Turn the furnace off and do not reset it. If you smell gas, leave the building without operating switches and contact the gas utility or emergency services from outside.
What does Comfortmaker code 8 Flash mean?
Comfortmaker furnace code 8 Flash means the control entered permanent gas-heat lockout after detecting a gas-valve relay or wiring fault on the supported control family. Confirm the model number and diagnostic chart inside the furnace door before replacing parts.
What causes Comfortmaker code 8 Flash?
- A gas valve leaking or stuck open
- A shorted flame-sensing circuit
- A failed integrated control board
Can I troubleshoot Comfortmaker code 8 Flash?
Turn the furnace off and do not reset it. If you smell gas, leave the building without operating switches and contact the gas utility or emergency services from outside.
How much does Comfortmaker code 8 Flash cost to fix?
A gas valve replacement typically costs between $300 and $1,000 nationally.
When should I call a technician?
Turn the furnace off and call a licensed technician immediately to test the gas valve and flame-proving circuit.
Sources and model scope
Fault codes vary by model and control board. Confirm the diagnostic chart inside your furnace panel or the official manual before acting.
Scope used here: ICP control boards covered by document 44001202103 and using its 2–10 flash table.
- International Comfort Products: Furnace Control Board Diagnostic Codes
44001202103 · ICP furnace control boards covered by document 44001202103; confirm the control-board label and door chart.
Compiled by Warmlo Editorial · Reviewed August 2026
This is general information, not professional advice. Gas, electrical, and combustion repairs can be dangerous — when in doubt, call a licensed technician.