A furnace blowing cold air in chilly winter is the last thing someone would ever want. Even though your furnace is running well, you would still find cold air blowing out of the vents when the heat is on!
So what is wrong with it?
There can be several reasons why furnace is blowing cold air. While many of these require professional help, some of the causes can be solved by yourself. Knowing the causes of this malfunction will help you to determine you need a technician.
Here are few causes of why furnace in blowing cold air and how you can fix it at home by yourself.
1. Fix the thermostat fan setting
Check if the thermostat setting is changed from “AUTO” to “ON”. When you set the thermostat fan setting to “ON” then your blower fan will run continuously. It runs even when the system is not working to produce heat.
Running continuously 24/7regardless of whether the furnace is heating the air or not, will result in vent blowing cold air sometimes.
If this is the case, then what you have to do is set the thermostat fan’s setting to AUTO from ON. AUTO setting will allow your fan to run only during a heating cycle and not push cold air through your vents in between.
2. Other thermostat issues
Other types of thermostat issues will occur if your thermostat fan is not compatible with your heater. In that case, the only solution is to change your fan and get a new one.
To do that you can consult with an expert nearby.
3. Check Limit Switch
Overheated furnace ends up blowing cold air. But don’t worry there’s a limit switch to maintain safety.
Once the furnace overheats, this limit switch will shut off the burners, but the fan will still run to cool down the furnace. However, you need a permanent solution for that, if this keeps happening.
4. Air filter issues?
One of the main reasons for overheating is a dirty air filter. A dirty air filter restricts the airflow into the furnace making the unit run longer and too harder to provide adequate heat.
Thus changing the dirty air filter is a must. Do keep that in mind that if you don’t replace your dirty air filter soon enough, will damage the heat exchanger resulting in a much costly repair.
How to replace the dirty air filter:
- First, find the filter compartment of your tool and remove its access door.
- Now slide out the old filter
- Third insert the new filter make sure it has the same dimension and you are following the direction marking on the filter frame while attaching the new filter.
- Lastly, replace the old access door with a new one. And you are done!
Once it is done cooling down restart to see if it’s working properly. If not, then get a technician for help.
5. Computerized controls
If you own any newer models you will be used to this feature. Sometimes when the control panel doesn’t work, you will have to shut it off and restart after a waiting for few minutes. As like rebooting your computer whenever it starts glitching.
6. Pilot light goes out?
Do you have an old gas model furnace with a pilot standing? Then you must be familiar with this issue. When you own a gas furnace, combustion of fuel is important for the burner to produce heat.
So check if the pilot light is lit or not when your heater is being a bummer.
How to relight your pilot step by step:
· Turn off the thermostat from HEAT
· Now with the help of the user manual try searching for the pilot assembly at the bottom of the furnace
· After opening the furnace’s cover you will see a knob around the reset switch with three option
· Turn off knob to stop gas coming through pilot and wait few minutes
· Now re-start by tuning it to “pilot”
· After taking all these steps the flame should light
· Now turn the knob to “ON” and your furnace should ignite.
· Now turn the thermostat back to “HEAT” and make sure to set the temperature 5 degrees below room temperature and enjoy the hot air.
In case your pilot still doesn’t light up then you need an expert’s help. DON’T try to fix it by yourself. This can even worsen the problem rather than fix it. The dirty pilot light will also cause hindrance in producing hot air, so cleaning the pilot light is important.
7. Valve issue?
If your pilot light didn’t work after restarting the light assembly then the issue is probably your valve. Faulty gas valves need to be replaced or fixed as soon as possible.
In some cases the gas valves get all dirty with debris stuck on them. For that, you need to clean the gas valve accordingly.
8. Broken Thermocouple
broken thermocouple requires a technician’s help. This feature controls the gas valve and ignition. So it is a bit complex to handle and I would suggest you leave the job to the pros.
9. Clogged oil filter, dirty oil and gas burner
These problems occur when the system isn’t cleaned properly. Dirt and debris affect the ignition causing cold air coming from your heater.
Cleaning these compartments is simple but pretty messy and I wouldn’t suggest you do so either if you don’t know how to.
10. Leaking ducts
If the ductworks have holes in them, then the hot air might escape through those little holes causing your furnace to blow cold air. Get some professional help for that.
Many issues of your furnace blowing cold air can be solved only with a little maintenance and cleaning. Besides, it is even less expensive. Knowing the malfunctions issues will also help you get the right type of professional help.
So, if you still stuck at the answer why furnace is blowing cold air then you can email us just right now. We, furnace cleaning red deer, ab team will solve your problem.