About Vacuum Pumps
Sludge, rust, and ice are just what an air conditioning system doesn't need. A vacuum pump is used by modern refrigeration and air conditioning systems to combat moisture in the system. The problem is that, for greater energy efficiency, modern systems are more airtight than older ones. This means that moisture accumulates easily, precipitated from the cool air. The water doesn't stay liquid, but is transported through the system as a fine ice mist, almost like snow. It can corrode the system, or, even worse, combine with refrigerants to form hydrochloric acid—definitely not good! A HVAC vacuum pump removes water from the system by dropping the air pressure and letting the moisture boil off, even at low temperatures. An air conditioning vacuum pump of various capacities is usually available on eBay. The strength of the vacuum pump you need depends on the system. For a home AC system, about three or four CFM is enough. Keep it high and dry.