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 Kalamazoo, MI, 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.
For air conditioning breakdowns, see AC Repair.
Warning Signs for Furnace Repair
The sooner you notice these red flags, the easier and cheaper the fix. Keep an eye out for the following clues:
- Frequent on-off cycling that never reaches the thermostat setting
- Clicking and a glowing igniter with no burner flame
- Water, rust stains, or black soot around the flue or cabinet
- Yellow, wavering burner flames where they should be sharp blue
- A bang or boom when the burners ignite late
- Squealing or grinding from the blower compartment
- Flames that start, last a few seconds, and go out again and again
- Air moving through the vents that never gets warm
Early Action Saves Money
A failing capacitor, clogged condensate drain, or dirty flame sensor rarely fixes itself and usually gets more expensive to address the longer it runs. At the first hint of a problem, call (269) 201-8609 for a fast inspection.
