Callout Description Callout Description
A Evaporator vapor service valve D Compressor discharge isolation
valves (2) *
B Condenser drain isolation valve E Condenser vapor service valve (2)
C Liquid drain service valve (2) F Evaporator liquid service valve
Note: * Ensure that both compressor discharge isolation valves are open.
System pressure test
With the refrigerant charge removed and all known leaks repaired, charge the system with a small
amount of refrigerant mixed with dry nitrogen. You can then use an electronic leak detector to
detect any leaks that are too small to be found by the soap test.
WARNING
Take care not to exceed the rated pressure of the unit refrigerant pressure relief valves.
Conducting the gas pressure hold test
1. To monitor the system pressure over time, install a high-quality, high-resolution analog
pressure gauge on one of the shells. Use a pressure gauge that has a resolution of 2 psi (13.8
kPa) increments with a dial face at 3 in. (76 mm) in diameter or greater.
2. Before proceeding, make sure that the unit is at the initial evacuation level of 5 mmHg.
Important: To prevent freezing of any moisture that might be in the system, do not go
below 5 mmHg. See System evacuation for more details.
3. With the system in a vacuum, slowly charge nitrogen vapor only into the system.
4. Slowly build up the system pressure with dry nitrogen to the design working pressure (DWP)
as found on the chiller vessel data plates.
5. Allow the pressure to remain in the chiller based on Figure 58. This chart provides the hold
times for pressure hold testing based on the vessel diameter and length.
YVAM with OptiView Control Center142
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