From the hallway, a furnace that will not heat looks the same no matter what broke. Inside the cabinet, though, everything happens in a strict order: inducer on, pressure switch closed, igniter glowing, gas valve open, burners lit, flame proven, and finally the blower sending heat through the house. Most of the diagnosis comes down to finding the broken link. In Louisville 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.
For air conditioning breakdowns, see AC Repair.
Warning Signs for Furnace Repair
Catching these issues early helps you avoid costly problems. These are the signals our technicians see most often:
- A fan that keeps running while the registers blow cool air
- Repeated shutdowns just seconds after the burners light
- A furnace that shuts off every few minutes before the house warms up
- A flame that burns soft and yellow rather than steady blue
- Rust streaks, soot, or water around the cabinet or flue
- Grinding or high-pitched squeals from the blower
- Clicking and a glowing igniter with no burner flame
- Booming or banging at light-off from delayed ignition
Don't Wait for a Total Failure
A failing capacitor, clogged condensate drain, or dirty flame sensor rarely fixes itself and usually gets more expensive to address the longer it runs. Call (502) 844-8263 at the first sign of trouble.
