Goodman Furnace 4 Flashes — Open High Limit
Four flashes on many Goodman boards means the high-limit switch opened during a heat call. Like Carrier’s code 33, this is almost always dirty filters, closed registers, or a struggling blower — not a reason to jumper the limit.
Updated July 2026 · 5 min read · United States
Symptoms
- Burners light, then shut down mid-cycle
- LED pattern is 4 flashes (confirm door chart)
- Supply air feels weak or rooms stay cold
Likely causes
- Clogged 1" filter
- Closed bedroom supplies or blocked return
- Blower wheel packed with dust
- Failed limit switch after chronic overheating
What to do
1. Match the flash count to the door sticker
Goodman revisions differ. Confirm 4 flashes = open limit before buying parts.
2. Replace the filter and restore airflow
Use the exact nominal size. If you recently installed a thick MERV-13 in a 1" slot, try MERV-11.
3. Reset and observe one heat cycle
If the furnace completes the cycle, maintain a monthly filter check for the rest of the season.
Stop and call a pro when
- Flashes continue with a clean filter and open ducts
- The heat exchanger shows rust-through or cracks
- You need static-pressure diagnostics
Related guides
- Goodman 3 Flashes — Diagnose Goodman (and Amana) furnace LED 3-flash codes: pressure switch, inducer, and flame-sensing failures — plus the parts that usually fix them.
- Carrier Code 33 — What Carrier furnace error code 33 means, how to safely check airflow and the limit switch, and which parts or filters usually clear the fault.
- Replace 20×25×1 Filter — Step-by-step 20x25x1 furnace filter replacement with MERV tips and multipack product links for the exact size.
- Carrier Code 13 — Carrier/Bryant code 13 is a limit lockout after repeated trips. Fix airflow first, then check filters or capacitors.
FAQ
Can I tape over the limit switch?
Never. Bypassing a limit can crack the heat exchanger and create a carbon monoxide hazard.
Need a licensed tech instead?
If the guide says to stop — or the part swap did not clear the fault — get free quotes from licensed local HVAC contractors.
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