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How To Recharge a Window Air Conditioner


An air conditioner is necessary for our lives, as we cannot function without it in high temperatures and hot weather. However, after some time, our air conditioning unit would lose its capacity to keep enough cool air inside the room. If this happens, we should know there are ways to get the most efficiency out of our unit. 

In this article, we will discuss how to properly recharge a window air conditioner without breaking your budget. 

Step-by-Step Procedure for Preparing a Window AC Unit for a Recharge

window AC unit

Your window air conditioner can be a little complicated to understand, but don’t be intimidated. There are simple steps to follow in recharging your window unit.

Get the Necessary Supplies

To get into the actual process of recharging a window air conditioner, you must know the things that you will need, such as

  • Protective gloves 
  • Protective eye glasses 
  • Screwdriver 
  • Leak detector 
  • Refrigerant 
  • Freon kit 

Know the Manuals 

Knowing the manuals is one of the primary things you should do to recharge window AC units. An owner’s manual acts as a written instruction to easily handle a window air conditioner. The information in the document is intended to minimize the risk of damage by showing them how to use the aircon properly.

Put on Your Gloves and Protective Eye Glasses 

Some chemicals in a window air conditioner, such as freon, a harmful toxic that helps lower the temperature and produces cold air. That said, you must protect yourself and take all the necessary precautions by wearing thick gloves and protective eyeglasses to prevent severe injuries. 

Check Your Air Filter

A dirty air filter is one of the most common problems with window air conditioners. As a result, a window unit fails and decreases its energy efficiency due to accumulated dust. 

Most small AC units have a removable air filter. Try removing and cleaning it according to instructions.

Check for Potential Leaks

It is essential to check for potential leaks before recharging a window air conditioner. Leaks can vary from refrigerant leaks to bubble formation. Sometimes, a very slow leak might occur after opening your AC unit, so it is important always to check the user manual.

You can use a few methods to find the leak sites inside your window AC unit, such as:

  • Soap: Make a solution of soap and water to create a lubricant. Switch on the system and lubricate the refrigerant transmission gear. A bullet piercing valve, Schrader valve, air handler, and other inner parts of window air conditioners are considered gears. After you spill the mixture all over the refrigerant gear, turn on the unit and check where the bubbles form.
  • Leak Detector: Turn on your window unit and shield it from direct drafts. Switch the leak detection and place its probe near your AC’s outdoor unit. The device will automatically provide a notification if there is a leak. 
  • Nitrogen: Close the valves that link to upstream or downstream apparatuses, pressurizing the unit with nitrogen and checking the pressure after a few minutes. Once there is a significant pressure drop, it only means that there is a leak. Note: Only professionals should do this method.
  • Fluorescent Dye: This approach is simple enough for beginners to understand, as it only requires filling the system with a tiny fluorescent dye and switching it on. The dye circulates with the refrigerant to locate the source of the leak in your window AC unit. You can also use a leak-detection flashlight or an ultraviolet lamp.

Fix the Leak

After locating the leak, it’s time to fix it to recharge a window air conditioner.

If your window AC unit has a very slow leak, then it is unnecessary to fix it. Instead, you should boost the AC system since it will be enough to compensate for any refrigerant leak. However, if your air conditioner has a very significant leak, it is required to solder the area from which the refrigerant is leaking before the refrigerant recharge. 

Connect the Valves to the Compressor

Connecting the valves to the compressor is the next step to recharge a window air conditioner. If you need more confidence in doing this, you can scan your user manual to see where the compressor and service valve are. Often time, they have two lines nearby.

After locating the compressor and service valve, attach the compressor line to the service valve from your freon kit and connect the other line to the tap valve. Notice that your AC system has one free line connecting the tap valve and compressor. 

Connect the Valves to the Freon Kit 

Another important step is to connect two valves to the freon’s container. If you are unfamiliar with it, fret not, as almost all freon kits provide step-by-step procedures. You just need to follow and use the detailed diagram from your freon kit to see the position of the refrigerant freon tank between two valves.

Then, ensure that the valves are connected properly.

How to Recharge a Window Air Conditioner

After preparing your AC, you can now turn on your window air conditioner unit and ramp it to its highest power setting. The service and tap valves directly connected through freon lines to the freon tank will start flowing from the tank and into the unit. 

Do not forget to check your unit’s manual to see the amount of freon required for your AC unit. Once the tank indicates that the matching limit has been reached, power down and unplug the AC unit from the wall socket. Recharge the window air conditioner by removing the valves and turning them back on.

Once your unit starts blowing cooler air, you have successfully recharged your window air conditioner unit. 

What to Remember in DIY Recharging of Window AC Units

Now you know how to recharge a window air conditioning unit, remember the following to ensure a safe and comfortable household.

  • The refrigerant is located in a closed-loop system, so its performance will only decrease if there’s a leak. Once you notice a freon deficiency, identify and repair it immediately before you recharge a window AC. Freon is hazardous to a person’s health, so it is essential to address this concern as soon as possible.
  • If your window air conditioner produces hot air instead of cool air, immediately contact a local technician to assess the leak. The expert may try the HVAC tech method to fix the leak. This will detect and fix the problem by adding the right refrigerant. 
  • Using the same refrigerant is important in recharging your window AC. Some older window units use R-22 refrigerant, while most small AC units use R-410A. Check the label of your window air conditioner to see the type of refrigerant your air conditioner unit uses. 
  • Each air conditioning system has different pressures, which will change depending on the outside temperature. For example, if a unit is low on refrigerant, the pressure will be lower, and the system will not work. On the other hand, If a unit is overfilled, the pressure will be too high, and the system will not work. In other words, an air conditioner needs correct pressure to work efficiently.

Final Thoughts

A window air conditioner lasts for a long time if maintained properly. Maintaining your unit regularly is the best way to keep it in great shape. This not only maintains its cooling power but also extends the life of your appliance.

Before you shell out for a full replacement, see if you can make a repair by recharging your window air conditioner. Always consult a local aircon technician to ensure that the system working properly. 

However, if your air conditioner consistently fails, you can get a new unit instead of risking your health.

JP Reyes

JP has been in the aircon industry for almost as long as he has been alive. As a child JP would help his tatay fix aircon units at their junk shop in Cavite. After graduating UP in the early 2000's, JP then started his own Aircon servicing business and within 5 years had 10 shops in 8 different cities. Fast forward to today and JP brings all his experience and expertise online to give readers trustworthy advice and reviews about Air-conditioning buying, servicing, cleaning and repair in the Philippines.

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