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 Mountain View, CA, 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.
When the AC quits in summer, see AC Repair.
When to Call for Furnace Repair in Mountain View
Catching these issues early helps you avoid costly problems. Watch for these telltale signs:
- Squealing or grinding from the blower compartment
- Clicking and a glowing igniter with no burner flame
- Booming or banging at light-off from delayed ignition
- Short cycling every few minutes without reaching the setpoint
- Yellow, wavering burner flames where they should be sharp blue
- Air moving through the vents that never gets warm
- Flames that start, last a few seconds, and go out again and again
- Soot, rust, or moisture near the furnace cabinet or vent pipe
Early Action Saves Money
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. Call (650) 220-0820 at the first sign of trouble.
