Heil Furnace Code 2: What It Means & How to Fix It
Compiled & reviewed by the HVAC Flash Codes editorial team · Updated 2026-06-25 · confidence: high
🟢 Often homeowner-fixable
What does Heil furnace code 2 mean?
Pressure switch did not open — the control sensed the pressure switch was still closed when it should have been open. Most often caused by Obstructed pressure tubing.
What your furnace LED does. The diagnostic light blinks 2 flashes, pause, repeat — that pattern is Heil furnace code 2.
What Heil furnace code 2 means
Pressure switch did not open — the control sensed the pressure switch was still closed when it should have been open.
Common causes
Obstructed pressure tubing
Pressure switch stuck closed
Homeowner-safe steps to try
Check that the outdoor intake/exhaust terminations are clear of snow, leaves, ice, or debris
Set the thermostat OFF, power the furnace off at the breaker for about a minute, then restore to retry
If the code persists, leave the diagnosis to a technician — the tubing and switch aren't homeowner-serviceable
When to call a licensed HVAC technician
If the basic checks below don't clear the code, the fault recurs, or anything involves the gas valve, burners, flame sensor or wiring, stop and book a licensed HVAC technician. Repairs to the combustion or gas system are not DIY.
⚠️ Safety first. Gas furnaces burn fuel and produce combustion gases. If you ever smell gas (a rotten-egg or sulfur odor), hear hissing, or your carbon-monoxide alarm sounds, do not touch light switches, thermostats, or the furnace — leave the home immediately and call your gas utility's emergency line or 911 from outside. Homeowners should limit themselves to simple, safe steps: setting the thermostat, checking and replacing the air filter, confirming the furnace switch and breaker are on, keeping supply registers and return grilles open, and clearing snow, ice, or debris from outdoor vent and intake terminations. Never bypass, jumper, or reset safety switches (limit, flame-rollout, or pressure switches), never open the gas valve or burner compartment, and never attempt combustion, electrical, or control-board repairs yourself. Error codes point toward a problem but are not a substitute for proper diagnosis — when in doubt, turn the system off and call a licensed HVAC technician. Keep working carbon-monoxide detectors on every level of your home.
When to call a pro: Call a licensed HVAC technician if the code repeats after clearing the vents and power-cycling — the pressure switch or its tubing needs professional service. If you smell gas, leave immediately and call your gas utility or 911 from outside.
Heil furnace code 2 FAQ
What does Heil furnace code 2 mean?
Pressure switch did not open — the control sensed the pressure switch was still closed when it should have been open.
What causes Heil furnace code 2?
Common causes: Obstructed pressure tubing; Pressure switch stuck closed.
Can I fix Heil furnace code 2 myself?
You can safely try: Check that the outdoor intake/exhaust terminations are clear of snow, leaves, ice, or debris; Set the thermostat OFF, power the furnace off at the breaker for about a minute, then restore to retry; If the code persists, leave the diagnosis to a technician — the tubing and switch aren't homeowner-serviceable. Call a licensed HVAC technician if the code repeats after clearing the vents and power-cycling — the pressure switch or its tubing needs professional service. If you smell gas, leave immediately and call your gas utility or 911 from outside.
Sources: shareddocs.com. General information for homeowners, not professional advice — confirm against your furnace's manual and a licensed technician.