When your thermostat is set to AUTO, your furnace fan should blow only when your furnace is in the middle of a heating cycle. But if your fan runs constantly, regardless of whether your furnace is heating, that’s not normal. Your fan limit switch is on “manual override” There’s a shorted thermostat wire.
Similarly, you may ask, should fan on furnace be on auto or on?
Setting the fan on “auto” The fan only runs when the furnace tells it to. On cooling, the fan will run only when the air conditioner is running. Pros. The “auto” setting means less energy usage, because it keeps the fan running the least amount of time at the slowest speed needed for heating and cooling.
Secondly, what causes a furnace fan to keep running? Dirty furnace filters are one of the biggest causes for a furnace to continuously run or “short cycle”. The dirty filter restricts airflow across the heat exchanger which causes it to get too hot! The furnace goes into cool down mode and will run the fan continuously and will cause your furnace to blow cold air.
In respect to this, why wont the fan shut off on my furnace?
First, try this: Make sure your thermostat fan setting is on AUTO not ON. If your furnace fan won’t turn off, you most likely have one of these 3 problems: Your furnace fan limit switch is set to “manual override” The fan limit switch is faulty and needs to be replaced.
Should you run your furnace fan 24 7?
When you set your fan to “ON,” you’re telling it to keep running 24 hours a day, 7 days a week, regardless of the heating or cooling setting. Leaving the fan on 24/7 ensures cleaner air, as the air is pulled through the filtration or UV light system. This can be better for people with allergies.
12 Related Question Answers Found
Is it better to run the furnace fan all the time?
By running the furnace fan all the time, you are also running air through your furnace filter constantly, so if you have an efficient filter and a UV light, you are constantly filtering and cleaning the air. This results in healthier indoor air quality for your family and less dust on your furniture.
Is it OK to run furnace fan constantly?
Drawbacks to Running Your Furnace Fan Continuously Furnaces with high-efficiency motors, however, should not increase your electric bill. In fact, running your furnace fan constantly may even save you money since having more even temperatures in your home may result in the heat or air conditioner running less.
How often should furnace fan run?
Mild Temperatures Can Be Optimal For Fan Usage The circulate feature on some thermostats will automatically run the fan for around 20 minutes out of every hour. This helps circulate the air and maintain a more balanced temperature without having to run the fan continuously.
How much does it cost to run your furnace fan all the time?
Therefore, the fan uses about 360 kWh per month in the ON mode. The average kWh in the US costs about $0.12 so it costs about $43 per month, or about $520 per year, to run a fan continuously. At this point, it should be pretty obvious that AUTO costs less than ON but let’s math it out to its logical conclusion.
Should you leave your thermostat fan switch set to on or auto?
“Auto” means that the fan automatically works ONLY when the air is being heated or cooled. So once your home reaches the temperature set on the thermostat, the fan stops. “On” means the fan is on 24/7, even when the air isn’t being heated or cooled.
Why does the thermostat not shut off?
Faulty thermostat. If your thermostat is not working correctly, the unit doesn’t know to turn off even when the temperature is reached. If enough cool air escapes, the temperature in your space never reaches the set point and the system will keep running. Dirty or blocked condenser.
How do I adjust the fan limit on my furnace?
How to Set a Fan Limit Control Switch Open up the access panel on the furnace. Look for the fan limit control switch encased in a small rectangular box. Slide the cover off the control switch or lift it up. Set the markers to the appropriate settings for your furnace. Pull out the white switch to reset the limit control to automatic.
How do you reset a furnace fan?
How to Find My Furnace Motor Reset Button Turn off the power to the furnace at the circuit breaker. The circuit breaker is clearly marked. Lift up the blower compartment cover to access the blower wheel and blower motor. Look for a small red or yellow button on the side of the blower motor. Press the reset button down if it has popped up.
Why does my furnace run when the thermostat is off?
If your furnace keeps blowing hot air and won’t stop, the furnace burners aren’t turning off. Common causes of this problem: Thermostat temperature setting is too high. The furnace will run constantly to keep up on a cold night.
Is it OK to leave the AC fan on?
So, putting the fan in the “on” position compounds the error of having an oversized cooling system. Your house will cool down quickly without dehumidifying well. Running the fan continuously makes the humidity worse and your home less comfortable.
How much electricity does a furnace fan use?
Variable Speed Furnace Fans A standard fan motor will typically use about 400 watts per hour while a variable-speed model will only use 75 watts per hour. This is the most direct way that the variable-speed units save electricity, but there are other means by which they affect energy usage as well.
Does HVAC fan pull air from outside?
In short, no. Though in split system air conditioners design, commonly heat pumps, part of your system is located outside your home, it does not take in outside air. Its main operational purpose of cooling the air in your home is not achieved by moving cool air inside, but by moving unwanted heat out.