Every time your thermostat calls for heat, the furnace works through a fixed checklist. The inducer motor starts and proves draft by closing a pressure switch, the hot surface igniter heats up, the gas valve opens, the burners light, and the flame sensor confirms there is fire. Only after all of that does the blower begin sending warm air into the house. Finding the step that fails is most of the job. Around Santa Barbara, CA, the usual failure points are an oxide-coated flame sensor, an igniter cracked by years of heating and cooling, a pressure switch that stays open because of a weak inducer or a clogged condensate trap on a high-efficiency unit, and control boards with burned relays. Any one of them halts the startup, and from the hallway they all look alike.
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. Watch for these telltale signs:
- Air moving through the vents that never gets warm
- Rust streaks, soot, or water around the cabinet or flue
- Frequent on-off cycling that never reaches the thermostat setting
- Booming or banging at light-off from delayed ignition
- Burners light, run a few seconds, then shut down repeatedly
- Grinding or high-pitched squeals from the blower
- A flame that burns soft and yellow rather than steady blue
- The furnace clicks and glows but the burners never light
Don't Wait for a Total Failure
A failing capacitor, clogged condensate drain, or dirty flame sensor rarely fixes itself and usually gets more expensive to address the longer it runs. Call (805) 209-1970 at the first sign of trouble.
