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 Indianapolis, IN, the failures cluster at predictable points: an oxide-coated flame sensor, 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.
When the AC quits in summer, see AC Repair.
Signs You Need Furnace Repair in Indianapolis
The sooner you notice these red flags, the easier and cheaper the fix. Watch for these telltale signs:
- Grinding or high-pitched squeals from the blower
- Repeated shutdowns just seconds after the burners light
- Short cycling every few minutes without reaching the setpoint
- Yellow, wavering burner flames where they should be sharp blue
- Booming or banging at light-off from delayed ignition
- Rust streaks, soot, or water around the cabinet or flue
- The igniter glows and clicks, yet no flame ever appears
- A fan that keeps running while the registers blow cool air
Early Action Saves Money
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. Call (317) 206-4679 at the first sign of trouble.
