Start with the thermostat
Make sure the thermostat is set to Heat, the temperature is above the current room temperature, and the fan is set to Auto. If the thermostat display is blank, note that before calling for service.
Check the filter and airflow
A blocked filter or closed supply vents can reduce airflow and cause a furnace to shut down on a safety limit. Check the filter and visible vents. Do not run the furnace without a required filter.
Pay attention to the symptom
A furnace that never starts, starts and stops repeatedly, blows cool air, or makes a new sound gives a technician different clues. Write down what happens and whether the problem affects every room.
Treat gas and electrical warning signs seriously
If you smell gas, leave the building and contact the gas utility or emergency services. If you smell burning, see smoke, or hear a dangerous mechanical sound, turn the system off if it is safe and request professional help. Do not open the furnace cabinet.
Need help with the problem?
HVAC Doctor serves Lexington and the listed Central Kentucky cities. You receive a firm quote before approved repair work begins.
Common questions
Why is my furnace blowing cold air?
The system may be in a startup cycle, have an airflow or ignition problem, or be shutting down on a safety control. A technician needs to identify the cause.
Why does my furnace keep turning off?
Restricted airflow, overheating, ignition trouble, controls, or other equipment issues can cause repeated shutdowns. Avoid repeated resets and arrange a diagnosis.
Does HVAC Doctor repair gas and electric furnaces?
HVAC Doctor provides gas and electric furnace repair in Lexington and its listed Central Kentucky service area.