Tips for Repairing PTAC Units

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It’s a fact of life: everything eventually breaks down. The same goes for your air conditioning unit, and it won’t always stop working at a convenient time. While you might expect some common problems like a broken blower motor, other issues might surprise you.

When you’re staring at a PTAC (Packaged Terminal Air Conditioner) that’s short cycling, not blowing air, or even leaking water, it’s good to know what you can fix yourself and when it’s time to call a professional. 

Your PTAC unit won’t last forever, but that doesn’t mean it can’t serve your space for a long time. In addition to repairs, continued maintenance will help extend the life of your unit for years to come. Let’s look at how you can diagnose and repair your unit, the best maintenance practices for PTACs, and when you need to call a technician for help.

The Troubleshooting Process

If you’re using a PTAC unit with a digital interface, you can diagnose common problems using the unit’s built-in self-diagnostic mode. This function allows your PTAC unit to display a series of error codes for common problems. Each error code corresponds to a specific issue with the unit and acts as a primary reference for troubleshooting. You can then take the necessary steps to repair the issue if possible.

To put your unit into self-diagnostic mode, follow the instructions in your user manual. For most Amana PTACs, this means holding the up and down arrow buttons at the same time and pressing the “cool” button twice. After a few moments, the unit will run a diagnostic test and display an error code. 

While this is a great first step to take for digital units, keep in mind that it won’t catch everything. Some problems aren’t digitally traceable, and you’ll sometimes need to take a deeper look at the machine to figure out what’s wrong. 

This is also the case for repairing units with a non-digital display, or those that operate using bit switches. For both digital and non-digital PTAC units, our repair technicians at PTAC4Less follow a manual troubleshooting process in which they check all of the features of the machine until they find the problem. That process looks something like this: 

  • Check Heating. The unit should heat up the space around it to the correct temperature you set for it.
  • Check Cooling. The unit should be cooling at a 25°F differential from the outside temperature. For example, if it’s 80°F outside of the building, it should be cooling to at least 55°F. 
  • Check the Airflow. The unit should not only be producing hot or cold air, but also blowing it out the front of the unit. 
  • Check for Short Cycling. The unit should also run long enough to pull moisture out of the air and not shut off too early (a.k.a Short Cycling). 

After this, our repair technicians will check some of the most important mechanical parts and make sure they are working properly: 

  • Check the Wiring. Make sure all wires are installed in the right places and none of them are corroded. The power cord should also be the correct gauge for the wall socket. 
  • Check the Thermistors. Each PTAC should also have the required thermistors to properly read and respond to the set temperature for the room. 
  • Check the Compressor. You should also check to make sure the unit’s compressor is still working and running for the right length of time to pull moisture from the air. 

Be sure to check the owner’s manual for your PTAC model. Troubleshooting steps will often be listed there from the manufacturer along with some common repair scenarios.

Most Common Repairs

Once you’ve run through the basic troubleshooting steps, you might be able to diagnose the problem on your own. Otherwise, you might need some additional expertise to figure out the problem. While a complete guide to every repair scenario could fill up an entire handbook, here are some common issues that PTAC owners may experience within the unit’s lifetime.

Bad Control Board

The control board is the brains of your PTAC machine. If it stops working, so does the entire unit. While there are a number of reasons why it might go bad, control boards usually just malfunction with age. In general, the electronic pieces of a PTAC tend to break down well before the mechanical units, so this may be one of the first pieces you need to replace. 

Since most modern control boards are solid state, repairing the control board itself is not worth the time or effort required. It’s best to replace the entire control board, which you can do without taking the unit out of the wall.

The control board is also supported by other sub-level control boards, so be sure to check those as well. You may be able to replace one of the sub-level boards without replacing the main unit.

If you aren’t comfortable working with complex wiring, you might want to contact a professional to replace the control board for you. Otherwise, if you choose to do the replacement yourself, pay careful attention to how each wire is connected to the board. Be careful to connect those wires to the new board exactly the same way as before.

Broken Motor

Sometimes, your unit may produce some heat but no airflow. In this case, the problem is usually the blower motor, the condenser motor, or the evaporator motor. 

First, you can check the capacitor, which helps the motor turn on. If the capacitor is bad, your motor will not start. Sometimes this is the only issue, and it simply needs to be replaced.

