On the current two-stage chart, 5 red flashes is the escalation of the 4-flash limit code: the limit and rollout circuit has now been open for 15 minutes, or the control board's fuse is open, or the rollout switch is open. A furnace does not arrive at this code from a dirty filter alone — it arrives by overheating and staying overheated, or by a flame-safety switch doing its job.
On the older single-LED board, 5 flashes is arguably worse: flame detected with the gas valve closed, with miswiring listed as the probable cause. A furnace that believes it sees flame while its gas valve is shut is not a reset-and-watch situation on any board.
5 red flashes: Limit and rollout circuit open for 15 minutes — or an open control board fuse / rollout switch
Safety stop — furnace off, call a technician
This is the 4-flash problem that would not clear, escalated. By the time a board shows 5, it has been open a quarter of an hour.
From the table: Red-LED chart — two-stage 96% furnaces — source: Goodman GCEC960803BN Installation Instructions, Troubleshooting Chart, pp. 55-56 (read the document, fetched 2026-10-30). Covers: GMEC96 / GCEC96 and their Amana twins — the current two-stage condensing furnaces with a green/amber/red LED trio on the board.
What to actually do
Turn the furnace off at the switch and leave it off. If the open switch is the rollout, understand what it reported: flame rolled out of the burner compartment instead of drawing into the heat exchanger. Goodman's own manual lists restricted or blocked flue passages, a blocked or cracked heat exchanger, a failed inducer, or insufficient combustion air. None of those are filter problems. Call a licensed technician and tell them the code and the board type — it shortens the visit.
Safety stop — furnace off, call a technician — the safe list:
- Turn the furnace off at its power switch and leave it off.
- This code means the control thinks flame or gas is present when it should not be, or that a flame-safety switch has opened. Resetting it is not a fix.
- Call a licensed HVAC technician. If you smell gas at any point: leave the house and call your gas utility or 911 from outside.
The two rules that outrank everything on this page.
1. Smell gas? Stop reading. Leave the house and call your gas utility or 911 from outside. No code is worth diagnosing through a gas smell.
2. Never bypass a safety switch — no jumping a pressure switch, no taping a limit, no propping a rollout. Those switches are the only thing between a furnace fault and a fire or carbon-monoxide problem. This library explains codes; it does not teach repairs inside the cabinet.
One honesty note before the tables: codes change between control boards, sometimes inside the same brand and the same decade. Every table below names the board and the manual it was transcribed from. The chart glued inside your own blower door is the final word for your furnace — if it disagrees with this page, believe the door.