7-16. Maintenance of Chemical Stability in Air Conditioning System
General. In order to ensure maximum cleanliness of the air conditioning units internal components which, in turn,
will be reflected by a higher standard of system performance, the following notations must be followed:
(1) Keep all tubing sealed. When it becomes necessary to disconnect a refrigerant line, it should be immediately
sealed with masking tape or plugged depending on the type of connections. It must be remembered that all air contains
moisture and air that enters any part of the system will carry moisture with it and the exposed surfaces will collect moisture
(2) Keep all installation and servicing tools, test gauges, and replacement parts clean.
(3) Use a clean dry oil container for lubrication requirements. When adding oil, the container should be
exceptionally clean and dry. The oil container should be kept capped immediately after use.
(4) Do not keep the air conditioning unit open longer than necessary. When it is necessary to open a system the
servicing tools and other equipment to be utilized must be ready for use so that minimum time is required to perform the
(5) A vacuum pump should be utilized after performing service operations to remove any air that might have
entered the system.
Cleaning Tubing. Wherever refrigerant tubing has been repaired, replaced or otherwise altered the following
procedures are recommended:
(1) A clean, lintless cloth should be drawn through the tubing by means of wire or an electricians tape. This will
remove all the course particles of dirt and dust.
(2) A clean, lintless cloth saturated with carbon tetrachloride should be pulled through the pipe. This procedure is
continued until the saturated cloth is not discolored by dirt.
(3) A clean cloth saturated with compressor oil, squeezed dry, is drawn through the tubing again. This is to remove
any lint. If possible, visual inspection should be made to see that tubing is perfectly clean.
(4) The cleaning job is completed by pulling through a clean dry lintless cloth. The cloth must be lintless as an
accumulation of lint will cause almost as much trouble as scale.