The part(s) or condition(s) listed below for the symptom Central air conditioner not blowing enough are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
Central Air Conditioner Not Cooling? Central Air Conditioner Troubleshooting
Central Air Conditioner Noisy? Central Air Conditioner Troubleshooting
Central Air Conditioner Fan Motor Not Running? Central Air Conditioner Troubleshooting
Central Air Conditioner Not Running? Central Air Conditioner TroubleshootingSince the furnace's blower motor is the component that circulates the cooled air through the home's venting, a defective blower motor will result in the central air conditioner not blowing enough. You can use a multimeter to test the blower motor for electrical continuity, a continuous electrical path present in the motor, as well as determine if power is reaching the motor. You can also try turning the blower wheel by hand. If the wheel does not turn freely, it's likely the motor bearings have seized and the blower motor will need to be replaced.
Some air registers have adjustable louvers that allow the air flow to be restricted or shut off entirely. This would be used to cut off the air flow to a room that isn't being used, or to restrict air flow to one room so more air will flow to the other rooms. If there is low air flow, check that the louvers are fully open.
Over time the blower wheel and housing can become clogged with dust and debris. This will restrict the air flow, preventing the central air system from blowing enough. You can try cleaning the blower wheel with compressed air or with a soft bristle brush. Use caution when trying to clean the blower wheel as the fins are sharp and can be easily damaged. If the blower is damaged it will need to be replaced.
Over time the blower wheel can become clogged with dust and debris. This will greatly affect the air flow circulating throughout the home. You can try cleaning the blower wheel with compressed air or with a soft bristle brush. Use caution when trying to clean the blower wheel as the fins are sharp and can be easily damaged. If the blower is damaged it will need to be replaced.
A dual run capacitor provides voltage to both the compressor and the fan motor. If the capacitor is defective, the fan motor may not run resulting in the central air system not blowing enough. To determine if the capacitor has failed, test the capacitor with a multimeter. If the capacitor is unable to hold and release a charge or is bulging or leaking, replace it.
The capacitor provides voltage to the fan motor. If the capacitor is defective, the fan motor may not run resulting in the central air system not blowing enough. To determine if the capacitor has failed, test the capacitor with a multimeter. If the capacitor is unable to hold and release a charge or is bulging or leaking, replace it.
If the central air conditioner is low on charge, ice can build up on one section of the evaporator coil, restricting the air flow. Because poor air flow can also cause the coil to freeze up, first confirm the air filter is not clogged and the blower is working properly before checking the sealed system. The sealed system will need to be checked by a licensed technician.
The furnace or air handler air filter should be checked and replaced at least twice a year, more often in dusty/dirty environments. A clogged air filter will greatly reduce the air flow of the furnace or air handler blower.
