Q41. What are the two methods of refrigerant
Q42. Recycling refrigerant reduces contaminants
through what two processes?
MAINTENANCE OF COMPRESSORS
Learning Objective: Recall the inspection points for
open-type compressors and repair procedures for
common problems in open-type refrigeration
Inspection points for open-type compressors and
repair procedures for common problems in open-type
refrigeration compressors are covered in this section.
OPEN TYPES OF COMPRESSORS
Figure 6-61 shows a vertical single-acting
reciprocating compressor. Some of the duties you may
perform in maintaining this and other open-type
compressors are discussed below.
Shaft Bellows Seal
Refrigerant leakage often occurs at the shaft
bellows seal with consequent loss of charge. Install a
test gauge in the line leading from the drum to the
compressor. Attach a refrigerant drum to the suction
end of the shutoff valve outlet port. Apply the proper
amount of pressure, as recommended in the
manufacturer's instructions. Test for leaks with a
halide leak detector around the compressor shaft, seal
gasket, and seal nut. Slowly turn the shaft by hand.
When a leak is located at the seal nut, replace the seal
plate, gasket, and seal assembly; when the leak is at the
gasket, replace the gasket only. Retest the seal after
reassembly. (This procedure is typical for most shaft
seals on reciprocating open-type compressors.)
Obstructions, such as dirt or corrosion, may be
formed under seats of suction or discharge valves. To
locate the source of trouble, proceed as follows:
When the suction side is obstructed, the unit tends
to run continuously or over long periods. Connect the
gauge manifold and start the unit. This pressure gauge
(HI) will not indicate an increase in pressure. The
low-side gauge (LO) will fluctuate and will not
indicate any decrease in pressure. Clean out any
obstructions and recheck again by using the test gauge
Figure 6-61.Vertical single-acting reciprocating compressor.