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Common Air Conditioner Problems: Mechanical Issues


Our first blog post described common air conditioner problems mostly relating to the comfort level in your home. This second part explains common mechanical issues you may experience with your air conditioner. While there are certainly actions homeowners can take to minimize most of these problems with their unit, such as scheduling semi-annual maintenance tune-ups and changing the air filter regularly, many of these problems may require a professional heating and cooling technician if the issues persist. Read part one of our blog series about common air conditioner problems here.

Unit Shuts On and Off Repeatedly

Most of the time, units that cycle on and off frequently simply need a good cleaning. The condenser can get blocked or the evaporator accumulates dirt and causes the air conditioner to function less efficiently. If you notice the problem continues after getting the condenser, evaporator and fan cleaned, you may have an improperly sized unit or faulty electrical connections. Call a professional technician to determine the root cause and to properly clean, repair, or replace your air conditioner.

A/C Unit Won’t Turn On

An air conditioner that doesn’t turn on may also have electric control failure, but first double check the thermostat. Ensure it is set to cool at the appropriate temperature and has a functioning battery. If the thermostat seems to be operating correctly, check the power and make sure the unit is plugged in and there aren’t any tripped circuit breakers. Once you determine the unit is receiving adequate power and the thermostat does not need to be replaced, the most likely thing preventing the unit from turning on is a worn out compressor or fan controls. Contact a professional to inspect your air conditioner’s electrical controls.

Outside Fan Doesn’t Run

The outside fan is responsible for transferring warm air inside your home to the outside. When you notice the fan isn’t working, call an HVAC professional. The air conditioning compressor could overheat and trip the safety overload or incur internal damage, which would result in a much more costly repair.

Outside Unit Doesn’t Function

When the outside unit doesn’t function the way it should, the cause could be one of two things. Either the unit isn’t receiving power or the thermostat is faulty. Remember to check the thermostat settings and the power supply before contacting your heating and cooling contractor.

Coils Are Frozen

If you notice the coils are frozen on your air conditioner, the most likely issue is airflow. Dirty air filters or blocked return ducts can cause the coils to freeze due to restricted airflow. Replace the filter and clear returns of any obstructions. A frozen coil could also be a sign of low refrigerant. Call an HVAC expert to add refrigerant or inspect the unit for any other problems.

Remember to always give Lenz Heating & Cooling a call if you ever have any questions or concerns about the air conditioner in your home. We never have trip charges, overtime fees, or diagnostic fees.