York Furnace 8 red flashes: What It Means & How to Fix It
Compiled & reviewed by the HVAC Flash Codes editorial team · Updated 2026-06-25 · confidence: high
⛔ Stop — call a licensed pro
What does York furnace 8 red flashes mean?
Flame was lost five times (four recycles) during the heating cycle. The furnace locks out for one hour and then restarts. Most often caused by Low gas pressure.
What your furnace LED does. The diagnostic light blinks 8 flashes, pause, repeat — that pattern is York furnace 8 red flashes.
What York furnace 8 red flashes means
Flame was lost five times (four recycles) during the heating cycle. The furnace locks out for one hour and then restarts.
Common causes
Low gas pressure
A dirty or faulty flame sensor
A faulty gas valve
Homeowner-safe steps to try
Note the code; allow the one-hour lockout to reset or cycle power off/on once
Confirm other gas appliances in the home have gas supply
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 to inspect the flame sensor, gas pressure, and gas valve. Do not service the gas valve or burners. If you smell gas, leave and call your gas utility or 911 from outside.
York furnace 8 red flashes FAQ
What does York furnace 8 red flashes mean?
Flame was lost five times (four recycles) during the heating cycle. The furnace locks out for one hour and then restarts.
What causes York furnace 8 red flashes?
Common causes: Low gas pressure; A dirty or faulty flame sensor; A faulty gas valve.
Can I fix York furnace 8 red flashes myself?
You can safely try: Note the code; allow the one-hour lockout to reset or cycle power off/on once; Confirm other gas appliances in the home have gas supply. Call a licensed HVAC technician to inspect the flame sensor, gas pressure, and gas valve. Do not service the gas valve or burners. If you smell gas, leave and call your gas utility or 911 from outside.