From the hallway, a furnace that will not heat looks the same no matter what broke. Inside the cabinet, though, everything happens in a strict order: inducer on, pressure switch closed, igniter glowing, gas valve open, burners lit, flame proven, and finally the blower sending heat through the house. Most of the diagnosis comes down to finding the broken link. In Brentwood homes, it tends to be the same handful of culprits: a flame sensor coated in oxide, a hot surface igniter cracked by thermal cycling, a pressure switch held open by a tired inducer or a plugged condensate trap, or a control board with a burned relay.
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. Keep an eye out for the following clues:
- Soot, rust, or moisture near the furnace cabinet or vent pipe
- A pilot or burner flame that is lazy yellow instead of crisp blue
- A furnace that shuts off every few minutes before the house warms up
- A fan that keeps running while the registers blow cool air
- The igniter glows and clicks, yet no flame ever appears
- Burners light, run a few seconds, then shut down repeatedly
- Squealing or grinding from the blower compartment
- A bang or boom when the burners ignite late
Act Before It Gets Worse
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 (925) 205-6539 for a fast inspection.
