Furnace Error Codes by Brand

LED blink codes for Carrier, Trane, Rheem, Goodman, and Lennox furnaces. What they mean and what to do.

Before You Look Up Codes#

Check and replace your air filter first
Make sure vents aren't blocked
Verify gas supply is on

Carrier / Bryant / Payne#

Blinks	Meaning	Action
Steady ON	Normal standby	None needed
1	Ignition failure	Reset power, call if persists
2	Pressure switch stuck open	Check vents for blockage
3	Limit switch open	Replace filter! Check airflow
4	Pressure switch stuck closed	Call technician
6	Reversed polarity	Call electrician

Trane / American Standard#

Blinks	Meaning	Action
Slow steady	Normal	None needed
2	Ignition/flame sensor	Call technician
3	Pressure switch	Check vents for blockage
4	Overheating	Replace filter!
5	Gas valve issue	Call technician

Rheem / Ruud#

Blinks	Meaning	Action
1	Soft lockout	Will retry automatically
2	Pressure switch open	Check vents
3	Limit switch open	Replace filter!
4	Pressure switch stuck	Call technician

Goodman / Amana#

Blinks	Meaning	Action
Constant	Reversed polarity	Call electrician
1	Ignition lockout	Reset, call if persists
2	Pressure switch open	Check vents
3	Pressure switch stuck	Call technician
4	Limit/rollout switch	Replace filter, call if persists

Lennox#

Lennox uses two LEDs (red and green). Both flashing slowly together = normal operation. Check the code chart inside your furnace panel for specific patterns.

Universal Reset Procedure#

Turn off furnace power (switch or breaker)
Wait 20-30 seconds
Turn power back on
If code returns, call a technician