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 Nampa, ID, 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.
For air conditioning breakdowns, see AC Repair.
Warning Signs for Furnace Repair
The sooner you notice these red flags, the easier and cheaper the fix. These are the signals our technicians see most often:
- A bang or boom when the burners ignite late
- Rust streaks, soot, or water around the cabinet or flue
- The blower runs constantly but the air never warms
- A furnace that shuts off every few minutes before the house warms up
- Grinding or high-pitched squeals from the blower
- Burners light, run a few seconds, then shut down repeatedly
- Clicking and a glowing igniter with no burner flame
- A pilot or burner flame that is lazy yellow instead of crisp blue
Early Action Saves Money
Most HVAC failures start small, a weak capacitor, a squealing blower, a system that runs a little longer each week. At the first hint of a problem, call (208) 208-1825 for a fast inspection.
