Modern furnaces are designed to keep you warm and comfortable, but sometimes they start blowing cold air instead of providing cozy temperatures. If you're experiencing this problem, here are the most common reasons your home's heat is struggling and how to fix them.
Thermostat setting confusion
You may be surprised, but the most common problem may be simpler than you think! Many furnaces have a thermostat that is automatically set to "auto" instead of "heat" all year round. This means that your furnace will continue to blow cool air as long as it senses a drop in temperature.
To force your furnace to start heating your home, make sure your furnace is set to "heat". If you don't see a temperature drop from the sensor, set the temperature a few degrees below your room temperature.
Air Filter Blockage
A clogged air filter is another obvious problem that can also block the flow of warm air into your home. When your air filter is dirty, it reduces the amount of air your heater can circulate. Check your air filter to see if it needs to be replaced. Choose an air filter that matches the size and type of your furnace.
Lack of Gas Supply
Another reason your furnace may blow cold air is a lack of gas supply. A lack of gas can cause a furnace to not ignite properly, resulting in cold airflow and overheating cycles in your furnace. If you think your furnace may be overheating, it's best to contact an experienced HVAC technician to come out and check the gas supply pressure to make sure it's at the proper level.
Now, if these first three problems are relatively easy to identify and fix yourself, you'll want to leave the following problems to your trusted HVAC professional.
Blocked or Dirty Flame Detector
The flame detector is located at the top of the furnace to prevent gas from escaping into the atmosphere. However, if the detector becomes blocked or dirty with dust, dirt, and debris, it will not be able to perform its function properly.
To clean the detector, you must
- turn “off” the gas supply,
- remove the covers from the furnace, and
- clean any dirt from the detector.
Once you have done this, turn the gas back “on” and test the detector to make sure everything is working as it should.
Call an HVAC specialist if you prefer to entrust a flame detector to a licensed professional.
Pilot Light Ignition Malfunction
Furnaces have a pilot light that ignites the gas and keeps it burning. If the pilot light is damaged or needs repair, your furnace will not be able to produce heat.
If you look at the pilot light and it's not lit or flashing, you may need to reset the pilot light. In most cases, the pilot light can be restarted by following these steps:
- turn the pilot light switch to the "off" position,
- wait about 5 minutes and then turn the pilot light back to "on",
- lighting instructions are located on the inside of the furnace door, follow these instructions,
- once the pilot light is lit, check that the flame is steady and does not flicker.
If the pilot light doesn't stay lit, it may need to be replaced. In this case, it's best to contact an HVAC professional for advice and assistance.
Damaged Ductwork
Duct damage is another potential problem. If your ducts are bent, crushed, cracked, or otherwise damaged, warm air will not flow to the proper areas of your home. Repairing this problem may require calling an HVAC specialist to come and check your ducts to make sure there is no damage.
Call HVAC technician to fix the problem
If your furnace is producing cold air, it is time to look for the problems mentioned above. In many cases, a simple repair can get your furnace up and running again, but if you suspect that there are more serious problems with your HVAC system, then it is best to contact an HVAC specialist for professional advice and assistance.
Not only can an experienced HVAC technician help you identify and fix any problems you may have, but they can also perform maintenance on your system to keep it running as efficiently as possible. If you are in Philadelphia and your furnace is blowing unwanted cold air instead of warming your home - leave your request and we will get back to you as soon as possible.
