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 Hammond, IN, 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
Spotting the early warning signs lets you act before the problem gets expensive. Keep an eye out for the following clues:
- Loud booms at startup caused by delayed ignition
- The igniter glows and clicks, yet no flame ever appears
- Squeals, scrapes, or grinding noises behind the blower door
- Repeated shutdowns just seconds after the burners light
- Soot, rust, or moisture near the furnace cabinet or vent pipe
- A fan that keeps running while the registers blow cool air
- Short cycling every few minutes without reaching the setpoint
- A pilot or burner flame that is lazy yellow instead of crisp blue
Don't Wait for a Total Failure
Most HVAC failures start small, a weak capacitor, a squealing blower, a system that runs a little longer each week. Call (219) 202-9124 at the first sign of trouble.
