The proper functioning of an air conditioning system is critical during the summer months when temperatures rise to unbearable levels. An AC system that blows hot air, has a low cooling effect or takes a long time to cool a room might be an indication of low refrigerant levels. And, while a professional AC technician can refill refrigerant, some DIY enthusiasts can refill refrigerant themselves.

In this article, we will provide a comprehensive guide on how to refill AC gas.

Step 1 – Turn off the system

Before refilling the refrigerant, it is essential to turn off the air conditioning system. This step is crucial for your safety as refrigerant is a toxic substance that can be harmful if inhaled. Turning off the system ensures the compressor does not draw in refrigerant using the low-pressure port.

Step 2 – Locate the low-pressure port

The next step is to identify the low-pressure port of the AC system. The low-pressure port is where refrigerant is introduced into the system. It is located on the suction side of the system’s compressor. It is also bulky and has a blue or black cap. You might find it helpful to consult your owner’s manual or an online guide for more information.

Always ensure you don’t accidentally remove or unscrew the high-pressure port. The high-pressure port is for venting gas from the system, and this could cause harm.

Step 3 – Obtain the Correct Refrigerant

After locating the low-pressure port, it is time to acquire the correct refrigerant. There is a range of refrigerants in the market, and buying the right one can be a daunting task. However, the easiest way to determine the correct refrigerant for your AC system is to refer to the owner’s manual. If you cannot find the owner’s manual, a professional technician or a hardware store could provide guidance.

It is important to note that mixing different forms of refrigerants can have adverse effects on the compressor and the environment. Therefore, ensure you have the correct refrigerant to avoid any complications.

Step 4 – Prepare the Refrigerant

When using a new refrigerant canister, ensure the canister is upright and shake it well to mix the contents. In most cases, the refrigerant will have to be injected into the canister through a special hose. After injecting the refrigerant, attach the hose to the low-pressure port.

Step 5 – Refilling the AC system

Before introducing refrigerant into the system, it is essential to check the low-side pressure. The low-side pressure gauge should read between 25-45 PSI when the compressor is off. While this is not an accurate pressure gauge, it is a safe range for a typical AC system.

After checking the low-side pressure, it is time to refill the refrigerant. To refill, follow these steps:

• Turn off the compressor
• Attach the hose from the refrigerant canister to the low-pressure port 
• Open the valve on the refrigerant canister to allow the gas to flow through the hose and into the AC system.
• Squeeze the trigger at the end of the hose to start injecting the refrigerant.
• Monitor the gauge for fluctuations. The gauge should indicate a gradual increase in pressure and temperature.

Ensure you maintain the correct refrigerant pressure. Too much pressure can damage the compressor while low pressure can reduce the AC system’s effectiveness.

Step 6 – Monitor the System

After refilling the refrigerant, close the valve on the refrigerant canister and detach the hose from the low-pressure port. Finally, check the AC system to ensure normal operation of the compressor. The AC system should blow cold air and the room’s temperature should be at the desired level.

It is also essential to monitor the AC system after refilling the refrigerant. If the system appears to indicate similar problems to before, it might be an indication of a leak. Refrigerant leaks have adverse effects on the environment and should be fixed as soon as possible.

Conclusion

Refilling AC refrigerant can be an easy task, but it requires careful planning and attention to detail. The consequences of not adequately refilling the refrigerant can result in a poorly functioning air conditioning system. Moreover, using the wrong refrigerant can damage the compressor and, in the long run, the environment.

While this article provides a comprehensive guide on how to refill AC gas, it is always advisable to consult a professional technician, especially for complicated AC systems. Professional technicians have the expertise and equipment to handle complicated HVAC systems.