[Shotimes] A/C System Vacuum Pump

[Bill Strobel]

Most people think the reason that they pull a vacuum on an A/C system is to check for leaks.  That is one of the reasons to be sure, but the primary reason is to rid the system of water.  By pulling a vacuum you are lowing the pressure inside the A/C system and are thus lowering the boiling point of the water inside the system also.  This converts any water to water vapor which is easily removed by the vacuum pump.  The longer you hold the vacuum the more complete the water evacuation is, the better your A/C system will cool, and the longer it will last.  Water when mixed with both R-12 or R-134a forms a highly corrosive acid that eats things like the condenser, evaporator or the lines and can cause leaks.  If the system has been open to air it is best to pull a vacuum on the system prior to recharging.  If the system is fully charged and is not cooling sufficiently an evac, pulling vacuum for an hour or so and then a refill with virgin or recycled gas (gas that has been put through
 the recycle machines filter and drier) will sometimes work wonders for the system.  If you have free access to a recycle machine this is great preventative maintenance too.  Do not overlook your community college.  They may have an auto A/C course with a machine.  If you take the class you can evac all of your cars or changeover from R-12 to R-134a for the cost of just the 134a.  I took the class last year and did a bunch of cars, plus I can use the machine during the day if I coordinate with the instructor ahead of time.  134a is on borrowed time in the US.  The Europeans have adopted high pressure CO2 as a their refrigerant standard and it makes no sense for the manufactures to build two different systems.  Look for 134a machines to be on sale big time once the manufactures announce they will go with CO2 across the board.  Right now everyone in the industry is taking a wait and see approach and very few are investing in any new machines or equipment right now.           

Bill Strobel
Independent Towing
Fayetteville NC
		
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