12 Common Problems with PTAC Units & How to Fix Them

While PTAC units are the best option for energy-efficient, cost-effective climate control, they are not exempted from problems you usually experience from other types of ACs. There are easy solutions to the problems in most cases, but you have to know what to look for. Here are 12 common problems with PTAC units.

1) PTAC Unit Not Blowing Hot or Cold Air

2) Unit not turning on

3) Unit running continuously

4) Unit making a humming or buzzing noise

5) Inadequate pressure flowing in or out of the unit

6) AC unit leaking water inside your room

7) Push buttons not working correctly

8) Tripping of circuit breaker

9) Humidity and moisture problems

10) Black mold coming from air vents

11) Ice formation on the unit

12) Temperature mismatch

A Humming or Buzzing Noise

The buzzing or humming noise could be due to damaged isolation feet, a malfunctioning compressor, or loose parts in your packaged terminal air conditioner. Either way, you probably may need to get a professional to get that fixed.

PTAC Unit Not Blowing Hot/ Cold Air

Having to struggle with an air conditioning unit blowing cold air when you need to blow warm air and vice versa is pretty annoying. This problem could be due to the thermostat or the refrigerant levels. If your PTAC unit has issues blowing hot air, you can look at your thermostat for proper operation. Shorted wires impact the performance of the PTAC unit, too, which can lead to it not properly functioning. Lastly, there may be low refrigerant levels for problems associated with the cooling issues. If that is the case, then make sure to remove any blockages in the coolant lines. Also, be sure to clean your PTAC filters and coils.

Unit Not Turning On

Aside from making sure your air conditioning is plugged in, you probably would want to look at the power cords for shorts. You also want to make sure that the connection is not interrupted by lousy wiring or breakage. You can try testing the voltage of the power cord to ensure the voltage is enough to support the PTAC system. Make sure to check for any blown fuses.

System Operating Pressures

Inadequate pressure flowing in or out of the PTAC unit can cause operational issues. You may notice that your packaged terminal air conditioner suction or discharge pressures are lower than usual. This is usually caused by insufficient refrigerant or the blocked coolant lines. Or the lines simply need to be replaced. When the operating pressures of the PTAC units are high, this may be due to bad wiring with the fan motor or a bad compressor. Make sure to check the blower fans’ compressor and ensure the coils and the air filter are clean.

Humidity And Moisture Problems

If you notice moisture in any of your PTAC units, it may be due to issues such as leaks. Excess moisture can lead to mold or mildew buildup around the vents. One common cause of high humidity in the unit is a malfunctioning evaporator coil that fails to properly dehumidify the air.

When the evaporator coils freeze, they’re unable to cool or remove moisture from the air effectively. To prevent mold growth and other moisture-related problems, be sure to perform regular maintenance and clean your PTAC units frequently.

Tripping Of the Circuit Breaker

So you’ve noticed your PTAC unit circuit breaker is tripping, but you do not know what is happening. PTAC units will always trip the circuit breaker if they pull in more amps than the breaker is rated for. The trips happen to protect from overcurrents, which can damage your unit and potentially cause fires.

Here are some other ways your PTAC system may trip the circuit breaker:

1) Dirty outside unit

2) The compressor has trouble starting

3) Motor has shorted

4) The compressor is grounded

5) Dirty air filter

Formation of Ice

When airflow from the PTAC units into the room is restricted, the transfer of thermal energy between the unit and the room is reduced. This causes most of the cooled air to remain near the evaporator coil, leading to a drop in temperature around the coil. This, in return, causes the formation of ice which gradually continues to form, causing the PTAC unit to freeze up. You can stop the formation of ice and your PTAC unit from freezing up by either:

Letting your PTAC unit defrost.

Changing your filter if it’s dirty.

Opening all the closed supply vents in your room.

Make sure no drapes or furniture are blocking the return vents.