York Furnace: 8 Flashes
A York furnace LED pattern starting with 8 flashes matches 2 documented codes: 8 red flashes, 8 red flashes (YP9C modulating). Watch the full pattern (short vs. long flashes) to tell them apart — all 2 are explained below.
Code 8 red flashes: The flame was lost five times
The flame was lost five times (four recycles) during one heating cycle. The furnace locks out for one hour and then restarts.
Manual wording: “8 RED FLASHES: This fault is indicated if the flame is lost five times (four recycles) during the heating cycle. Check for low gas pressure, dirty or faulty flame sensor or faulty gas valve.”
Documented for: TG8S, TG9S, TM9E, TM9X, TM8X, TM9T, TM8T, TM9V, TM8Y, TM9Y
Likely causes, most common first
- Low gas pressure
- Dirty or faulty flame sensor
- Faulty gas valve
What you can safely check yourself
- Check that other gas appliances in the house still work
- Replace a dirty air filter
- Check the outside vent and intake pipes for blockage
When to call a technician
Flame sensor cleaning and gas pressure checks are done with the burners running and require a manometer. Call a technician.
A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Installation Manual - Single Stage PSC Residential Gas Furnaces, TG9S and GG9S Series (95.5% AFUE Multi-position), 1083287-UIM-A-0114 (Johnson Controls Unitary Products (York), TG9S*MP, GG9S*MP single-stage PSC 95.5% AFUE gas furnaces) · checked 2026-08-25
- Installation Manual - Single Stage PSC Residential Gas Furnaces, TG8S*MP / TGLS*MP / GG8S*MP / GGLS*MP (80% AFUE Multi-position / Standard Low NOx), 998491-UIM-B-1013 (Johnson Controls Unitary Products (York), TG8S*MP, TGLS*MP, GG8S*MP, GGLS*MP 80% AFUE single-stage gas furnaces) · checked 2026-08-25
- Installation Manual - Single Stage ECM Residential Gas Furnaces, TM9E Series (95% AFUE Multi-position), 1083163-UIM-A-0214 (Johnson Controls Unitary Products (York), TM9E*MP single-stage ECM 95% AFUE gas furnaces) · checked 2026-08-25
- Installation Manual - Two Stage Variable Speed ECM Residential Gas Furnaces, TM9V Series (96% AFUE Multi-position), 1083294-UIM-A-0114 (Johnson Controls Unitary Products (York), TM9V*MP two-stage variable-speed ECM 96% AFUE gas furnaces) · checked 2026-08-25
Code 8 red flashes (YP9C modulating): Lockout due to too many flame recycles - the flame was lost five times during a single heating cycle
Lockout due to too many flame recycles - the flame was lost five times during a single heating cycle. The control locks out for one hour, then tries again.
Manual wording: “Eight Red Flashes - Lockout due to too many flame recycles. This flash code occurs if flame is lost five times during a single heating cycle.”
Documented for: YP9C, YPLC modulating furnaces
Likely causes, most common first
- Faulty gas valve
- Low gas pressure
- Dirty flame sensor
What you can safely check yourself
- Check that other gas appliances in the house still work
- Replace a dirty air filter
When to call a technician
Gas pressure and flame sensor checks require a manometer and live-burner access. Call a technician.
A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- Installation Manual - Modulating ECM Residential Gas Furnace with ECM Motor, Models YP9C*C / TP9C*C / CP9C*C / LP9C*C (Up to 98% Modulating Multi-position), 1083292-UIM-A-0114 (Johnson Controls Unitary Products (York), YP9C*C (York Affinity modulating), and the identical TP9C / CP9C / LP9C chassis) · checked 2026-08-25