Every time your thermostat calls for heat, the furnace runs 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 San Diego, 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.
When to Call for Furnace Repair in San Diego
Recognizing the warning signs early can save you time and money. Keep an eye out for the following clues:
- A fan that keeps running while the registers blow cool air
- Frequent on-off cycling that never reaches the thermostat setting
- A bang or boom when the burners ignite late
- Yellow, wavering burner flames where they should be sharp blue
- The furnace clicks and glows but the burners never light
- Squeals, scrapes, or grinding noises behind the blower door
- Soot, rust, or moisture near the furnace cabinet or vent pipe
- Repeated shutdowns just seconds after the burners light
Early Action Saves Money
What seems like a minor issue today can take out a compressor or heat exchanger tomorrow. If you notice any of these signs, call (619) 313-5467 for a prompt inspection.
