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 Roswell, NM, the failures cluster at predictable points: a flame sensor coated in oxide that can no longer prove the flame, 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.
Cooling trouble instead? See AC Repair.
Warning Signs for Furnace Repair
The sooner you notice these red flags, the easier and cheaper the fix. Watch for these telltale signs:
- Yellow, wavering burner flames where they should be sharp blue
- Water, rust stains, or black soot around the flue or cabinet
- Burners light, run a few seconds, then shut down repeatedly
- The furnace clicks and glows but the burners never light
- A bang or boom when the burners ignite late
- Grinding or high-pitched squeals from the blower
- A furnace that shuts off every few minutes before the house warms up
- The blower runs constantly but the air never warms
Don't Wait for a Total Failure
What seems like a minor issue today can take out a compressor or heat exchanger tomorrow. Call (575) 203-1118 at the first sign of trouble.
