How to Fill Gas in Your AC Unit – A Detailed Guide for Beginners

Summers have already begun in Pakistan, which means most of us are relying on our cooling units and air conditioners to provide some relief from the deadly heat. Quite recently, we had discussed some hacks and maintenance tips to repair your ac at home and a guide for a DIY air cooler to keep you cool this season. Continuing with the same efforts, here’s a detailed guide for filling gas in an AC unit. 

As per usual, we will divide the blog into different segments to help you get acquainted with the basics. We will begin by giving you a list of necessary equipment and tools for your safety and for refilling gas in an AC unit. Afterwards, we will define the common types of air conditioner gases used in Pakistan, along with their rates. In the end, we will share the procedure for filling gas in an air conditioner. 

So, without further ado, let’s get refilling! 


Man holding manifold gauge kit
Have everything in place before starting the process

It doesn’t matter if you are doing this for the first time or you have been doing this for a long time – safety should be your top priority in all cases. We have split this list into two sections to make sure that you know everything there is to know about your safety, and we will then list the tools that are used for refilling gas in your air conditioner.


Here’s a list of safety gear that you will need to protect yourself from any unforeseeable accident: 

  • Protective gloves 
  • Safety glasses 
  • Face mask 


The list of tools and equipment you will need for refilling gas in an ac unit is mentioned below:

  • Vacuum pump with 1-4 horsepower
  • AC manifold gauge kit
  • Refrigerant tank 


Manifold gauge kit placed on refrigerant tank
Refrigerant gas is usually available in 13.5 kg tanks

If you are a novice, then please keep in mind that air conditioners are of different types, and not all of them support common refrigerants. The most common type of refrigerant used in Pakistan is R22 – also known as Freon in the local lingo. Made from hydrochlorofluorocarbon, this gas is subdivided into two categories: Chinese R22 cylinder and Honeywell USA R22 cylinder. 

The standard weight in which refrigerant gasses are sold is a 13.5 kg cylinder. This size is enough to refill the gas in at least ten air conditioners of 1 ton each. The price of a 13.5 kg Chinese R22 cylinder in Pakistan is around PKR 4,000, while the same sized cylinder of Honeywell USA R22 is sold for PKR 6,000. 

Comparatively, the cost of filling gas in an AC is around PKR 6,000 to PKR 8,000 if you get it done by a professional.

By now, you must have developed a better understanding of the essential tools and types of refrigerants used in Pakistan. Let us now take a look at the detailed procedure for filling gas in an air conditioner unit. 


Man filling gas in ac
A leaking ac can increase your electricity bill

Did you know that a leaking AC unit can cause an unusual hike in your electricity bill while simultaneously decreasing the life of your cooling box? Well, now you do! 

Before we begin detailing the ways to minimise these problems by yourself, how about you take a look at our recently published post where we have shared some smart ways to reduce your electricity bills. We have also shared a detailed guide on how to keep your home cool during this summer without using an air conditioner.  

Now, let’s pick up from where we left off. If you notice signs of leaks in your air conditioner, immediately pay attention to this issue and get it repaired or fixed as soon as possible. That being said, here’s how you can take matters into your hand by following the below-mentioned ac gas filling process:

  • Step 1: Locating Suction and Discharge Lines
  • Step 2: Unscrewing the Bolt 
  • Step 3: Connecting the AC Manifold Gauge 
  • Step 4: Knowing When to Stop 


Location of suction and discharge lines in compressor
Suction and discharge lines are situated on one side of the compressor

Filling gas in a split air conditioner is an easy task provided you have the right tools, and you are good at locating important parts. As such, the first step is to locate the suction and discharge lines. You will find them sitting at a corner of the outdoor unit – as shown in the image above. 

Located on either the top or bottom of the discharge line, the suction line is used to refill refrigerant gas in your cooling unit. It is usually cool to touch while the discharge line is usually warm.  


Once you have located the afore-mentioned lines, it is now time to unscrew the bolt of the suction line after removing its top cover. This screw is a gateway for the refrigerant to flow in and out of the AC, so loosening this will enable you to start the refilling process. 


The third step for refilling gas in an AC unit is to connect the AC manifold gauge kit with the suction line. This step is critical, so you have to be vigilant and specific while doing it. Make sure you are wearing your safety gear at all times. Remember to only loosen the suction line, do not remove it at any cost. 

On the left corner of the suction line, you will find another bolt – remove it and connect it with the red-coloured hose of the AC manifold gauge. Now, connect the yellow hose to the vacuum pump. This will allow the AC to remove the air from and release all the moisture inside the compressor, which can damage it during the process. Turn off all the AC manifolds. After you are done, follow the below-mentioned directions:

  • Disconnect the yellow-coloured hose from the vacuum pump and connect it to the refrigerant tank [if you have two-hosed kit]. Now, loosen the screw of the yellow-coloured hose, which is situated at one end of the manifold kit.
  • Turn on the cylinder knob for a second to remove all the air from the pipes and tighten the screw of the yellow hose right after you have turned off the cylinder knob. 
  • Open the low side screw of the manifold for not more than 5 seconds and close it immediately. 
  • Turn on the AC and wait for the compressor to start. Once it kicks in, turn on the regulator situated at the low-side of the manifold. Keep it running for at least 4 seconds and turn it off for 2 seconds. 
  • Keep repeating this process until the pressure on the gauge settles between 60-70 PSI. Not more or less than that. 
The colour of the hoses and the position of suction and discharge lines may vary from brand to brand.


Right after you have reached the desired pressure, follow the steps mentioned below in the exact order: 

  • Turn off the manifold regulator. 
  • Turn off the refrigerant tank knob.
  • Detach the red hose from the suction line and yellow hose from the refrigerant tank.  
  • Secure everything in its place. 
Pro tip: AC refrigerant is never refilled all at once, and it is rather filled in small intervals. Releasing all the gas can severely damage the compressor, so be patient.  

This concludes our post on how to add refrigerant to the AC unit. We have shared a detailed guide that can help you understand the procedure for filling gas in an air conditioner with a few simple steps. This knowledge can help you and your friends save a lot of money. If you have any further questions regarding this blog, you can write to us at

Moreover, we have also shared some ways to maximise the cooling of your room cooler, so check out our post if you want to run your swamp cooler efficiently. For more tips on taking care of your home electronics, keep visiting My Blog – Pakistan’s most trusted source for everything lifestyle. Do not forget to like our Facebook page. 

Disclaimer: Air conditioner gas or refrigerant can be toxic. It can also cause frostbite. So, take all the required precautions or have an expert guide you for the first-time. doesn’t take responsibility for any accident, so attempt it at your own risk. The price of gas mentioned in the blog was shared by several wholesalers. does not take any responsibility for the accuracy of these prices.  

Kashif Qureshi
Salam! I am an i-National Marketeer, Business Developer & Realtor Pakistan with a great career history of 19 years. Having lived, studied and worked in multiple countries, I am multi-lingual and I welcome you to my website.

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