Why Your Heil Furnace Is Not Igniting and How to Fix It

When a Heil furnace is not igniting, it can leave a household cold and uncomfortable. This common issue can stem from various mechanical or electrical problems. Understanding the causes and troubleshooting steps will help homeowners restore warmth efficiently and safely. This article explores the main reasons for ignition failure, diagnostics, and practical solutions specifically tailored to Heil furnaces.

Cause	Possible Symptoms	Suggested Fix
Thermostat Issues	No call for heat, furnace does not start	Check settings, replace batteries, recalibrate or replace thermostat
Ignitor Failure	Clicking sound, no flame	Test ignitor with multimeter, replace if faulty
Gas Supply Problem	Gas smell, no ignition	Inspect gas valve, ensure gas supply and pressure
Flame Sensor Dirt	Furnace lights then shuts off	Clean flame sensor with fine sandpaper
Blocked Air Intake/Exhaust	System shuts down for safety	Clear blockages from vents and pipes

Common Reasons a Heil Furnace Fails to Ignite

When a Heil furnace doesn’t ignite, it indicates an interrupt in the essential ignition sequence. Several key components are involved in this critical process, including the thermostat, ignitor, gas valve, and flame sensor. Any malfunction in these parts can prevent ignition.

Thermostat issues can be a simple cause—incorrect temperature settings or power problems may prevent the furnace from receiving the heat request. Similarly, the ignitor can fail due to wear, causing no spark or glow to light the burner.

Issues with the gas supply are common, such as closed valves or low pressure, stopping fuel from reaching the burners. Dirt or corrosion on the flame sensor can cause the furnace to ignite momentarily but then shut down for safety reasons. Blocked air intake or exhaust pipes can also trigger safety switches that prevent ignition.

Identifying and Testing the Thermostat

The thermostat is the furnace’s command center. When it fails, the furnace will not ignite. Homeowners should first check if the thermostat is set to “heat” and if the temperature setting is above the current room temperature.

Replace the batteries in battery-operated models or reset programmable thermostats to factory settings if needed. Testing the thermostat functionality using a multimeter or calling a professional can confirm whether replacement is necessary.

Inspecting the Furnace Ignitor

The ignitor is the part responsible for lighting the furnace burner. Heil furnaces typically use a hot surface ignitor or spark ignitor. Signs of a faulty ignitor include a clicking sound without ignition or no sound at all.

Visual inspection for cracks or wear is essential, along with testing electrical continuity with a multimeter. A damaged or non-responsive ignitor usually requires replacement. Always allow the furnace to cool before attempting any repairs.

Ensuring Proper Gas Supply and Burner Operation

Gas supply issues are often overlooked but crucial. Make sure the main gas valve is open and the gas line to the furnace is free of leaks or damage. Gas pressure must meet manufacturer specifications for proper ignition.

Burner assembly should be checked for dirt, rust, or blockages. Dirty burners or clogged orifices can hinder gas flow, preventing ignition. Periodic professional maintenance ensures gas flow integrity and safety.

Cleaning and Maintaining the Flame Sensor

The flame sensor detects the presence of a flame and signals the furnace to keep running. When dirty, the sensor falsely detects no flame and shuts the system down shortly after ignition.

To clean, gently rub the metal rod with fine-grit sandpaper or a soft cloth to remove buildup. Avoid aggressive scrubbing or bending the sensor. This simple maintenance step often resolves furnace shutdowns after ignition.

Checking Air Intake and Exhaust Vents

Proper airflow is critical for combustion and safety. Blocked or restricted air intake or exhaust vents can cause a furnace to fail ignition as the safety switch engages.

Inspect outdoor vent caps, pipes, and air intake areas for debris such as leaves, nests, or ice buildup. Clear all obstructions to ensure free airflow. Regular inspections help prevent airflow-related ignition issues.

Troubleshooting Common Error Codes

Many modern Heil furnaces feature diagnostic LED lights or error codes visible on the control board. Refer to the furnace manual to interpret blinking codes, as they pinpoint specific faults like ignitor failure or flame sensor errors.

Using error codes can save troubleshooting time and assist technicians in quickly resolving ignition problems.

When to Call a Professional HVAC Technician

While some ignition issues can be addressed by homeowners, problems involving gas lines, electrical components, or complex diagnostics should be handled by licensed HVAC professionals.

Safety is paramount when working with gas appliances. Early professional intervention prevents damage, ensures compliance with local codes, and maintains system efficiency.

Routine Furnace Maintenance to Prevent Ignition Failures

Regular maintenance greatly reduces ignition problems and extends the lifespan of a Heil furnace. Recommended tasks include:

• Annual professional inspections and tune-ups
• Replacing air filters monthly or quarterly
• Cleaning flame sensors and burners annually
• Checking and clearing air intakes and exhaust vents regularly
• Testing thermostat function seasonally

Summary of Troubleshooting Steps

Step	Action	Tools Needed
1	Verify thermostat settings and power	None or screwdriver for thermostat access
2	Inspect and test ignitor for damage	Multimeter, screwdrivers
3	Check gas valve and supply lines	Professional tools recommended
4	Clean flame sensor carefully	Fine sandpaper or cloth
5	Clear air intake and exhaust vents	Gloves, flashlight
6	Check furnace error codes (if applicable)	Owner’s manual
7	Call HVAC technician if unresolved	Contact information for local service