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2. The bearing oil temperature accessed on the Status01 table
should be 120 to 165 F (49 to 74 C). If the bearing
temperature reads more than 180 F (83 C) with the oil
pump running, stop the chiller and determine the cause
of the high temperature. Do not restart the chiller until
corrected.
3. The oil level should be visible anywhere in one of the
two sight glasses. Foaming of the oil is acceptable as
long as the oil pressure and temperature are within
limits.
4. The oil pressure should be between 18 and 30 psid
(124 to 207 kPad), as seen on the LID default screen.
Typically the reading will be 18 to 25 psid (124 to
172 kPad) at initial start-up.
5. The moisture indicator sight glass on the refrigerant
motor cooling line should indicate refrigerant flow and a
dry condition.
6. The condenser pressure and temperature varies with
the chiller design conditions. Typically the pressure
will range between 100 and 210 psig (690 to 1450 kPa)
with a corresponding temperature range of 60 to 105 F
(15 to 41 C). The condenser entering water temperature
should be controlled below the specified design entering
water temperature to save on compressor kilowatt
requirements.
7. Cooler pressure and temperature also will vary with the
design conditions. Typical pressure range will be be-
tween 60 and 80 psig (410 and 550 kPa), with temper-
ature ranging between 34 and 45 F (1 and 8 C).
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. It is accessed on the Equipment Con-
figuration, Config table (Table 2, Example 5).
To Stop the Chiller
1. The occupancy schedule will start and stop the chiller
automatically once the time schedule is set up.
2. By pressing the STOP button for one second, the alarm
light will blink once to confirm that the button has been
pressed, then the compressor will follow the normal shut-
down sequence as described in the Controls section. The
chiller will not restart until the CCN or LOCAL soft-
key is pressed. The chiller is now in the OFF mode.
If the chiller fails to stop, in addition to action that
the PIC will initiate, the operator should close the guide
vanes by overriding the guide vane target to zero to re-
duce chiller load; then by opening the main disconnect.
Do not attempt to stop the chiller by opening an isolating
knife switch. High intensity arcing may occur. Do not re-
start the chiller until the problem is diagnosed and
corrected.
After Limited Shutdown — No special preparations
should be necessary. Follow the regular preliminary checks
and starting procedures.
Extended Shutdown — The refrigerant should be trans-
ferred into the storage vessel (if supplied; see Pumpout and
Refrigerant Transfer Procedures) in order to reduce chiller
pressure and possibility of leaks. Maintain a holding charge
of 5 to 10 lbs (2.27 to 4.5 kg) of refrigerant 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 reser-
voir temperature.
After Extended Shutdown — Be sure that the water
system 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 if necessary.
Check the cooler pressure on the LID default screen, and
compare 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 41.
Recharge the chiller by transferring refrigerant from the
storage tank (if supplied). Follow the Pumpout and Refrig-
erant Transfer Procedures section, page 59. Observe freeze-up
precautions.
Carefully make all regular preliminary and running sys-
tem checks. Perform a Control Test before start-up. If the
compressor oil level appears abnormally high, the oil may
have absorbed refrigerant. Make sure that the oil tempera-
ture is above 140 F (60 C) or cooler refrigerant temperature
plus 50° F (27° C).
Cold Weather Operation — When the entering con-
denser water drops very low, the operator should auto-
matically cycle the cooling tower fans off to keep the
temperature up. Piping may also be arranged to bypass the
cooling tower. The PIC controls have a low limit tower fan
relay (PR3) that can be used to assist in this control.
Manual Guide Vane Operation — Manual opera-
tion of the guide vanes in order to check control operation
or control of the guide vanes in an emergency operation is
possible by overriding the target guide vane position.
Access the Status01 table on the LID and highlight
TARGET GUIDE VANE POSITION. To control the position,
enter a percentage of guide vane opening that is desired.
Zero percent is fully closed, 100% is fully open. To re-
lease the guide vanes to AUTOMATIC mode, press the
RELEASE
softkey.
NOTE: Manual control will increase the guide vanes and
override the pulldown rate during start-up. Motorcurrent above
the electrical demand setting, capacity overrides, and chilled
water below control point will override the manual target
and close the guide vanes. For descriptions of capacity over-
rides and set points, see the Controls section.
Refrigeration Log — A refrigeration log, such as
the one shown in Fig. 33, provides a convenient check-
list for routine inspection and maintenance and provides a
continuous record of chiller performance. It is an aid in
scheduling routine maintenance and in diagnosing chiller
problems.
Keep a record of the chiller pressures, temperatures, and
liquid levels on a sheet similar to that shown. Automatic
recording of PIC data is possible through the use of CCN
devices such as the Data Collection module and a Building
Supervisor. Contact your Carrier representative for more
information.
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