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 Aurora, CO, the usual failure points are a flame sensor fouled with oxide, 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
Recognizing the warning signs early can save you time and money. These are the signals our technicians see most often:
- Air moving through the vents that never gets warm
- Squealing or grinding from the blower compartment
- Loud booms at startup caused by delayed ignition
- The igniter glows and clicks, yet no flame ever appears
- Repeated shutdowns just seconds after the burners light
- A furnace that shuts off every few minutes before the house warms up
- Soot, rust, or moisture near the furnace cabinet or vent pipe
- Yellow, wavering burner flames where they should be sharp blue
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 (970) 602-4904 at the first sign of trouble.
