Clean-up Procedure for Refrigeration and Air Conditioning Systems
Lubricant-refrigerant
mixture breakdown causes sludge formation and other corrosive materials that
will hinder the normal operation of compressor valves and control devices in
refrigerant and HVAC systems. Scale, solder particles, dirt, and all types of foreign
substances must be removed to protect the compressor, solenoid valves,
expansion valves, capillary tubes, and other close tolerance parts.
Clean-up
procedure
Follow this
11 step procedure to ensure you have cleaned up your system before proceeding.
1. Diagnosis — Make certain that a motor burnout has
actually occurred by running the proper electrical tests. Determine the
severity of the burnout by analyzing the acid content of the lubricant from the
burned out compressor. This can be done on the job with a TA-1 One Time Acid
Test Kit. Note the color of the lubricant, the smell of the refrigerant, and if
carbon deposits are present in the suction line.
2. Plan the procedure — Consider the following factors:
If the lubricant is not acidic and none of the other indications of severe burn
out are present, then the system can be classified as a “mild burnout” and
cleaned up accordingly. Under these circumstances, it is easier to save the
refrigerant. If a lubricant sample is desired for checking the progress of the
clean-up, then a trap should be installed in the suction line (see Form
40-141). A semi-hermetic compressor can be examined and cleaned by having the
head removed. A heat pump system will frequently require replacing the 4-way
valve, or other special precautions. Systems with a critical charge must have
the charge adjusted due to the added volume in the oversized filter-drier that
is normally installed in the liquid line.
3. Mild Burnout — If the analysis of the lubricant shows no
acidity, then the system can be classified as a mild burnout, and cleaned up
simply by installing an oversized Catch-All Filter-Drier in the liquid line. If
the lubricant is not analyzed, and the other factors indicate some doubt, then
the burnout should be considered severe and cleaned up as described below.
CAUTION—Acid burns can result from touching the sludge in the burned out
compressor. Rubber gloves should be worn when handling contaminated parts.
4. Severe Burnouts —These systems should be cleaned using the
suction line filter-drier method. The refrigerant in the system can be
saved,and must be removed using refrigerant recovery/recycling equipment. The
exact method chosen depends upon the availability of shutoff valves, the amount
of charge, and the other equipment available. See the section on “Saving the
Refrigerant.”
5. Remove the burned out compressor and install the new compressor.
6. Install a Catch-All Suction Line Filter-Drier or RSF shell (selected
from Bulletin 40-10 pages 34 and 35) ahead of the new compressor. The access
valve on the drier permits Catch-All Liquid and Suction line filter driers -
Parker Hannifin Sporlan Divisionthe pressure drop to be checked by installing
gauges on the access valve and at the gauge port on the suction service valve.
For systems without service valves, install a line tap valve downstream of the
Catch-All Filter-Drier for the second connection.
7. Remove the liquid line drier and install an oversized Catch-All (one
size larger than the normal selection size). Check the expansion valve and
other controls to see if cleaning or replacement is required. Install a See•All
Moisture and Liquid Indicator.
8. Evacuate the system according to the manufacturer’s recommendations.
Normally this will include the use of a high vacuum pump and a low vacuum
micron gauge for measuring the vacuum obtained.
9. Recharge the system through the access valve on the suction line
filter-drier. Then start the system according to the manufacturer’s
instructions
10. The use of a Catch-All Filter-Drier installed
permanently in the suction line permits the clean-up of a small system to be
completed with one service call. The pressure drop across the suction line
filter-drier should be measured during the first hour’s operation. If the
pressure drop becomes excessive, then the suction line filter-drier should be
replaced. If the equipment manufacturer’s recommendations are not available,
the following maximum pressure drop levels are suggested. See table below.
11. In 24 hours take a lubricant sample. Observe
the color and test for acidity. If the lubricant is dirty or acidic, replace
the suction line and liquid line filter-driers. In two weeks re-check the color
and acidity of the lubricant to see if another change of filter-driers is
necessary. It may also be desirable to change the lubricant in the compressor.
Before the job is complete, it is essential that the lubricant be clean and
acid-free.
Saving the
refrigerant
The
refrigerant is not damaged by the burnout, and can be reused, provided the
contaminants are removed. When a mild burnout has occurred on a system with
service valves, the refrigerant can be saved by closing the valves and trapping
the refrigerant in the system, while changing the compressor. The system can
then be pumped down with the new compressor to save the refrigerant while
installing an oversized Catch-All Filter-Drier in the liquid line.
If a severe
burnout has occurred, the above procedure might damage the new compressor.
Therefore, it is preferred that the refrigerant be removed from the system for
reclamation. If no service valves are available then the refrigerant must be
removed from the system. Recovery, recycling or reclamation of the refrigerant
must be performed in accordance with EPA regulations. Sporlan recommends the
use of our HH style cores for cleaning up all systems after a hermetic motor
burnout. These cores contain a desiccant mix that is suitable for removing all
types of system contaminants.
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