Maintenance
Renewal parts
For any required Renewal Parts, refer to the
Renewal Parts – Unit (Form 160.75-RP1)
.
Checking system for leaks
Leak testing during operation
The refrigerant side of the system is carefully pressure tested and evacuated at the factory.
After the system has been charged, the system should be carefully leak tested with a R-134a
compatible leak detector to be sure all joints are tight.
If any leaks are indicated, they must be repaired immediately. Usually, leaks can be stopped by
tightening flare nuts or flange bolts. However, for any major repair, the refrigerant charge must be
removed. See
Handling refrigerant for dismantling and repairs
.
Conducting an R-22 pressure test
About this task:
With the R-134a charge removed and all known leaks repaired, the system should be charged with
a small amount of R-22 mixed with dry nitrogen so that a halide torch or electronic leak detector
can be used to detect any leaks too small to be found by the soap test.
To test with R-22, proceed as follows:
1. With no pressure in the system, charge R-22 gas into the system through the charging valve
to a pressure of 2 psig (14 kPa).
2. Build up the system pressure with dry nitrogen to approximately 75 psig to 100 psig (517
kPa to 690 kPa). To be sure that the concentration of refrigerant has reached all part of the
system, slightly open the oil charging valve and test for the presence of refrigerant with a
leak detector.
3. Test around each joint and factory weld. It is important that this test be thoroughly and
carefully done, spending as much time as necessary and using a good leak detector.
4. To check for refrigerant leaks in the evaporator and condenser, open the vents in the
evaporator and condenser heads and test for the presence of refrigerant. If no refrigerant is
present, the tubes and tube sheets may be considered tight. If refrigerant is detected at the
vents, the heads must be removed, the leak located (by means of soap test or leak detector)
and repaired.
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Model YK Style G R-134a or R-513A
