How to read Carrier furnace LED codes

What this error means

Carrier status codes are two-digit numbers blinked through the sight glass in the blower door: SHORT flashes are the tens digit, LONG flashes are the ones digit — so short-short-short then long = Code 31. Interrupting power for ~30 seconds clears the code; it comes right back if the fault is still present. Same scheme on Bryant and Payne (same manufacturer platform).

Symptoms

• Amber/yellow LED blinking a repeating pattern
• Furnace not running normally

Try this first (safe DIY steps)

1. Watch the LED through the sight glass and count: short flashes = first digit, long flashes = second digit
2. Write the code down before power cycling — you'll want it for the lookup (and for any technician)
3. Power off 30 seconds, restore, and note whether the code returns
4. Look up the code in our Carrier guides (31, 33, 34, 13 cover the most common events)

Safety: power off before any physical intervention. Never bypass covers or interlocks — fuser areas run hot enough to burn.

When to call a technician

Codes that return after a power cycle mean a real fault — bring the code number to the service call; it meaningfully speeds up (and cheapens) diagnosis.