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 Denver, CO, 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. Any one of them halts the startup, and from the hallway they all look alike.
For air conditioning breakdowns, see AC Repair.
When to Call for Furnace Repair in Denver
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:
- Frequent on-off cycling that never reaches the thermostat setting
- Loud booms at startup caused by delayed ignition
- Grinding or high-pitched squeals from the blower
- A pilot or burner flame that is lazy yellow instead of crisp blue
- The blower runs constantly but the air never warms
- Flames that start, last a few seconds, and go out again and again
- Soot, rust, or moisture near the furnace cabinet or vent pipe
- Clicking and a glowing igniter with no burner flame
Early Action Saves Money
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. If you notice any of these signs, call (970) 602-4899 for a prompt inspection.
