Coleman Furnace: 10 Flashes
A Coleman furnace LED pattern starting with 10 flashes matches 2 documented codes: 10 red flashes, 10 red flashes (CP9C Echelon modulating). Watch the full pattern (short vs. long flashes) to tell them apart — all 2 are explained below.
Code 10 red flashes: The gas valve is energized with no call for heat
The gas valve is energized with no call for heat. The main blower and inducer will run and no ignition sequence starts as long as the condition exists.
Manual wording: “10 RED FLASHES: Gas valve energized with no call for heat. The main blower and inducer blower will run and no ignition sequence will be started as long as this condition exists. Check gas valve and gas valve wiring.”
Documented for: TG8S, TGLS, TG9S, TM8X, TMLX, TM9X, TM8T, TM9T, TM8V, TM9V
Likely causes, most common first
- Faulty gas valve
- Gas valve wiring fault
What you can safely check yourself
- If you smell gas, leave the house and call the gas utility from outside
When to call a technician
The gas valve is being powered when it should not be. Call a licensed technician immediately - do not keep operating the furnace.
A Coleman furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Installation Manual - Residential Gas Furnace, Models TG9S*MP, GG9S*MP (95.5% AFUE Single Stage Multi-position), 364861-UIM-G-1211 (Johnson Controls Unitary Products (Coleman), TG9S*MP, GG9S*MP 95.5% AFUE single-stage multi-position gas furnaces) · checked 2026-08-25
- Installation Manual - Residential Gas Furnace, Models TG8S*MP, TGLS*MP, GG8S*MP, GGLS*MP (Single Stage Multi-position / Low NOx), 356485-UIM-G-1211 (Johnson Controls Unitary Products (Coleman), TG8S*MP, TGLS*MP, GG8S*MP, GGLS*MP 80% AFUE single-stage gas furnaces) · checked 2026-08-25
- Installation Manual - Residential Gas Furnace, Models TM8X*MP, TMLX*MP (Single Stage Multi-position / Low NOx with High-Efficiency Motors), 437642-UIM-F-1211 (Johnson Controls Unitary Products (Coleman), TM8X*MP, TMLX*MP 80% AFUE single-stage gas furnaces with high-efficiency motors) · checked 2026-08-25
- Installation Manual - Residential Gas Furnace, Models TM9V*MP (Two Stage Variable Speed ECM), 701379-UIM-B-1211 (Johnson Controls Unitary Products (Coleman), TM9V*MP two-stage variable-speed ECM gas furnaces) · checked 2026-08-25
Code 10 red flashes (CP9C Echelon modulating): Gas valve circuit shorted
Gas valve circuit shorted.
Manual wording: “Ten Red Flashes - Gas valve circuit shorted. Check gas valve wiring. If correct, replace gas valve.”
Documented for: CP9C Echelon modulating furnaces
Likely causes, most common first
- Shorted gas valve wiring
- Failed gas valve
What you can safely check yourself
- If you smell gas, leave the house and call the gas utility from outside
When to call a technician
A shorted gas valve circuit is a gas-safety fault. Call a licensed technician and do not keep cycling the furnace.
A Coleman furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- Installation Manual - Residential Gas Furnace with ECM Motor, Models TP9C*C, YP9C*C, CP9C*C, LP9C*C (Up to 98% Modulating Multi-position), 681292-UIM-B-1211 (Johnson Controls Unitary Products (Coleman), CP9C*C Coleman Echelon modulating gas furnace (manual also covers the identical TP9C, YP9C and LP9C chassis)) · checked 2026-08-25
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