Johnson Controls YORK OM Titan, Руководство по эксплуатации

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SECTION 4 - GENERAL OPERATING SEQUENCE
JOHNSON CONTROLS
121
FORM 160.72-O1 (810)
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The chiller may be shutdown normally by momentarily
closing the REMOTE STOP CONTACT or by mov-
ing the Compressor Switch to the STOP position. The
chiller may also be stopped via a safety control deter-
mined by software. In this event it will display and re-
cord the cause of shutdown.
The following safeties are HARDWIRED to stop the
chiller regardless of the condition of the Output con-
trolling the motor starter:
Emergency Stop-Pull to Stop Push button •
Compressor Discharge High Pressure Cutout •
Chilled Water Low Differential Pressure Cutout •
Condenser Water Low Differential Pressure Cut- •
out
All Compressor Motor Starter Safeties
•
Compressor Oil Low Differential Pressure Cutout •
On any shutdown, the sequence is as follows:
The Vibration Monitor Trip Bypass contact is 1.
closed to prevent nuisance alarms.
The compressor motor start relay is de-energized
2.
to open its contact and de-energize the motor
starter control circuit.
Two “dump” solenoid valves are installed in the
3.
main air supply to the pre-rotation vanes and the
hot gas valve to exhaust supply air from the actua-
tors. The exhaust of the supply air will cause the
compressor pre-rotation vanes to close and the hot
gas valve to open to minimize back flow of gas
through the compressor.
The interstage valve will be closed by software.
4.
The hot gas valve is opened and the interstage
valve is closed to equalize the condenser pressure
with the evaporator. These actions are taken to re-
duce backspin of the compressor on shutdown. If
the chiller is shutdown by a stop command, an or-
derly shutdown occurs attempting to open the re-
cycle gas valve and close the vanes and interstage
valve before the stop sequence is completed.
The oil separator heaters and condenser gas sup-
5.
ply to jet pump oil eductor solenoid valve are de-
energized.
The water low differential pressure, and low oil
6.
pressure safety logic is inactivated to prevent nui-
sance alarms.
The anti-recycle timer is activated at this time.
7.
The anti-recycle (cool down) time depends on the
number of previous starts attempted as described
under anti-recycle operation at the end of this sec-
tion.
During this time, further restarts of the motor are
8.
prevented.
The compressor sump vent solenoid is de-ener-
9.
gized to close the sump vent line ball valve,
The interstage liquid injection and auxiliary cool-
10.
ing water solenoid valves are de-energized.
The compressor and gear auxiliary oil pump mo-
11.
tors are started and the post-lube timing logic is
enabled.
The chilled water flow may be shut off at this time.
If the shutdown is caused by Low Refrig-
erant Pressure, this could be an indication
of a major refrigerant leak. In this event,
the chilled water flow must be maintained
to prevent freeze-up and damage to the
tubes.
Five seconds after the shutdown, the compressor oil
heaters are enabled for control by the temperature
setpoint in software.
Approximately 120 Seconds the shutdown, the drive
components will have coasted to a stop and the auxil-
iary oil pumps will be turned off.
4