Some of the contaminants most frequently found in refrigeration systems are moisture, copper oxide, dirt, flux, and flaked or powdered aluminium. While the filter-drier will usually trap these materials, this is not always the case.
Moisture and water in a system can lead to further contamination due to formation of rust, corrosion, refrigerate decomposition, oil slugging or general deterioration. By coupling each of these failure components with the resultant damage which can occur with their presence, further areas of failure become obvious.
Excessive heat from friction, copper plating, and unnecessary wear of precision bearing surfaces all could be connected to this contaminant. In addition, ice formed (usually only in R-12 systems) in the expansion valve will restrict refrigerant flow or stop it completely.
One way to detect moisture in a system is with the ~J~-~, liquid Line indicators: sufficient time should be allow the indicator to reach a point of equilibrium and to indicate the proper color. It should be located ahead of the expansion valve and any driers (if present).
In an installation that has been properly installed and dehydrated there is virtually no way that moisture should be an initial prob1em in any reciprocating system. If a leak is present in a chiller so that water enters a refrigeration system, the resultant refrigerant leak would be apparent long before the moisture should be a problem.