typically use either an intermittent pilot system with an electronic igniter or a hot surface ignitor (HSI). The thermostat signals the control board to start a heating cycle, the inducer motor runs to establish proper venting, the gas valve opens, and the ignitor lights the gas. A flame sensor confirms ignition; if not detected, the control board shuts off gas to prevent unsafe conditions.

Key Components: thermostat, control board, inducer motor, pressure switch, ignitor (hot surface or spark), gas valve, flame sensor, burners, and venting.

Initial Safety Checks Before Troubleshooting

Always prioritize safety. Turn off power to the furnace at the service switch or breaker before opening access panels, and shut off the gas at the appliance valve if a gas leak is suspected. If the smell of gas is present, leave the home immediately and call the gas utility or 911.

Use basic protective gear such as gloves and eye protection. If uncomfortable with electrical or gas systems, contact a qualified HVAC technician.

Step-By-Step Troubleshooting Guide

1. Verify Thermostat And User Settings

Confirm the thermostat is set to Heat and the setpoint is above room temperature. Replace thermostat batteries if applicable and check any schedule or hold settings that could prevent a call for heat.

For smart thermostats, verify Wi-Fi connectivity and that the thermostat is configured for a gas furnace. A faulty thermostat or wiring can prevent the furnace from receiving the ignition signal.

2. Check Power To The Furnace

Ensure the furnace’s service switch is ON and the circuit breaker hasn’t tripped. Many furnaces have an internal switch or door interlock; panels must be fully seated to allow operation. If the furnace control board shows no lights, the issue may be electrical.

If the breaker trips repeatedly, do not reset more than once; call a technician to avoid electrical hazards.

3. Listen And Observe During A Call For Heat

When the thermostat calls for heat, listen for the inducer motor to start (a steady whirring sound). After a few seconds, the ignitor should activate—HSI glows bright orange or a spark igniter will click. If these steps don’t occur, note which step fails.

Observation Notes: No inducer sound indicates a control board or power issue. Inducer runs but no ignitor action suggests ignitor failure or control board problem. Ignitor glows but no flame points to gas supply or valve problems.

4. Inspect The Ignitor

Hot Surface Ignitors (HSI) and spark igniters are fragile. HSIs are ceramic and will show visible cracks when bad or will not glow. Spark igniters are visible as a gap where spark forms.

Perform a visual inspection with power removed. For HSIs, a multimeter can test continuity; many HSIs have high resistance, so check manufacturer specs. Replace any cracked or non-glowing ignitor rather than attempting to repair it.

5. Test The Gas Supply And Gas Valve

Confirm the house gas supply is on and other gas appliances work. At the furnace, ensure the gas shutoff valve is open. If the furnace clicks for ignition but no flame appears, the gas valve might not be opening or the gas pressure could be insufficient.

Only trained technicians should measure gas pressure or repair gas valves. If a homeowner suspects a gas supply interruption, call the gas utility or a certified HVAC technician.

6. Clean Or Replace The Flame Sensor

A dirty flame sensor often causes the furnace to light then shut off quickly, or to lock out. Carefully remove the flame sensor and clean it with fine emery cloth or steel wool—do not sand aggressively. Reinstall securely; a loose sensor can cause intermittent contact.

If cleaning does not resolve the issue, replace the flame sensor. This is a common and inexpensive fix.

7. Inspect The Pressure Switch And Venting

The pressure switch verifies the inducer motor and venting are functioning. A blocked vent, bird nest, or disconnected PVC can cause the pressure switch to stay open and prevent ignition. Visual inspection of exhaust and intake pipes is essential.

If the inducer runs but the pressure switch doesn’t close, test the switch tubing for blockage and the switch with a multimeter for continuity when the inducer is running. Replace damaged tubing and faulty switches.

8. Look For Control Board Error Codes

American Standard furnaces often use LED blink codes to indicate faults. Count the flashes or check the control board label for code definitions. Common codes identify issues such as failed ignitor, flame loss, pressure switch faults, or limit switch trips.

Document the code and consult the furnace manual or manufacturer website for the specific meaning and recommended corrective actions.

When To Reset The Furnace And How To Do It

Resetting the furnace can clear temporary lockouts. Turn the thermostat to Off, switch off power to the furnace at the breaker, wait 30 seconds, then restore power and set the thermostat back to Heat. If the furnace cycles through normally, monitor for reoccurrence.

Frequent resets indicate an underlying fault that requires diagnosis and repair rather than repeated resets.

Common Replacement Parts And Typical Costs

Part	Typical Cost Range (Parts Only)
Hot Surface Ignitor	$50–$150
Flame Sensor	$15–$60
Pressure Switch	$40–$120
Gas Valve	$150–$400
Control Board	$120–$500

Labor costs vary by region; expect higher charges in metropolitan areas. For safety-related parts like gas valves, professional installation is highly recommended.

DIY Versus Professional Repair: Guidelines

Homeowners can perform safe tasks like checking thermostats, replacing filters, cleaning flame sensors, and visually inspecting vents and ignitors if comfortable. Use model-specific replacement parts and follow manufacturer instructions.

Call a licensed HVAC technician for gas valve replacement, control board diagnostics, inducer motor repairs, complex electrical tests, or any time gas leaks or combustion issues are suspected. Professionals can also run combustion analysis to ensure safe and efficient operation.

Preventive Maintenance To Avoid Ignition Failures

• Replace air filters every 1–3 months depending on use and filter type.
• Schedule annual furnace inspections by a licensed technician to check ignition components, gas pressure, and venting.
• Keep the furnace area clean and clear of debris; ensure proper airflow around the unit.
• Inspect outdoor intake and exhaust for obstructions seasonally.
• Use a carbon monoxide detector near sleeping areas and regularly test it.

Understanding Error Codes And Manufacturer Support

American Standard furnaces display diagnostic codes via an LED or control panel. Common codes point to ignition failure, flame loss, pressure switch faults, or limit switches. The furnace manual or American Standard dealer resources provide the code definitions and troubleshooting steps.

If warranty coverage is active, contact an authorized dealer for repairs to avoid voiding the warranty. For out-of-warranty units, obtain multiple quotes for major repairs versus replacement.

When Replacement Is A Better Option

Consider replacement if the furnace is older than 15–20 years, repairs are frequent or costly, efficiency is low, or the unit contains discontinued parts. Upgrading to a modern high-efficiency furnace can reduce energy bills and improve reliability.

Evaluate total repair costs vs. replacement quotes, factoring in expected remaining lifespan, energy savings, and available rebates or tax incentives for high-efficiency systems.

Resources And Next Steps

Homeowners should consult the furnace model manual for model-specific procedures and error code tables. Manufacturer websites and authorized American Standard dealers provide support and genuine replacement parts.

If the problem persists after basic troubleshooting, document symptoms, any error codes, and recent maintenance actions to share with an HVAC technician for faster diagnosis.