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 Tyler 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.
For air conditioning breakdowns, see AC Repair.
Warning Signs for Furnace Repair
The sooner you notice these red flags, the easier and cheaper the fix. Keep an eye out for the following clues:
- Booming or banging at light-off from delayed ignition
- A flame that burns soft and yellow rather than steady blue
- Short cycling every few minutes without reaching the setpoint
- Squeals, scrapes, or grinding noises behind the blower door
- Soot, rust, or moisture near the furnace cabinet or vent pipe
- Flames that start, last a few seconds, and go out again and again
- The blower runs constantly but the air never warms
- The furnace clicks and glows but the burners never light
Act Before It Gets Worse
Most HVAC failures start small, a weak capacitor, a squealing blower, a system that runs a little longer each week. At the first hint of a problem, call (903) 200-8228 for a fast inspection.
