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 New Bedford, MA, 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. Each one 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
Catching these issues early helps you avoid costly problems. Here are the most common indicators that it's time to call a professional:
- Soot, rust, or moisture near the furnace cabinet or vent pipe
- Repeated shutdowns just seconds after the burners light
- Short cycling every few minutes without reaching the setpoint
- Clicking and a glowing igniter with no burner flame
- A bang or boom when the burners ignite late
- Squeals, scrapes, or grinding noises behind the blower door
- A fan that keeps running while the registers blow cool air
- Yellow, wavering burner flames where they should be sharp blue
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 (774) 533-7670 for a fast inspection.
