A modern furnace runs a strict startup sequence, and knowing where the sequence breaks is most of the diagnosis. The thermostat calls, the inducer motor spins up to prove draft through a pressure switch, the hot surface igniter glows, the gas valve opens, the burners light, the flame sensor confirms fire, and only then does the blower deliver heat to the house. In Metairie, LA, the failures cluster at predictable points: a flame sensor coated in oxide that can no longer prove the flame, a hot surface igniter cracked from years of thermal cycling, a pressure switch that will not close because the inducer is weak or the condensate trap on a high-efficiency model has clogged, or a control board with a burned relay. Each one stops the sequence cold, and each one mimics the others from the hallway.
Cooling trouble instead? See AC Repair.
Warning Signs for Furnace Repair
The sooner you notice these red flags, the easier and cheaper the fix. These are the signals our technicians see most often:
- Repeated shutdowns just seconds after the burners light
- A pilot or burner flame that is lazy yellow instead of crisp blue
- Frequent on-off cycling that never reaches the thermostat setting
- Grinding or high-pitched squeals from the blower
- Booming or banging at light-off from delayed ignition
- A fan that keeps running while the registers blow cool air
- Water, rust stains, or black soot around the flue or cabinet
- The igniter glows and clicks, yet no flame ever appears
Don't Wait for a Total Failure
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. If you notice any of these signs, call (504) 531-6049 for a prompt inspection.
