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 Wilmington, NC, 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.
Warning Signs for Furnace Repair
Spotting the early warning signs lets you act before the problem gets expensive. Keep an eye out for the following clues:
- Squealing or grinding from the blower compartment
- The igniter glows and clicks, yet no flame ever appears
- Flames that start, last a few seconds, and go out again and again
- A furnace that shuts off every few minutes before the house warms up
- Yellow, wavering burner flames where they should be sharp blue
- A bang or boom when the burners ignite late
- Water, rust stains, or black soot around the flue or cabinet
- The blower runs constantly but the air never warms
Early Action Saves Money
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. Call (910) 266-6556 at the first sign of trouble.
