From the hallway, a furnace that will not heat looks the same no matter what broke. Inside the cabinet, though, the sequence is strict: inducer on, pressure switch closed, igniter glowing, gas valve open, burners lit, flame proven, and finally the blower moving heat through the ducts. Diagnosis is mostly a matter of finding where that chain breaks. In Marietta homes, it tends to be the same handful of culprits: a flame sensor coated in oxide, a hot surface igniter cracked by thermal cycling, a pressure switch held open by a tired inducer or a plugged condensate trap, or a control board with a burned relay.
Cooling trouble instead? See AC Repair.
Warning Signs for Furnace Repair
Recognizing the warning signs early can save you time and money. Watch for these telltale signs:
- A bang or boom when the burners ignite late
- Yellow, wavering burner flames where they should be sharp blue
- Repeated shutdowns just seconds after the burners light
- Rust streaks, soot, or water around the cabinet or flue
- The igniter glows and clicks, yet no flame ever appears
- Squealing or grinding from the blower compartment
- A furnace that shuts off every few minutes before the house warms up
- A fan that keeps running while the registers blow cool air
Early Action Saves Money
A failing capacitor, clogged condensate drain, or dirty flame sensor rarely fixes itself and usually gets more expensive to address the longer it runs. If you notice any of these signs, call (770) 202-3453 for a prompt inspection.
