Quick answer
6 flashes on a Goodman furnace means an open rollout temperature limit switch; Goodman's chart also lists a blown control-board fuse under this code. Rollout means flame left the burner area, so do not keep running it. Turn the furnace off at the switch, check the outside vent pipes for a blockage, do not press the rollout reset, and call a technician now.
Treat 6 flashes on a Goodman furnace as a stop sign: it means the rollout temperature limit switch is open. That switch is a heat sensor beside the burners, and it trips when flame or hot gas comes out of the burner area instead of being drawn into the heat exchanger. Goodman's diagnostic chart also lists a blown fuse on the integrated control under the same code. Boards differ, so confirm against the chart inside your furnace door, which overrides anything written here.
Is it safe to run a Goodman furnace showing 6 flashes?
No. Rollout means flame left the burner area, and the switch is manual-reset on purpose, so that someone finds out why before the furnace runs again. Pressing the reset without that answer relights a furnace that has already shown it cannot contain its flame. The risks are scorched wiring, a fire inside the cabinet, and combustion gases, carbon monoxide among them, entering the house.
What to do right now
- Turn the furnace off at the wall switch beside it.
- Go outside and check that the vent pipes are not blocked by snow, ice, leaves or a nest. Clear what you can reach by hand, and leave the furnace off even if you find and remove a blockage.
- Do not press the rollout reset button, and do not open the burner compartment.
- Test your carbon monoxide alarms. Ontario's Hawkins-Gignac Act requires working alarms in homes with fuel-burning appliances; if one sounds or anyone feels unwell, get everyone out and call 911.
- If you smell gas, leave the house and follow the steps for a gas smell from outside.
- Call for service and say the furnace is showing a rollout code.
Why flame rolls out of a Goodman burner box
- A blocked flue or air inlet pipe. With the exhaust path choked, combustion gases have nowhere to go and flame backs out at the burners.
- A failed induced-draft blower. The fan that pulls flame through the heat exchanger has stopped or slowed.
- Misaligned burners. A burner knocked out of line sends flame against the edge of the heat exchanger opening instead of into it.
- A short in the 24 V control circuit. This is the blown-fuse side of the code: shorted low-voltage wiring takes out the fuse on the board, and no flame was involved.
- A faulty rollout limit, or loose wiring to it. Possible, but it is the conclusion a technician reaches last, after proving the flame stays where it belongs.
A technician also inspects the heat exchanger, because a blocked or damaged exchanger disturbs the flame the way a blocked vent does. The pattern behind repeat trips is covered in why a furnace rollout switch keeps tripping, and the part is explained in the rollout switch glossary entry.
What a technician does before resetting the rollout switch
The visit works backwards from the flame. The technician checks the vent and intake from end to end, runs the inducer and measures the draft, inspects the burners and the heat exchanger, and looks for scorch marks around the burner box. Only when the cause is found and corrected is the switch reset, and the furnace is then watched through a full heating cycle.
Expect questions about what happened before the code appeared: a boom at ignition, a smell of exhaust, soot or discolouration on the front of the furnace, or recent work on the vent. Those details point to the cause faster than the switch does.
If the fuse is the cause, the job is finding the short, not feeding the board new fuses. Never fit a larger fuse than the one the board was built with: the fuse is there to protect the transformer and the control.
- Diagnostic visit: $90–$150, which goes toward the repair if you proceed.
- Draft inducer motor: $400–$900.
- Control board, if a short has damaged it: $500–$1,200.
- Heat exchanger replacement: $1,500–$3,000, a figure that on an older furnace tips the decision toward a new unit.
- Vent or burner corrections: quoted in writing once the cause is known.
A rollout code is a call-now code. ZK Mechanical answers its emergency line around the clock with no after-hours surcharge, and gas repairs are done by TSSA-licensed technicians. Call (647) 801-1252 for furnace repair, or send a message if the furnace is safely off and the house has other heat. Other Goodman codes are in the Goodman furnace error code guide.