Furnace flashing 11 times: what 11 flashes means
The number of flashes on a furnace control board is not a standard. Every manufacturer assigns its own meanings, and 11 flashes means something different across the 3 control families below.
On an Armstrong it is pressure switch stuck closed before the inducer started, on a Goodman it is limit switch open due to blower failure, and on a York it is limit switch open more than five minutes — blower failure.
These three don't share a cause; eleven flashes is three unrelated faults that happen to line up on the same number. Identify the brand before acting on any of them.
11 flashes, by manufacturer
| Furnace brand | What 11 means there |
|---|---|
| Armstrong 11 flashes | Pressure switch stuck closed before the inducer started |
| Goodman 11 red flashes | Limit switch open due to blower failure |
| York 11 red flashes | Limit switch open more than five minutes — blower failure |
Before counting again
A blink with no pause at all — nothing resembling a counted run of eleven — is a heartbeat, not a fault code, and it just confirms the board has power and no complaint. Every non-fault pattern, sorted by brand, is listed elsewhere.
Finding out which brand you have
Don't trust the thermostat for the brand name — the rating plate bolted inside the cabinet has it, and it can differ from the company that actually manufactured the control board. Reading a furnace fault code explains where that plate sits and what to do if your display shows digits instead of a flash count.
- Goodman — also Amana
- Carrier — also Bryant, Payne
- Trane — also American Standard
- Lennox
- York — also Luxaire, Coleman
- Rheem — also Ruud, Weather King
- Heil — also Tempstar, Comfortmaker, Arcoaire, KeepRite
- Armstrong — also AirEase, Concord, Ducane
Other flash counts
- One flash
- 2 flashes
- 3 flashes
- 4 flashes
- 5 flashes
- 6 flashes
- 7 flashes
- 8 flashes
- 9 flashes
- 10 flashes
- 12 flashes
What the fix costs
A diagnosis that lands on a failed part comes with a price tag — check what control board replacement typically costs, or the general furnace repair cost guide for service-call rates.
What 11 flashes usually points to
11 flashes is a blower or airflow fault on Goodman and York — a limit switch that opened because the blower failed to move air — and a pressure switch stuck closed before the inducer even started on Armstrong. On the boards reporting the limit-switch version, the blower motor or its capacitor is the part to check first, not the limit switch, which is only reporting the effect. That is a different failure than 10 flashes' gas-valve theme, and one step short of 12 flashes' ignition-hardware group, the last count these three brands document.
Sources
The eleven-flash entries above are sourced from the manufacturer manuals linked on their code pages:
- Allied Air Enterprises — A80UH1E and 80G1UHE Installation Instructions 507330-03, Table 7: Diagnostic Codes for -02 Control
- Goodman Manufacturing — Diagnostic Code Identification System (model-specific fault code lookup)
- Johnson Controls Unitary Products technical service letter ST-045-09 — York UTEC furnace boards, with the previous White-Rodgers Emerson code table reproduced for comparison