York YMC2 A, Operation And Maintenance

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JOHNSON CONTROLS
15
Section 2 - System operating procedures
Form 160.78-O1
Issue date: 05/19/2021
2
7. Check for any signs of dirty or fouled condenser
tubes. The temperature difference between water
leaving condenser and saturated condensing tem-
perature should not exceed the difference record -
ed for a new unit by more than 4°F (2.2°C).
Weekly
• Check the refrigerant charge. See
Checking the
refrigerant charge during unit shutdown in Sec-
tion 3 - Maintenance .
Monthly
• Leak check the entire chiller.
Semi-annually (or more often as required)
• Check controls.
Annually (more often if necessary)
1. Evaporator and Condenser.
a. Inspect and clean water strainers.
b. Inspect and clean tubes as required.
c. Inspect end sheets.
2. Compressor Drive Motor.
• Meg motor windings.
3. Inspect and service electrical components as nec-
essary.
4. Perform refrigerant analysis.
Need for maintenance or service
If the system is malfunctioning in any manner or the
unit is stopped by one of the safety controls, see the
Operation Analysis Chart shown in Table 3 ( Section 4
- Troubleshooting ). After consulting this chart, if you
are unable to make the correct repairs or adjustments
to start the compressor or the particular issue continues
to hinder the performance of the unit, call the nearest
Johnson Controls District Office. Failure to report con-
stant troubles could damage the unit and increase the
cost of repairs.
Stopping the system
The OptiView™ Control Center can be programmed
to start and stop automatically (maximum - once each
day) whenever required. Refer to the YMC
2
OptiView
TM
Control Center Operation Manual (Form 160.78-O1) .
To stop the chiller, complete the following steps:
1. Push the soft shutdown key on the Home screen
of the OptiView
TM
panel. The compressor will
stop automatically. In the event of an unusual cir-
cumstance requiring immediate stoppage, a safety
stop switch is located on the side of the control
panel. Normal stop eases the driveline to stop and
should always be used instead of the safety stop
during regular operation.
2. Stop the chilled water pump. If the pump is not
wired into the Microcomputer Control Center, it
turns off automatically. The actual water pump
contact operation depends on the selection on the
SETUP screen.
3. Open the switch to the cooling tower fan motors,
if used.
Prolonged shutdown
If the chiller must be shut down for an extended period
of time, for example, over the winter season, complete
the following procedure:
1. Test all system joints for refrigerant leaks with a
leak detector. If any leaks are found, they should
be repaired before allowing the system to stand
for a long period of time.
During long idle periods, the tightness of the sys-
tem should be checked periodically.
2. If freezing temperatures are encountered while
the system is idle, carefully drain the cooling wa-
ter from the cooling tower, condenser, condenser
pump, and the chilled water system-chilled water
pump and coils.
Open the drains on the evaporator and condenser
liquid heads to ensure complete drainage. Drain
the VSD cooling system.
3. If freezing temperatures are encountered for peri-
ods longer than a few days, the refrigerant should
be recovered to containers to prevent leakage
from O-ring joints.
4. On the SETUP Screen, disable the clock. This
conserves the battery.
5. Open the main disconnect switches to the com-
pressor motor, condenser water pump and the
chilled water pump. Open the 115 V circuit to the
Control Center.