Other times the motor itself may be broken. If it is the blower motor, you will likely feel heat when your hand is next to the grill but feel nothing from a few inches away. If the condenser motor or evaporator motor aren’t working, your main heat source won’t work properly either. You will only have a small amount of supplemental heat (usually from the heat pump).

If the condenser motor or the evaporator motor goes bad, your cooling function may not work at all. Because the evaporator motor extracts heat through the back of the unit, you may have other temperature control issues as well. In other cases, a unit with a bad motor might not even run at all.

Because these motors are constantly running while the unit is on, they often wear down much faster and may need to be replaced more often than other parts of the unit.

Malfunctioning Heat Kit

Condensation in some models may cause excess moisture in the bottom of the unit and corrode the heat kit until it stops working completely. When this happens, units with built-in heat pumps will receive heat from the main source, but they will be lacking the supplemental heat from the heat kit. This makes the unit’s heat function noticeably less powerful.

More often, the issue might not be the heat kit itself but the wires that connect to it. When water comes in contact with these wires, it can destroy those connections and their limit switches.

To fix this, you may need to replace the heat kit and the supplemental parts to ensure the unit is back up and running properly.

Less Common Repairs

Other problems related to moisture and improper maintenance may not happen as often if you take good care of your unit. However, there is still a chance you might encounter them one day. Here are a few less common repairs you’ll want to consider during troubleshooting.

Compressor Issues

The compressor is often the toughest part of your PTAC unit. In fact, it should last the full lifespan of your unit unless it gets damaged or poor maintenance affects its performance.

Compressor issues can cause a wide range of problems from improper temperatures and restricted airflow to loud noises and refrigerant leaks. Because of this, you might need to do some more testing to figure out if the issue is coming directly from the compressor or another part of the unit. 

Most of the time, this will require a professional who may use a multimeter to test the Ohms on the compressor. If it goes to ground or short circuits, then it will need to be replaced by a professional technician.

In some cases, your unit might have a bad pressure switch, a capacitor that won’t start the compressor, or an overload. Depending on the issue, you may simply need to replace those parts and put the unit back into service.

Leaking Water

Sometimes, you may find that your unit is blowing water droplets through the front grill (also called “spitting water”). Other times, it could be leaking condensation from the bottom. There are a number of reasons this could be happening.

Most of the time, if the unit is leaking or spitting water, it isn’t installed correctly. During the cooling process, PTACs will create condensation on the coils. That condensation then drips off into a drain pan at the bottom of the unit. If installed correctly into the wall sleeve, the unit should be tilted slightly backward by a few degrees so that water in the pan drains to the outside. 

A unit that is tilted slightly forward may allow the fan to blow water droplets through the front grill. Otherwise, it might simply leak out of the bottom of the unit onto the floor. To fix this, start by checking the angle of your unit and tilting it back if necessary. While different manufacturers have their own recommendations, angling your unit about 2° toward the outside is often a best practice.

Other times, a leaking unit may be the result of a clogged drain pan. Units can often collect dust and debris over time, and if a drain pan is not cleaned this can prevent the water from draining outside. To fix this, you simply need to clean the drain pan, remove any obstructions, and put it back in place.

Frozen Coils

If you’ve ever seen icicles on the back of an AC unit, then you’ve likely seen a unit with frozen refrigerant coils. If this happens, your PTAC unit will often stop cooling or freeze up water in the drain pan and cause excess water to leak from the bottom.

Refrigerant coils typically freeze because they haven’t been cleaned in a long time. If this is the case, you simply need to take the unit outside and clean the coils before reinstalling it.

In other cases, it might be an issue with a small refrigerant leak. If you’re able to patch up the coils yourself, you can install a piercing valve on the suction side of your unit to add more refrigerant. Then, you will need to weld it together afterward.

When we repair coil leaks at our facilities, our technicians will cut off the line to the leaking side of the coils to install an access port. We will then fill the unit with more refrigerant and clamp it back up using a pinching tool. This pinching tool allows us to weld up the hole and seal it tight. When it’s complete, these units come out looking factory-new.

Continued Maintenance Advice

Although knowing how to repair a PTAC unit is useful information, good maintenance practices will help preserve the longevity of your unit and prevent the need for extra repairs. In fact, a well-maintained PTAC unit should last 18 to 20 years.

