Figure 147 - Service Connections; Figure 148 - Service Connection View Showing Evaporator Inlet - York YCIV0157 Installation Operation & Maintenance

Section 9 - Maintenance
Ensure that all the valves in the system
including all EEVs, manual valves, and
ball valves are 100% open, when any
procedures - leak check, evacuation, or
refrigerant handling service - are per-
formed on the chiller system as a whole.
Use these service valves for all vapor and charging
connection processes. This includes evacuation, vacu-
um gauge connection, vapor, and liquid charging.

Figure 147 - Service connections

Figure 148 - Service connection view showing
evaporator inlet
Callout Component
A Compressor discharge line isolation ball valve
B Condenser drain liquid line angle service valve
C Evaporator Liquid Line service valve
D Suction line isolation ball valve (Optional)
Suction service valve also optional (not
shown)
306
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.
Care must be taken 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 service valves. Use a pressure
gauge that has a resolution of 2 psi increments
with a dial face at 3 in. in diameter or greater.
2. Ensure all the system valves including manual
valves and EEVs are 100% open. Make sure that
all valves to the atmosphere are closed with flare
caps in place, if applicable.
3. Before proceeding, make sure that the unit is at
the initial evacuation level of 5 mmHg.
To prevent freezing of any moisture that
might be in the system, do not go below
5 mmHg. See System evacuation on page
309 for more details.
4. With the system in a vacuum, slowly charge nitro-
gen vapor only into the system.
5. Slowly build up the system pressure with dry ni-
trogen to the design working pressure (DWP) as
found on the chiller vessel data plates.
6. Allow the pressure to remain in the chiller based
on Figure 149 on page 307. This chart provides
the hold times for pressure hold testing based on
the vessel diameter and length.
What to do next:
• For a unit with no loss of pressure, proceed to unit
evacuation.
Form 201.23-NM2
Issue date: 12/19/2023
Johnson Controls