TESTING FOR
VIBRATION DEPENDENT LEAKAGE (VDL)
Leaks that only occur while the unit is in
operation are some of the rarest leaks of all. |
Studies have shown that certain components and piping on refrigeration units will develop vibration leaks.
1. The high pressure gas used during PDL should be
dumped and the unit recharged with the proper refrigerant.
2. Place the unit in operation and spray coat the
following areas while viewing for Bubble/Foam formation:
 | All compressor bolts and gasket edges |
| Suction line connection at compressor |
| Discharge line connection at compressor |
| Discharge line connection at condenser |
| Vibration eliminators |
| Any joint or fitting on unsupported pipe runs |
| Expansion and solenoid valves |
| Cap tube connections |
| Sight glass |
This completes VDL Testing.
TESTING FOR
TEMPERATURE DEPENDENT LEAKS (TDL)
All mechanical
connections expand when heated. The connections on a
refrigeration system |
1. Place the unit in operation and raise
the operating temperature by partially blocking the condenser air
intake.
2. Spray coat all metal connections, one at a time, and
observe for leakage. Re-wet any extremely hot surface with water
to keep the fluid from evaporating too quickly.
3. When testing Evaporator components, you may induce heat
by placing the unit into defrost. Page 10
