Furnace Flame Sensor Cleaning & Replacement

Professional Furnace Flame Sensor Cleaning & Replacement in Asheville & Western NC

The Tiny Part That Causes Big Headaches

The flame sensor is a small metal rod positioned in the burner flame. Its job is simple but critical: detect whether the gas burners have actually ignited. If the sensor doesn't detect flame within a few seconds of gas flow, the control board shuts down the gas valve as a safety measure. When the sensor gets coated with oxidation or combustion residue, it can't sense the flame properly — causing your furnace to light, run for a few seconds, then shut off and try again. This frustrating short-cycling is one of the most common heating complaints we hear from WNC homeowners.

Cleaning vs. Replacement

In many cases, a simple cleaning with fine abrasive restores the flame sensor to full function — a repair that takes about 15 minutes. If the sensor is cracked, warped, or cleaning doesn't resolve the issue, replacement is straightforward and inexpensive. Either way, this is one of the quickest furnace repairs in our playbook.

Part of a Thorough Diagnosis

Flame sensor issues can mimic other problems like a failing gas valve, a cracked ignitor, or a bad control board. Our technicians don't just clean the sensor and hope — we verify the sensor's microamp reading, test the gas valve, and confirm proper operation before considering the repair complete.