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 start pushing warm air into the house. Finding the step that fails is most of the job. Around Portsmouth, NH, 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.
For air conditioning breakdowns, 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:
- A flame that burns soft and yellow rather than steady blue
- Grinding or high-pitched squeals from the blower
- A furnace that shuts off every few minutes before the house warms up
- The igniter glows and clicks, yet no flame ever appears
- A fan that keeps running while the registers blow cool air
- Booming or banging at light-off from delayed ignition
- Rust streaks, soot, or water around the cabinet or flue
- Burners light, run a few seconds, then shut down repeatedly
Act Before It Gets Worse
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. Call (857) 767-3372 at the first sign of trouble.
