If your air handler is running but not blowing air, there are two likely scenarios: either a broken AC blower belt or an issue with the motor itself. If the air handler is humming or buzzing but not making the mechanical sounds of a motor running, you're most likely talking about an issue with the motor itself.
When your furnace runs but fails to blow air, several issues could be at play: Blower Motor Problems: If the motor is malfunctioning or not receiving power, it can't push air through your ducts. This could be due to electrical issues, a faulty motor, or problems with the motor's capacitor.
If the airflow is stopping and not switching to another vent, but the blower is still heard, then it is likely that there is an issue with the fan blades separating from the motor. If this is the case, then the blower motor assembly will need to be replaced. Does this make sense?
Coil is frozen. If the fan is spinning, but no air is moving, this is likely the culprit. If your coil is frozen, you probably have a refrigerant leak.
If the fan motor is still working, but just not operating as it should, you may need to replace the blower fan resistor assembly. The blower fan resistor is a simple electronic circuit that changes the resistance of the current sent to the blower motor, and enables multiple fan speeds.
An issue with your blower may also cause a lack of airflow. It may have blown a fuse, have a defective connection, or simply suffer from normal wear and tear. Besides having weak or no airflow, another common symptom that may indicate a blower malfunction is hearing strange noises when turning your air conditioning on.
The most common problems that cause a lack of airflow include frozen coils, broken fan and restricted airflow due to dirty air filters or vent obstruction. However, there are many other issues that can lead to minimal airflow, so it may be necessary to ask the professionals.
Check Your Air FilterOn the opposite side, if your AC and fan are both running and you still are not getting airflow through your vents, you will want to check for a dirty air filter. The air filter collects dust and debris and can block airflow through your system if not changed routinely.
Power down your AC: Turn off your AC unit and unplug it from the power source. This will ensure that you stay safe while working on the unit. Locate the reset button: Most air conditioning units have a reset button located near the outside unit. It is usually a small button located inside a small hole.
If the filter is clogged, replace or clean it immediately, then rerun the furnace. If this does not correct the airflow issue, make the call for help, as it's likely an issue with an internal component, such as the blower or control board, that will require an experienced technician to diagnose and repair.
Most blower motors are controlled by a red or black switch on the side of the unit. Hold the button down for a few seconds (the manual will tell you precisely how long), then release. Replace the Panel and Restore Power.
If your outside AC unit is running but no cold air is blowing inside, the likely causes include low refrigerant, a dirty air filter, or a faulty compressor. These problems reduce cooling efficiency.
If your air handler is running but not blowing air, there are two likely scenarios: either a broken AC blower belt or an issue with the motor itself. If the air handler is humming or buzzing but not making the mechanical sounds of a motor running, you're most likely talking about an issue with the motor itself.
Fan Placement and Direction
For optimal fan efficiency, placement is key. Positioning a fan near windows can enhance natural airflow, either drawing in fresh air or pushing out warm air. Additionally, directing the fan towards where you are, ensures you feel its cooling effect more directly.
When airflow is low, the impeller is likely installed backwards or it's running backwards. Other probable causes are improper blade angle setting, missing cut-off, too slow fan speed, dirty or clogged impeller or inlet, improper running clearance, or improperly set inlet vane or damper.
You can generally identify a blocked air duct by a distinct drop in heating and cooling efficiency, increased energy costs, and occasionally a musty, dusty smell throughout the home. The blockage usually comes over time, by a buildup of dust and debris that just accumulates until it begins choking the system.
The short answer: Definitely not. (Unless you have manually engaged your outside fan to run constantly, but it shouldn't be running for hours on it's own.) If your HVAC is functioning correctly, it should keep your house cool by cycling on for 15-20 minutes at a time—with distinct pauses in between each cycle.
An outside AC fan not spinning could be caused by power supply issues, a faulty capacitor, a burnt out motor, contactor issues, wiring problems, debris or obstruction, a faulty thermostat or control board, or frozen evaporator coils. Contact your local Carrier dealer to help troubleshoot the issue further.
On some platforms, a faulty blower motor relay will cause the blower not to work at all, which means there will be no airflow from the A/C. On others, the blower won't work on “high blow” but all the other speeds will work. The blower motor relay fails because it regularly deals with high current loads.
Replacing a furnace blower motor costs $560, on average. Depending on the size and type of motor, most people pay $300 to $900. The average blower motor replacement cost is $560, but the final price depends on labor fees, as well as the cost of the parts.