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. Diagnosis is mostly a matter of finding where that chain breaks. In Leominster 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.
Warning Signs for Furnace Repair
The sooner you notice these red flags, the easier and cheaper the fix. These are the signals our technicians see most often:
- A pilot or burner flame that is lazy yellow instead of crisp blue
- Flames that start, last a few seconds, and go out again and again
- Soot, rust, or moisture near the furnace cabinet or vent pipe
- Loud booms at startup caused by delayed ignition
- Frequent on-off cycling that never reaches the thermostat setting
- The blower runs constantly but the air never warms
- Clicking and a glowing igniter with no burner flame
- Squealing or grinding from the blower compartment
Don't Wait for a Total Failure
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 (351) 345-9278 for a prompt inspection.
