For every problem, there’s a solution. Keep telling yourself this if you find yourself asking, Why won’t my furnace start? Then call a trusted HVAC professional for an in-depth inspection.
Before the HVAC appointment, tackle these troubleshooting steps if your furnace won’t start:
- Check that your furnace is on and set at “heat.” Then check the furnace temperature and room temperature. The latter may be higher than the former, which would explain why your furnace won’t turn on. Set the furnace temperature at least 5 degrees higher than the room temperature to kick-start your furnace.
- While you’re at the thermostat, pop it open and remove any dust by giving the components a good blast of air. Dust buildup could be blocking the signal to the furnace.
- Ensure that the thermostat is displaying the correct day and time. Thermostats can be so sensitive that if they’re not programmed correctly, they won’t work correctly either. Replace the battery in the thermostat. Then ensure that the thermostat is snugly affixed to the wall, with no exposed wires.
- Turn the fan switch to “on” to see if the furnace is receiving power. If it isn’t, check the furnace’s circuit breaker or fuse. Turn off the breaker, wait a few minutes and then turn it back on. If your furnace still won’t turn on, replace the breaker.
- Ensure that the switch on the switch supervisory unit, usually mounted on a wall near the furnace, is “on.”
- Ensure that the gas valve, located on the side of your furnace, is open.
- Check the pilot light. If it isn’t on, relight it.
- Look for flakes of rust near your furnace, which can fall on the burners and interfere with the gas flow. This condition requires a fix by an experienced HVAC contractor.
- Check the condition of the air filter. If it’s clogged with dust, replace it. A dirty filter can shut down a furnace.
If the problem persists – and you’re still asking, Why won’t my furnace start? – it’s time to call the furnace experts at Gulf Coast Air Systems. We proudly service homeowners in Valrico, Riverview and surrounding areas.