Here are a few tips for maintaining your PTAC that you can put into practice today.

Changing/Cleaning the Filter

Changing your air filter doesn’t just help with indoor air quality. It also affects the unit’s efficiency and lifespan over time.

Typically, your filter should be changed out or cleaned (if reusable) every 30 days. When your filter goes unchanged for longer than that, it collects a thick layer of dust and other pollutants. These pollutants then build up on the filter and blow off into the air stream. This buildup also restricts airflow through the filter and the coils, causing undue pressure on the compressor. Over time, this pressure shortens the life of your compressor, which can make for a costly repair.

Cleaning the Coils

As outside air continues to blow through the refrigerant coils, they can build up dust and debris just like the air filter. For this reason, it’s important to clean the coils on your PTAC unit at least once every year (if not every six months). This prevents them from freezing or creating pressure on other parts of the unit from restricted airflow.

While you don’t necessarily need to take your PTAC unit outside to clean the coils, it is a messy process that’s far easier to manage outdoors. It’s good to use a cleaning solution in addition to warm water. Any off-the-shelf cleaning product will work, but you want to make sure the cleaner is made specifically for HVAC parts. Although it’s usually best to use a more potent cleaner, you may want to opt for a mild product if you choose to clean the coils inside.

To clean the coils, lather on the cleaner with a rag or soft brush until the dirt, dust, or debris is removed. Leave the cleaner on the coils for the amount of time specified in the cleaner directions. Then, spray it off with a low-pressure hose. Be careful not to use high water pressure, as this could damage the coils.

Before taking it back inside, be sure to read the directions on your cleaning product for how long you should allow the unit to air out before reinstalling it.

Keep the Back Side Clean

Many commercial buildings will have mulching, landscaping, or painting done around PTAC units on the ground floor. Since the back of a PTAC unit is exposed through the external wall, this presents a problem.

Things like mulch, brush, leaves, and paint can all get lodged in the back of the coils and clog them up. This also makes it more difficult for air to flow through the unit, creating extra pressure on the compressor and shortening its lifespan. While you can still decorate the outside of your building, be sure to either complete those projects before you install your units or clean your PTACs soon afterward.

Avoid Oversizing

When purchasing a new PTAC unit, it’s a common myth that bigger is better. In reality, it all depends on the size of the room it’s being used in.

Imagine an indoor space that is 350 square feet. While a unit with 15,000 BTUs may be able to cool this small space much faster than a unit with only 9,000 BTUs, it still won’t run long enough to pull the moisture out of the air. This is what the industry calls short cycling. This not only leaves the room with more latent heat from humidity but also causes mold and moisture problems if not handled properly with an additional dehumidifier.

Even though it may run longer, the 9,000 BTU unit would work much better in a 350 to 400 square foot space because it is properly sized.

When Is It Time to Replace Your PTAC?

Although many parts on your PTAC can simply be replaced, some problems are just too difficult to fix. Many repair technicians would agree that repairing a constant refrigerant leak can be nearly impossible. While a small leak is often manageable, a large or persistent leak that continues to happen for weeks (even after initial repairs) is often not worth fixing. 

This is because refrigerant leaks originate in the coils on the back of the unit. Due to the way coils are constructed, finding the location of the leak can be a real challenge. Unless you are able to change out the coils yourself, this is usually a professional repair job. Even then, you are probably better off to scrap the unit and purchase a new or refurbished unit for around the same price.

Final Thoughts

PTACs are much more complex than many people realize, but they are still fairly easy to repair. If you are mechanically inclined in any way, repairing your own PTAC unit is usually possible through watching a few tutorial videos and paying careful attention to how you install a new part. Some brands like Amana are great investments for this very reason. They perform well and they’re easy to repair. 

That said, repair jobs are tough. It can be difficult to diagnose the right issue without prior experience working with PTAC units. Even then, finding a part for a good price online or in a store can be a nightmare.

If you need help finding brand new PTAC parts at a lower price, we have you covered at PTAC4Less. We also have a wide selection of new and refurbished units available in case you decide it’s not worth fixing. Give us a call or send us an email for repair advice and help selecting the right unit for your space.