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 Oak Lawn, IL, 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.
For air conditioning breakdowns, see AC Repair.
Warning Signs for Furnace Repair
Catching these issues early helps you avoid costly problems. Keep an eye out for the following clues:
- Repeated shutdowns just seconds after the burners light
- The igniter glows and clicks, yet no flame ever appears
- Frequent on-off cycling that never reaches the thermostat setting
- The blower runs constantly but the air never warms
- Yellow, wavering burner flames where they should be sharp blue
- Booming or banging at light-off from delayed ignition
- Water, rust stains, or black soot around the flue or cabinet
- Squealing or grinding from the blower compartment
Don't Wait for a Total Failure
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. At the first hint of a problem, call (708) 536-4735 for a fast inspection.
