Operating Instructions; Operator Duties; Prepare The Chiller For Start-Up; To Start The Chiller - Carrier AquaEdge 19DV Series Start-Up, Operation And Maintenance Instructions Manual

OPERATING INSTRUCTIONS

Operator Duties

1. Become familiar with the chiller and related equipment
before operating the chiller.
2. Prepare the system for start-up, start and stop the chiller,
and place the system in a shutdown condition.
3. Maintain a log of operating conditions and document any
abnormal readings.
4. Inspect the equipment, make routine adjustments, and per-
form a Control Test. Maintain the proper refrigerant levels.
5. Protect the system from damage during shutdown periods.
6. Maintain the set point, time schedules, and other PIC
functions.

Prepare the Chiller for Start-Up

Follow the steps described in the Initial Start-Up section, page 33.

To Start the Chiller

1. Start the water pumps, if they are not automatic.
2. Press the Start/Stop icon on the HMI home screen to start
the system. If the chiller is in the OCCUPIED mode and
the start timers have expired, the start sequence will start.
Follow the procedure described in the Start-Up/Shutdown/
Recycle Sequence section, page 13.

Check the Running System

After the compressor starts, the operator should monitor the dis-
play and observe the parameters for normal operating conditions:
1. The normal bearing temperature should be about 95°F
(35°C). Alert will initiate at 104°F (40°C) and Alarm will
be initiated at 122°F (50°C).
2. The First Stage and Second Stage Bearing Temperatures
can be accessed from the Temperatures menu. If the bear-
ing temperature is high or in Alarm/Alert state with the
refrigerant pump running, stop the chiller and determine
the cause of the high temperature. Do not restart the
chiller until corrected.
3. The liquid level sensor on the condenser float chamber
should indicate Closed in the INPUT menu.
4. The bearing pressure drop should exceed 13 psid (90 kPa)
when the compressor is ON, as seen on the HMI Transmis-
sion Status screen. If not, an alert will be generated. Typi-
cally the reading will be slightly lower at initial start-up.
There will be an alarm if compressor is ON and the bear-
ing pressure drop is less than 10 psid for 10 seconds.
5. The moisture indicator sight glass on the refrigerant motor
cooling line should indicate single phase refrigerant flow
and a dry condition; i.e., solid liquid with no turbulent
bubbles.
6. The condenser pressure and temperature varies with the
chiller design conditions. Typically the pressure will range
from –1.5 to 17.5 psig (–10.3 to 120.6 kPa). with a corre-
sponding temperature range of 60 to 105°F (15 to 41°C).
The condenser entering water temperature should be con-
trolled below the specified design entering water tempera-
ture to save on compressor kilowatt requirements.
7. Evaporator pressure and temperature also will vary with
the design conditions. Typical pressure range will be
between –7.7 to –5.0 psig (–50.8 kPa to –35 kPa), with
temperature ranging between 34 and 45°F (1.1 and 7.2°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 kW, or the pull-
down 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
viewed at Maintenance Menu
RAMP_DEM (Ramping Demand Limit Value). Configura-
tion is done in General Config and rate is done in Service
Parameters.
9. High and low float chambers each provide two sight glasses
for looking into the float chamber to confirm proper float
operation. Note that the sight glasses on the float covers are
used to diagnose a float operation failure of fully closed,
stuck in one position, or fully open. The sight glasses are not
used to identify correct refrigerant charge.

To Stop the Chiller

The occupancy schedule starts and stops the chiller automati-
cally once the time schedule is configured.
The unit can be stopped manually using the HMI by pressing
the green Start/Stop icon
played. Press Confirm Stop. The compressor will then follow
the normal shutdown sequence as described in the Start-Up/
Shutdown/Recycle Sequence section on page 13. 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.
If the chiller is stopped by an alarm condition, do not restart
the chiller until the problem is diagnosed and corrected.

After Limited Shutdown

No special preparations should be necessary. Follow the regu-
lar preliminary checks and starting procedures.
PREPARATION FOR EXTENDED SHUTDOWN
If freezing temperatures are likely to occur in the chiller area,
drain the chilled water, condenser water, and pumpout con-
denser water circuits to avoid freeze-up. Keep the waterbox
drains open. Ensure that chiller is powered up so purge can au-
tomatically remove non-condensables from the low pressure
chiller system during the shutdown. It is recommended not to
store the refrigerant in the unit if below-freezing temperatures
are anticipated or if the extended shutdown extends past a nor-
mal seasonal shutdown. In that case both refrigerant and water
side should be purged with positive pressure of dry nitrogen.

After Extended Shutdown

Ensure the water system drains are closed. It may be advisable
to flush the water circuits to remove any soft rust that 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.
Match the actual to the recorded nitrogen pressure prior to the
extended shutdown to determine if a leak is present. Check the
evaporator pressure on the HMI panel and compare it to the
original holding charge that was left in the chiller. If, after ad-
justing for ambient pressure changes, any change in pressure is
indicated, check for refrigerant leaks. See Check Chiller Tight-
ness section, page 15.
If charge was removed, recharge the chiller by transferring re-
frigerant from the pumpout storage tank (if supplied). Follow
the Pumpout and Refrigerant Transfer Procedures section on
page 39. Observe freeze-up precautions.
Carefully make all regular preliminary and running system
checks.
36
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Capacity Controls
. The Unit Start/Stop screen is dis-
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