purpose of a vacuum pump is to remove moisture and
air from an A/C-R system.
Modern systems are built tighter and charges are more
critical. That means these systems have a greater
sensitivity to moisture and other contaminants, making
thorough evacuation more important than ever before.
Moisture in a refrigeration system, directly
or indirectly, is the cause of most
problems and complaints. First,
moisture can cause freeze-up in a system. Moisture is picked
up by the refrigerant and transported through the
refrigerant line in a fine mist, with
ice crystals forming at the point of
ďFreeze-upĒ is not the only problem caused by
moisture. It can also result in
corrosion, the effects of which are not
apparent until the real damage has occurred.
alone is bad enough, but combined with
refrigerants containing chlorine,
hydrochloric acids can form. These
greatly increase the corrosion of metals.
Also, refrigerant oil rapidly absorbs moisture.
Water-formed acids combine with the
refrigerant, forming a closely bonded
mixture of fine globules.
The effect is called sludging and it
greatly reduces the lubricating
ability of the oil.
A vacuum pump removes troublesome moisture by
lowering the pressure within the system and vaporizing
(or boiling off) the moisture, then exhausting it along