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.
A thermal expansion valve, commonly referred to as a TXV, regulates the amount of refrigerant in the evaporator coil to help maintain an optimal working temperature.
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 evaporator in a central air conditioning system is located either in the furnace or air handler. Refrigerant in the system is pumped through the evaporator and absorbs heat from the circulated air passing through it from the blower. Because of the damp environment, corrosion can start to deteriorate the welds on the aluminum or copper coils. When this happens, the refrigerant can leak out of the system and the evaporator coil will need to be replaced.
Located in a housing, the blower wheel may be directly attached to a motor or driven by a belt which spins the blower wheel to create air flow. If the blower fins are clogged or damaged, the blower wheel may not move enough air or may vibrate and cause unwanted noise. A damaged blower wheel will need to be replaced.
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.
A filter drier helps to keep the refrigerant used in the condensing unit's sealed system clean and it also helps to remove moisture from the system. Although not usually the cause of a sealed system failure, the filter drier should be replaced any time the sealed system is compromised, such as when a compressor or evaporator is replaced, or when a refrigerant leak needs to be repaired.
