PTAC Unit Compressor Not Working – Why And What To Do?

PTAC single-unit compressors are great for heating and cooling single rooms. But, like any other conditioning appliance, a PTAC unit compressor can malfunction. Why would this happen, and how do you fix it? We did research to bring you solutions.

Your PTAC unit compressor may stop working due to the following reasons:

  • Faulty Control Board
  • Broken motor
  • Faulty compressor
  • Poor installation
  • Dirty frozen coils

Continue reading to understand what causes your PTAC unit compressor to stop working and how to fix these problems. Maintenance tips that help your compressor function optimally and extend its lifespan are included.

Back view of a PTAC unit on a cart, PTAC Unit Compressor Not Working - Why And What To Do?

Why Your PTAC Compressor Is Not Working And How To Fix It 

A packaged terminal air conditioner (PTAC) is a self-contained heating and cooling air appliance. It is designed mainly for use in commercial buildings such as hotels, apartment buildings, offices, condominiums, and hospitals. 

PTAC compressors are single units installed in walls and are used to condition individual rooms. They are energy efficient, bringing the utility costs down. They are also easy to install, as they don’t need any ductwork. 

Similar to other conditioning appliances, your compressor may malfunction. Some ways this can happen are when it stops blowing air, has shorter conditioning cycles, or sometimes has water leaks. 

The causes of your compressor not working and how to fix it is discussed below:

Faulty Control Board

PTAC electronic control board with all factory cables still intact

The control board is the brain of your PTAC unit. When it stops working, the whole unit stops working. 

There are several reasons why it would malfunction. One of the reasons is that it degrades with age until it finally stops working. Other reasons the control board would fail include:

  • An electrical surge with a higher voltage can damage the circuitry
  • The input of a wrong voltage
  • Damaged wires in the board
  • Damage by insects inside the AC can cause short circuits

A control board can be repaired so that it works again. However, this is best done by a trained professional. 

Broken Motor

The blower motor could be faulty when your unit produces heat but not airflow. A malfunctioned condenser or evaporator could also be the problem. 

Check out this capacitor on Amazon.

Sometimes the capacitor, which turns on your motor, could be harmful. It may be the only item you need to replace. 

Air conditioner outdoor unit compressor capacitor motor

The motor like the one below might also be broken. If this is true, you will feel the heat coming from it when you are near it. When you move a few inches away, you will not feel any heat coming out of the unit.

Have a look at this electric motor for a compressor on Amazon.

The unit may cool a room less efficiently when the condenser is faulty. The evaporator, too, may behave the same way with no cold air blowing. With time these parts wear out and end up malfunctioning. They will also need replacement. 

Faulty Compressor

Refrigerant compressor on a small PTAC unit

The compressor can last the lifetime of your PTAC unit. However, it can still get damaged due to wear and tear and poor maintenance.  

When the compressor stops working, you may hear strange noises from the unit or notice refrigerant leaks. Restricted airflow and inadequate temperatures are other problems that can occur in your unit. 

Have a look at this multimeter on Amazon.

Because the compressor can cause myriad problems, it is best first to test it using a multimeter. That way, you will determine if the problem is the compressor or another related part. 

Diagnosing a compressor is easy but also confusing. You may need a professional to test it for you. 

Replace it if it short circuits or is grounded. You might also find out that the capacitor is the one that has a problem. A faulty pressure switch is another culprit. In such a case, you will only need to replace these parts, not the compressor. 

Poor Installation

A poorly installed PTAC unit may blow out water droplets or spit water through the grill. It could also leak moisture at the bottom. 

Condensation takes place in the coils when your unit is cooling. The condensed moisture drains into a drain pan at the bottom of the unit. When correctly installed, the pan drains the moisture outside. 

When installed incorrectly, the fan will blow the moisture droplets out through the front grill, although it may sometimes come out through the bottom of the unit and onto the floor. 

Spitting happens due to the unit tilting too far inwards. To correct this, try tilting it back into position. Read the manual for instructions on how to do this.

A clogged drain can also block moisture from draining outside. This can occur due to the accumulation of dust and debris. To fix this, clean the drain pan, and do it often to prevent future clogging. 

Dirty Frozen Coils

When you notice frozen refrigerant coils in your PTAC, there is a good chance you have not been cleaning them. When this happens, your unit will not cool properly. 

Furthermore, the moisture can freeze in the drain pan, causing a leak at the bottom of your unit due to moisture condensation. To solve this, uninstall it, clean it, and re-install it. 

In some situations, there might be a refrigerant leak. You can repair it if you are up to the task or call a technician to seal the leak or replace the coils. 

Maintenance Tips For Your PTAC Compressor Unit

You most likely want your unit to serve you for many years. For this to be possible, you must clean it at least once a month. 

Cleaning your unit is not difficult and takes around thirty minutes . Below are maintenance tips that can help you achieve this:

Clean The Air Filters

Checking air filter on a PTAC unit to make sure vents are clean for proper ventilation

The air filters prevent dirt and debris from entering a room. This is essential because it can prevent respiratory issues and allergies. Dirt and debris can clog the filters, leading to poor conditioning performance by your unit.

For continued efficiency, clean the air filters each month. Start by turning off the unit. Remove the filter and vacuum it to get rid of the loose dirt.

Afterward, use soapy water and gently wash it. Alternatively, soak it in a mixture of equal parts of water and vinegar for about an hour.

Rinse it using a hose to spray clean water and set it aside to dry. Re-install it after it is completely dry. If it's damaged, throw it away, and buy a new one.

Clean The Vent Screen

The vent screen prevents dirt, debris, and other harmful particles from entering your unit. These substances can accumulate, blocking your screen. As a result, the air entering your room will not be clean.

To clean the screen involves touching the inside of the unit. You should switch off the appliance to prevent potential electric shocks.

Read the manual for instructions on how to access the vent screen. Open up the front, and use a vacuum to clean it. A cloth is equally good to use. Close up the unit and switch it on.

Clean The Front

Unplug the unit. After returning the cabinet front, which you removed earlier to access the screen vent, clean it with a damp cloth. Also, clean the grill. As you are cleaning, ensure water does not touch any electrical components. 

Maintenance Each Year

Call a technician to check your unit at least once every year. The technician can repair any issues early before they damage your unit.

In addition, it is good to deep clean it once a year. Every three months may be better, especially for hospital units, to help patients recover faster. 

In Closing

PTAC unit compressors are primarily found in hospitals, hotels, apartments, offices, or other commercial buildings. They are preferred because they are energy efficient and easy to install.

Newest GE PTAC unit installed under a window

Despite the advantages of these units, they can malfunction for several reasons. You can resolve the problem yourself if you have the skills. However, as always, it’s better to call a qualified technician.

For your PTAC unit compressor to last a long time, you must maintain it in good condition by regularly cleaning it and calling a technician to check it every year.

To learn more about PTAC unit compressors, check out our previous posts below:

PTAC Unit Tripping Breaker Why And What To Do

Can A PTAC Unit Be Recharged


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