Leave the area and follow emergency guidance from your gas utility or emergency services. Do not keep troubleshooting, operate switches, or try to locate a gas leak yourself.
Start with these safe checks
Confirm HEAT is selected and the target temperature is above the room temperature.
A badly clogged filter can restrict airflow. Replace it only if you normally do this safely.
Make sure supply vents are open and unobstructed. Notice whether there is no airflow or simply cool airflow.
Gas odor, burning smells, smoke, repeated shutdowns or unusual electrical symptoms need professional attention.
What the symptom can tell you
No air at allThermostat, power, blower or control problems may be involved.
Air blows but stays coolThe heating stage may not be operating correctly even though the fan runs.
Starts, then shuts off repeatedlySeveral airflow, safety-control or equipment faults can cause short cycling.
Ask these questions.
- Is there a diagnostic or service-call fee?
- Will you explain the fault before beginning repair?
- What is the total quoted repair price?
- What warranty covers parts and labor?