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 College Station, TX, 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
Recognizing the warning signs early can save you time and money. Watch for these telltale signs:
- Short cycling every few minutes without reaching the setpoint
- Booming or banging at light-off from delayed ignition
- Grinding or high-pitched squeals from the blower
- Air moving through the vents that never gets warm
- A flame that burns soft and yellow rather than steady blue
- Soot, rust, or moisture near the furnace cabinet or vent pipe
- Clicking and a glowing igniter with no burner flame
- Repeated shutdowns just seconds after the burners light
Early Action Saves Money
Most HVAC failures start small, a weak capacitor, a squealing blower, a system that runs a little longer each week. Call (979) 200-4285 at the first sign of trouble.
