Vacuum Pumps from Amazon.com
No one likes to have to spend a single day in the heat of summer without a working air conditioner. One of the easier things you can do to increase the efficiency of your system is to attach a vacuum pump. Within an hour, it can usually cool your car to a very comfortable temperature.
Vacuum pumps perform two duties that help your AC unit run efficiently. They remove any water, air, or gas from the unit, keeping them from becoming charged with refrigerant. They are also used to freeze water vapor in the system to control the pressure within the unit. As the pressure drops, water will boil at room temperature and escape the system as vapor.
One sign that you need to use a vacuum pump on your unit is frozen or corroded internal coils. The coils freeze when the pressure is not low enough to vaporize any liquid. You will also need to use a vacuum pump when you have had the refrigerant drained for any type of service. Allow the pump to run until the system has been purged of all contaminants and has reached the correct internal pressure.
It is important to have the appropriate size of vacuum pump for the job, as your unit will never reach its proper internal pressure otherwise. Amazon.com offers a wide range of vacuum pumps. You are more likely to find units that will work with an older air conditioning system than in your local hardware store. You'll also find it easy to get newer models, as well. In most cases, you will most likely receive your purchase within a week; if it is urgent you get it faster, you can opt for faster shipping.
Instead of suffering through a hot summer with an air conditioner that is costing you money but not doing its job, use a vacuum pump to make sure the system is clean of any liquids or air. If you still have the literature that came with your system, it should tell you what you need when a vacuum pump is necessary.