Fault Shutdowns; Prolonged Shutdown; Restart After Prolonged Shutdown - York YZ MODEL A Operation And Maintenance Manual

FORM 161.01-OM1
ISSUE DATE: 6/8/2018
For example, an increase in condenser approach tem-
perature (condenser temperature minus leaving con-
denser water temperature) may be an indication of
dirty condenser tubes.

FAULT SHUTDOWNS

The chiller is programmed to shut down on two types
of fault conditions.
• A Cycling fault will allow the chiller to automati-
cally restart when the condition clears.
• A Safety fault requires the cause for the condition
be determined and resolved before restarting.
To restart, all safety faults must be cleared by pressing
the Clear Faults key on the Home screen. The chiller
will restart unless the local Stop key is pressed or the
remote run command has ceased.

PROLONGED SHUTDOWN

If the chiller is to be shut down for an extended period
of time, such as over the winter season, the following
procedure should be followed.
1. Test all system joints for refrigerant leaks with a
leak detector.
• If any leaks are found, they should be re-
paired before allowing the system to stand
for a long period of time.
2. During long idle periods, the tightness of the sys-
tem should be checked periodically.
JOHNSON CONTROLS
SECTION 2 - SYSTEM OPERATING PROCEDURES
3. If freezing temperatures could be encountered
while the system is idle, drain the cooling water
from the cooling tower, condenser and condenser
pump.
4. Drain the chilled water system, chilled water
pump and coils.
5. Open the drains on the evaporator.
6. Open the condenser liquid heads to assure com-
plete drainage.
7. Drain the Variable Speed Drive cooling system.
8. Open the main disconnect switches to the VSD,
condenser water pump and the chilled water
pump.
9. Open the battery disconnect.
10. Ensure the control center is powered off.

RESTART AFTER PROLONGED SHUTDOWN

1. Close all drain valves.
2. Close the battery disconnect switch.
3. Restore power to the control panel so that the UPS
can charge the battery for at least eight hours pri-
or to the planned start-up. The chiller has a start
inhibit setting for if the battery voltage is below
12.8VDC.
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