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 start pushing warm air into the house. Finding the step that fails is most of the job. Around Cypress, 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. Keep an eye out for the following clues:
- Loud booms at startup caused by delayed ignition
- Air moving through the vents that never gets warm
- Squealing or grinding from the blower compartment
- Rust streaks, soot, or water around the cabinet or flue
- The igniter glows and clicks, yet no flame ever appears
- Flames that start, last a few seconds, and go out again and again
- A pilot or burner flame that is lazy yellow instead of crisp blue
- Short cycling every few minutes without reaching the setpoint
Act Before It Gets Worse
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. If you notice any of these signs, call (714) 650-8915 for a prompt inspection.
