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 moving heat through the ducts. Most of the diagnosis comes down to finding the broken link. In Missoula 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.
Signs You Need Furnace Repair in Missoula
Recognizing the warning signs early can save you time and money. Here are the most common indicators that it's time to call a professional:
- Rust streaks, soot, or water around the cabinet or flue
- Repeated shutdowns just seconds after the burners light
- Air moving through the vents that never gets warm
- Yellow, wavering burner flames where they should be sharp blue
- Short cycling every few minutes without reaching the setpoint
- Clicking and a glowing igniter with no burner flame
- Squeals, scrapes, or grinding noises behind the blower door
- Loud booms at startup caused by delayed ignition
Act Before It Gets Worse
What seems like a minor issue today can take out a compressor or heat exchanger tomorrow. Call (406) 204-2767 at the first sign of trouble.
