A modern furnace runs a strict startup sequence, and knowing where the sequence breaks is most of the diagnosis. The thermostat calls, the inducer motor spins up to prove draft through a pressure switch, the hot surface igniter glows, the gas valve opens, the burners light, the flame sensor confirms fire, and only then does the blower deliver heat to the house. In Montgomery, AL, the failures cluster at predictable points: an oxide-coated flame sensor, a hot surface igniter cracked from years of thermal cycling, a pressure switch that will not close because the inducer is weak or the condensate trap on a high-efficiency model has clogged, or a control board with a burned relay. Each one stops the sequence cold, and each one mimics the others from the hallway.
For air conditioning breakdowns, see AC Repair.
Warning Signs for Furnace Repair
Spotting the early warning signs lets you act before the problem gets expensive. Watch for these telltale signs:
- Water, rust stains, or black soot around the flue or cabinet
- Loud booms at startup caused by delayed ignition
- The furnace clicks and glows but the burners never light
- A pilot or burner flame that is lazy yellow instead of crisp blue
- Flames that start, last a few seconds, and go out again and again
- A furnace that shuts off every few minutes before the house warms up
- The blower runs constantly but the air never warms
- Squeals, scrapes, or grinding noises behind the blower door
Don't Wait for a Total Failure
What seems like a minor issue today can take out a compressor or heat exchanger tomorrow. Don't wait, call (251) 485-1530 and we'll take a look right away.
