More often than not, this occurs because the filter is dirty; this blocks airflow, which means the hot air circulates through your furnace, overheating it.
Typically, these are air flow-related issues, like the fan or filter is broken. Then, the heat generated by the furnace can't leave, causing the overheating. However, there may be other culprits too. You'll need a professional to help you figure out what is going on.
In most cases, a malfunctioning thermostat is the cause of your home's overheating. When the temperature sensor inside your thermostat detects the wrong heat levels, it will tell your heater to keep running even if your home is already comfortably warm.
A common cause of a furnace blowing too hard is a faulty thermostat. Your thermostat communicates with the heating system and tells it when to shut off. Once the temperature in the home dips below the temperature you set, it signals it to kick back on.
There's a problem with your filter.
If the airflow to your heater is restricted, it can trigger your furnace burner to turn off while the blower keeps running. This will make the air just warm (or chilly).
This problem often points to inadequate circulation of warm air. It could be due to blocked vents, a failing HVAC fan, or issues with the furnace itself. Ensure that furniture or drapes are not blocking your vents. Also, check if your furnace's filter is clean, as a dirty filter can restrict airflow.
Common Causes of an Air Conditioner Blowing Warm or Hot Air
These can be due to clogging issues, electrical problems, low refrigerant, evaporator coil malfunctions, or compressor problems. If you've ever had the ac system in your car stop functioning, it's often due to a refrigerant leak or dirty coil.
Excess airflow in winter, however, provides too much heat, and a room may be chronically uncomfortable. Airflow issues may be caused by internal duct dampers that are not adjusted properly, too many closed or obstructed supply vents in the house, or a furnace blower that is oversized for the system.
It's most likely an incorrect thermostat setting if you find your furnace blowing warm air, not hot. The fan is set to “on” instead of “auto.” Furnaces only pump hot air until the thermostat setting is reached, so if your fan is always on, it will blow both hot air when the furnace is heating and cold when it's not.
This problem can be caused by a variety of factors, such as insufficient insulation, a damaged AC system, or ventilation issues. Fortunately, there are ways to address these issues that can not only boost your comfort but also lower your energy bills.
If you have a dirty or clogged furnace filter, the cool air from inside your home will struggle to travel through it and into the furnace. This means you have insufficient air to heat and redistribute. The result is your heater blowing cold air.
The heating system should accordingly match the thermostat. To do this, many things like size and type of the furnace, its capacity, and capability have to be considered. If the thermostat and heating appliance do not match, it can cause the heating system to malfunction.
A furnace cycling on and off repeatedly can be caused by various reasons, from dirty filters and obstructions in ducts and registers to incorrect thermostat settings and faulty limit switches. By following the steps above, you can help prevent your furnace from cycling too frequently and save energy costs.
Restricted Airflow
The internal components of your furnace can get too hot when there isn't good airflow. This usually happens when you forget to change your air filter regularly. The air filter traps dust and other contaminants that can clog your furnace's ventilation system.
Hot air leaving the furnace burner is generally between 140 and 170 degrees Fahrenheit. By the time the airflow passes through the ductwork and enters a room at the supply vent, the temperature has typically dropped to about 120 to 140 degrees.
When your heater runs, your vents may get a bit warm from the air. But if you touch the vents in your home and they're hot, it's a sign of improper venting.
A gas furnace should have a vibrant or bright blue flame. When you see a weak and wavy or flickering flame, this indicates gas is not being completely burned. Pilot light color changes are another indicator that carbon monoxide is not venting away from the system safely.
Air entering the water heating system through leaks in the pipes can be the most troublesome cause of air in your radiators. These leaks can be caused by corrosion, damage to pipe joints, or a faulty radiator valve.
Understanding Excess Air in Furnaces and the Potential Problems It Causes. Too much excess air can reduce your furnace's energy efficiency and introduce more carbon monoxide into the air. Why? When there's too much excess air in the system, it dilutes the water and carbon dioxide during the combustion process.
Start by making sure that your thermostat is calibrated correctly. A miscalibrated thermostat can lead to inaccurate temperature readings. This will cause it to overshoot the desired temperature. Look at your thermostat's manual or contact the manufacturer to recalibrate it.
Ductwork Issues
If your ductwork is leaking or damaged, it can draw hot air back into the supply ducts or let all of the cooled air escape. This can result in the AC system blowing hot air through the house. Ductwork leaks can also reduce the volume of air flowing through the system.
One of the solutions to HVAC blowing hot air would be to turn off your unit, clean the condensation drain, and allow the coils to defrost before turning the system back on.