To Stop The Chiller - Carrier 19XRV Start-Up, Operation And Maintenance Instructions Manual

8. The compressor may operate at full capacity for a short
time after the pulldown ramping has ended, even though
the building load is small. The active electrical demand
setting can be overridden to limit the compressor IkW, or
the pulldown rate can be decreased to avoid a high
demand charge for the short period of high demand
operation. Pulldown rate can be based on load rate or
temperature rate and is accessed on the EQUIPMENT
SERVICE screen, RAMP_DEM table (Table 4,
Example 21).

To Stop the Chiller

1. The occupancy schedule starts and stops the chiller
automatically once the time schedule is configured.
2. By pressing the STOP button for one second, the alarm
light blinks once to confirm the button has been pressed.
The compressor will then follow the normal shutdown
sequence as described in the Shutdown Sequence,
Start-Up/Shutdown/Recycle Sequence section, page 53.
The chiller will not restart until the
softkey is pressed. The chiller is now in the OFF control
mode.
IMPORTANT: Do not attempt to stop the chiller by opening
an isolating knife switch. High intensity arcing may occur.
Do not restart the chiller until the problem is diagnosed
and corrected.
After Limited Shutdown —
should be necessary. Follow the regular preliminary checks and
starting procedures.
Preparation for Extended Shutdown —
erant should be transferred into the pumpout storage tank (if
supplied; see Pumpout and Refrigerant Transfer Procedures) to
reduce chiller pressure and the possibility of leaks. Maintain a
holding charge of 5 to 10 lb (2.27 to 4.5 kg) of refrigerant or
nitrogen to prevent air from leaking into the chiller.
If freezing temperatures are likely to occur in the chiller
area, drain the chilled water, condenser water, and the pumpout
condenser water circuits to avoid freeze-up. Keep the waterbox
drains open.
Leave the oil charge in the chiller with the oil heater and
controls energized to maintain the minimum oil reservoir
temperature.
After Extended Shutdown —
tem drains are closed. It may be advisable to flush the water
circuits to remove any soft rust which may have formed. This
is a good time to brush the tubes and inspect the Schrader
fittings on the waterside flow devices for fouling, if necessary.
Check the cooler pressure on the ICVC default screen and
compare it to the original holding charge that was left in the
chiller. If (after adjusting for ambient temperature changes) any
loss in pressure is indicated, check for refrigerant leaks. See
Check Chiller Tightness section, page 56.
or
CCN LOCAL
No special preparations
The refrig-
Ensure the water sys-
Recharge the chiller by transferring refrigerant from the
pumpout storage tank (if supplied). Follow the Pumpout and
Refrigerant Transfer Procedures section, page 74. Observe
freeze-up precautions.
Carefully make all regular preliminary and running system
checks. Perform a Control Test before start-up. If the compres-
sor oil level appears abnormally high, the oil may have
absorbed refrigerant. Ensure that the oil temperature is above
140 F (60 C) or above the cooler refrigerant temperature plus
50° F (27° C).
Cold Weather Operation —
denser water temperature drops very low, the operator should
automatically cycle the cooling tower fans off to keep the
temperature up. Piping may also be arranged to bypass the
cooling tower. The PIC III controls have a low limit tower fan
output that can be used to assist in this control (terminals 5 and
6 on the TB2 hazardous voltage field wiring terminal strip).
Manual Guide Vane Operation —
manually operate the guide vanes in order to check control
operation or to control the guide vanes in an emergency. Manu-
al operation is possible by overriding the target guide vane
position. Access the COMPRESS screen on the ICVC and
scroll down to highlight TARGET GUIDE VANE POS. To
control the position, use the
softkey to adjust to the percentage of guide vane opening that is
desired. Zero percent is fully closed; 100% is fully open. To
release the guide vanes to automatic control, press the
softkey.
RELEASE
Similarly, the TARGET VFD SPEED can be manually set
in the COMPRESS screen. The target value is still limited to be
between configured VFD MINIMUM SPEED and VFD
MAXIMUM SPEED. Once speed is manually set in this man-
ner, capacity control changes are directed to modulate the
guide vanes.
NOTE: Manual control mode overrides the configured pull-
down ramp rate during start-up and permits the guide vanes to
open at a faster rate. The PIC III controls will close the guide
vanes if the motor current exceeds the ACTIVE DEMAND
LIMIT or capacity override limits. The guide vanes will
also close if the chilled water temperature falls below the
CONTROL POINT. For descriptions of capacity overrides and
set points, see the Controls section.
Refrigeration Log —
Fig. 38) is a convenient checklist for routine inspection and
maintenance and provides a continuous record of chiller
performance. It is also an aid when scheduling routine mainte-
nance and diagnosing chiller problems.
Keep a record of the chiller pressures, temperatures, and liq-
uid levels on a sheet similar to the one in Fig. 38. Automatic
recording of PIC III data is possible by using CCN devices
such as the Data Collection module and a Building Supervisor.
Contact a Carrier representative for more information.
72
When the entering con-
It is possible to
or
INCREASE DECREASE
A refrigeration log (as shown in