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Is your furnace not blowing air through vents? When you have no air coming out of vents in house, this could be due to a few reasons which include thermostat settings, dead blower capacitor, issue with the blower motor, tripped circuit breakers, blocked vents and registers, and a malfunctioning circuit control board.
In this article, we have put together steps to troubleshoot these issues, so read on to learn more.
Troubleshooting a Furnace Not Blowing Air Through Vents
There are quite a few things that can prevent air from coming out vents in your house. But when you notice that your furnace is not blowing out air through vents, these are the steps that you need take to troubleshoot this issue.
1. Check Your thermostat
This is the first thing that you always need check when your furnace has issues. Make sure you check that:
- The settings on your thermostat are in order. If you are one of the homeowners using the programmable thermostats, look at the settings that are there. And check if your thermostat is correctly programmed. Because you can set different temperatures at different times of the day, ensure that there is no mistake when programming your thermostat. If everything looks cool with your thermostat, move on to the next troubleshooting step.
- Your thermostat clock is correct. It’s annoyingly easy to program a thermostat having a wrong time. So, what can happen is that your thermostat thinks you are not home, when in fact, you are actually having your dinner. Double check the time on your thermostat and correct it accordingly!
2. Make Sure Your Furnace Is Turned On
After you have checked with your thermostat, but you have no air coming out of vents, then head over to check if your furnace is turned on. You can check it by:
- Going to the furnace power switch and check if it’s on the ‘on’ position. If it’s off turn it on and adjust the temperature on your thermostat to see if air will come through.
- Problem still there? Check the circuit breaker. If the breaker for your heating system is tripped, flip it back.
3. Dead Blower Capacitor
Now that you have checked your thermostat and the power supply to your furnace and they all look good, there is a chance that the problem lies with the furnace blower. Some issues that arise with the furnace blower include:
- Dead blower capacitor: The blower capacitor stores and gives energy to the blower for it to start working work. If the blower capacitor is not working or malfunctioning, it will not start the motor. And if that happens, it could be the reason you have no air coming out of heating vents in house.
- Broken belt. Another issue that can arise with your blower motor include a broken belt that drives the blower fan.
The furnace blower draws air into the furnace and forces it into the ductwork of your home. If it has any issues that stop is from blowing air, then you won’t have any air coming out of vents in your home.
In some cases, all you need to do, to get your furnace blower to work is simply resetting it. You can reset your furnace blower by first opening the door to the blower compartment. In most furnaces, the reset button is found close to the blower motor.
A malfunctioning furnace blower can also cause other issues such as overheating and short cycling.
4. Blocked Registers or Vents Can Cause No Air Coming Out of Vents in One Room
Are you experiencing no air coming out of vents in one room only? Then your vents or registers could be blocked or accidently closed.
If registers are blocked, air won’t circulate freely into your room. But here is how you can easily unblock registers or vents:
- Move away objects like chairs, rags, or dressing tables from anywhere near the vents.
- Look around your room for any closed registers. If you find any try opening them and see if air will start flowing in
Also read: Furnace Will Not Turn on With Thermostat
5. Leaky Ductwork Could Be the Reason for No Air Coming Out of Heating Vents in House
Did you know that, overtime your ductwork could have problems or even have leaks? In some cases, they can develop disconnections especially if no proper job was done on them during the installation.
Because ducts are installed outside areas with controlled temperatures like in the attic. The high temperature changes could make them expand and contract between seasons eventually causing issues.
Other times, rodents could be the culprits for no air coming out of heating vents in house. If these intruders find their way into your attic, they will cause some damage to the air ducts.
If you have leaky air ducts, air will escape through leaks before making it into your living spaces.
Faulty Circuit Control board
In Some cases, the problem could be a faulty circuit control board. The circuit control board is like the head of the furnace. It coordinates all other components of your furnace
When the circuit control board receives heating cycle instructions from the thermostats, it relays information to other parts of the furnace including the blower motor to start pumping air. But if the circuit control board is compromised of malfunctioning, it might miss sending instructions to the blower motor.
This could be the reason for no air coming out of heating vents in house
How do you reset a furnace blower motor?
You can reset your furnace blower motor by following these steps.
Turn off the furnace by its power switch
Go to the blower compartment and open the door.
Be careful as the motor could be hot
Find the reset button, it’s usually found on the side of the motor
Push in the rest button if it has popped
How long do furnaces usually last?
On average, a furnace can have a lifespan of anywhere from 15 to 20 years. But with regular maintenance, your furnace could even stay much longer.
We hope that this guide will help you greatly especially if you are dealing with furnace not blowing air through vents. If you are unsure about handling anything yourself, it is always smart to call in professional HVAC service.
HVAC tech with over 30 years of experience. Retired and doing repair work on the side around Madison County, AL.