Adding freon to window A/C

Does anyone know how to check and add Freon to window a/c units?

 

I think those are designed as throw away units rather than repairable units.

 

Looks like you can add Freon. There are different types of Freon in use. Some much more expensive so you really want to make sure you get the correct type for your unit so you do not waste money.

 

I had bought a 3 year old window unit. It pumps nice and cold then it starts to freeze up. I have to turn it to fan then back to cold about 20 minutes later. Doing some research on Google I am finding that it may need Freon. According to the video above it says it should be hissing noise if there is a Freon leak. I have not heard a hissing noise (not even a very low noise).

 

It may be dirty inside preventing the air flow from taking the cool air out effectively.

 

http://asm-air.com/airconditioning/air-conditioner-freezing-up/

1. Insufficient air flow across your air conditioner’s evaporator coil can cause it to freeze up. In a split air conditioner (the most common type – see: What is a Split Air Conditioner?), our air conditioner is designed to drop the temperature of your house by taking heat from it. If your air conditioner is not properly blowing your inside air over the evaporator coil, then this heat exchange cannot take place and the Freon that should be removing heat from your home is not. Over time, its temperature will continue to drop and your air conditioner can freeze up.
2. If your air conditioner is low on refrigerant, then your air conditioner can freeze up due to lower pressure inside the system itself. This is because now there is less Freon in your system, but it is still being forced to expand the same amount – more expansion equals a coolertemperature. As your air conditioner’s evaporator coil drops below freezing, the moisture in your air will freeze as it comes into contact with your coil causing it to ice up.
3. Air conditioners are designed to function in a very specific temperature range. If you are running your air conditioner when the outside air is below around 62 degrees, then the pressures inside of your system will drop and this can cause a freeze up of your central air conditioner.
4. Mechanical failures can cause your air conditioner to freeze up. If there is a kink in your refrigerant lines, a blower fan that is not running or is dinged and out of balance, or a clogged filter dryer? These too can change the pressure in your system and make your central air conditioner freeze up.