CDL testing is overlapped by the PDL, VDL and TDL procedures. CDL can only be determined by merging at least two, possibly all three procedures into one. The CDL test requires the highest order of skills and observation techniques. Each suspected component must be isolated and tested in the following manner:
1. A valve or fitting is subjected to high pressure.
2. Spray coat the valve or fitting.
3. Tap the component repeatedly with a rubber mallet to
induce vibration. If no leakage....
4. Gently add heat to the component. If no leakage,
continue on to another component.
This completes a labor intensive CDL test.
CML are measured using a Helium Mass
Spectrometer.
Such super fine leak testing is beyond the normal operations of
the Refrigeration Service Mechanic.
CML is considered an acceptable amount of leakage in our industry
at this point in time
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