If you’ve noticed that your Furnaces fan has been running rather than shutting off as the heating and cooling cycles come on and off, then you have a problem with your HVAC system.
Why is the Furnace Fan Staying On?
There are various reasons why your furnace fan could be staying on, including:
You have the fan switched to “on” instead of “auto.”
If the fan is switched to “on,” it will run continuously until it is shut off. Check to make sure it is set to the “auto” position to ensure it runs only when the furnace runs.
You have thermostat issues
If your furnace fan and cooling system run when they shouldn’t, then you may need to replace the thermostat. If you shut the fan off and it still runs, you will likely need to contact an HVAC repair technician to replace your thermostat.
You have a broken relay switch or a short circuit in the system.
If your fan runs when the furnace is off, then the relay switch may be faulty. This can interrupt the settings entered on the thermostat from being communicated to the fan. Additionally, a short circuit or wiring issues could prevent the on and off commands from reaching the fan.
The AC isn’t sized properly, or the temperatures are too extreme.
If your furnace is too small for your building, it will not run at peak performance and will try to run longer to keep up with your thermostat setting. Additionally, if the outdoor temperatures are really low, then it can cause the furnace to be unable to reach the thermostat setting, causing the furnace and the fan to run longer to reach the desired temperature.
How Can I Troubleshoot this Furnace Issue?
To troubleshoot the issue, start by setting your fan to the “auto” setting. This will ensure that the fan only runs when the furnace is running. You will want to turn the fan switch to “off” and then to “auto.” A thermostat replacement is in order if the fan doesn’t switch off.
If the fan setting is not causing the issue and changing the thermostat doesn’t resolve the issue, then it is possible that your HVAC system is working overtime to keep up with the thermostat setting. You may require regular maintenance to help the system get back to optimal shape.
If our team is unable to get your furnace running at full strength, our HVAC technicians can recommend an HVAC replacement.