Several factors could contribute to an air conditioner evaporator coil not working properly.

Reasons Of Evaporator coil not working

Dirty or Clogged Coil:

Issue: Over time, the evaporator coil can accumulate dirt, dust, and debris, reducing its ability to absorb heat.

Solution: Regularly clean the evaporator coil. Use a soft brush or a vacuum cleaner with a brush attachment to remove debris. Be cautious not to damage the delicate fins on the coil.

Frozen Evaporator Coil:

Issue: If the refrigerant levels are too low or if there’s restricted airflow, the evaporator coil may freeze, hindering its ability to function.

Solution: Check and replace a dirty air filter. Ensure proper airflow by keeping vents unobstructed. If the problem persists, consult a professional to check for refrigerant leaks or low refrigerant levels.

Faulty Expansion Valve:

Issue: The expansion valve regulates the flow of refrigerant into the evaporator coil. If it malfunctions, it can lead to issues with the coil.

Solution: A faulty expansion valve should be replaced by a qualified HVAC technician.

Refrigerant Issues:

Issue: Incorrect refrigerant levels can impact the coil’s ability to absorb heat.

Solution: Consult a professional HVAC technician to check refrigerant levels and recharge the system if necessary.

Air Filter Issues:

Issue: A clogged or dirty air filter can restrict airflow over the evaporator coil.

Solution: Replace or clean the air filter regularly, following the manufacturer’s recommendations.

Thermostat Problems:

Issue: Incorrect thermostat settings or a malfunctioning thermostat can impact the operation of the evaporator coil.

Solution: Check and adjust the thermostat settings. If the thermostat is faulty, consider replacing it.

Blocked Condensate Drain:

Issue: A blocked condensate drain can lead to water accumulating around the coil, affecting its performance.

Solution: Clear the condensate drain of any obstructions. This may involve using a wet/dry vacuum or a mixture of water and vinegar to dissolve debris.

Electrical Issues:

Issue: Electrical problems, such as a malfunctioning capacitor or relay, can impact the functioning of the evaporator coil.

Solution: If you suspect an electrical issue, it’s essential to have a professional HVAC technician inspect and repair the system.


If you’re unable to identify or resolve the issue on your own, it’s recommended to seek the assistance of a qualified HVAC technician. They have the expertise to diagnose and fix complex problems related to the evaporator coil and the overall air conditioning system.