How to Recharge an AC Unit

Published by 
Last updated: 
April 7, 2018

Most of the air conditioning units these days are centralized in nature. If you come home after a long day at work or from a walk in broad daylight, it could not get more annoying to see the AC at your place not working or getting charged. There is a complicated phenomenon involving the transfer of heat upon which the air conditioning units function. All of this is facilitated by a refrigerant. And whenever there is a decline in the refrigerant level, it is a clear indication that your centralized AC unit needs a recharge. It happens as the transfer of heat does not occur with low refrigerant levels. That's why it's important to learn how to recharge AC unit.

Since the options are plenty in number, it is extremely important that you know the kind of refrigerant the AC unit uses. If you use a wrong combination, it would be worse than having a non-functional air conditioning system. If all of this seems too technical to you, just call in an expert who would get the job done for you. But if you decide to do it yourself, then the following steps could be of great assistance to you.

Person's hands fixing an AC unit

How to Recharge an AC Unit

Step 1. Locate the Compressor

Almost every air conditioning unit comes with a documented manual for help. If you are not aware where the compressor is, then use the manual and locate it. In its appearance, the compressor looks identical to a metal cylinder. Here, some information on troubleshooting an AC compressor might come in handy if you're encountering issues with it.

Step 2. See If Everything Works

An important step to remember before adding the coolant is to check if all the remaining components are in a functional condition. It is crucial because if you add the coolant and the root cause is something else, then it would mess up the whole system in a bad way. In that case, you would be looking at not only more effort but also more money to fix it. But once you identified that the cooling agent is the root cause, proceed to step 3.

Step 3. Locate the Service Valve

The next step is to find out where the service valve is. Once you have located it, connect it to the compressor line in the AC unit. If you are not totally sure about this step in how to recharge an AC unit, you might either use instructions on the kit or use some reviewed online resources to complete the task.

Step 4. Locate the Tap Valve

The next step is to locate the tap valve. Use the instruction manual if you have difficulty locating it. Once you find out where the tap valve is, connect it to the remainder of the compressor line.

carrier ac

Step 5. Add Cooling Agent

The next step when learning how to recharge an AC unit is to add the cooling agent to the lines. To accomplish this task, you need to attach the container with the cooling agent to both the valves you installed in the previous steps. In simple terms, the air conditioner will act as a potent force to let the cooling agent (like freon) inside the unit. There will always be an instructional manual and if you encounter any difficulty with anything, follow the instructions.

Step 6. Let the Cooling Agent Flow

At this stage of learning how to recharge an AC unit, you have completed the installation of a brand new refrigerant to the air conditioning unit at your house. For now, just let the free flow of the cooling agent happen. To accomplish this, the only thing you need to do is to set the air conditioning unit at the highest possible setting once you turn it on. This simple step would let the cooling agent into the air conditioning unit while the AC unit gets recharged automatically.

Step 7. Unplug the Cooling Agent and the Valves

Once you identified that the air conditioning unit has consumed all of the cooling agent, then just turn off the ac unit. Finally, you just need to unplug the cooling agent container as well as both the valves.

Safety Precautions

Learning how to recharge an AC unit is a skilled job but it could be risky in some situations. You need to be extra careful while dealing with the refrigerant because of its toxic nature. If by any chance you inhale it, it might have serious repercussions on your health. Even while performing a simple task of checking the older refrigerant or removing it, cover yourself appropriately with either gloves or mask. It might be a bit inconvenient, but it will only protect you from any possible reaction.

When you talk about the legality of performing such tasks on the air conditioning units, not all areas are free zones. There are some geographical locations where you need an official license to accomplish the task. Only because most of the refrigerants are available as over the counter products does not imply you could start using it if you decide to purchase one. Do your own diligent research and be very cautious about the state laws where you reside which clarify how to recharge an AC unit.


Even though all of the above tasks could sound very simple in theory, it might not be the case all the time. The reasons for an AC malfunctioning could vary depending on what’s wrong. However, all the detailed steps mentioned above could give you a good head-start to the project.

But if you feel you are not completely sure about how to recharge an AC unit on your own, do not attempt it as it might potentially mess something else in the air conditioning unit. There are plenty of skilled professionals out there. They can do the job for you for a fee while you relax on your couch.

Image source:

All Things HVAC

We formed this web site so consumers could have an educational place to go for good, solid information.  We are not trying to sell you anything.
Copyright © 2024 AllThingsHVAC. All Rights Reserved