While this task is usually performed by a refrigeration mechanic a lay person can complete it by purchasing a freon kit.
Put freon window air conditioner.
Turn on the air conditioner to high for a few minutes and then connect the yellow tube to the freon bottle.
Adding freon to a window air conditioner involves cleaning the air conditioner attaching a new freon container and allowing it to intake new freon until the container is drained.
Recharging the refrigerant on a window air conditioner is not something done often with most people buying a new unit when an old unit fails.
How to recharge your home air conditioner.
The process can be dangerous so hire a qualified professional if you feel unsure about what to do.
Windows air conditioners can however be recharged with refrigerant and be put back to work cooling a room or space.
Loosen the yellow tubing at the gauge for just a second and then tighten it back up.
Open the freon valve.