Check The Running System; To Stop The Chiller; After Limited Shutdown; Preparation For Extended Shutdown - Carrier AquaEdge 19DV series Start-Up, Operation And Maintenance Instructions Manual
Two-stage back-to-back centrifugal liquid chillers
with pic5 controls and hfo r-1233zd(e)
50/60 hz
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Also See for AquaEdge 19DV series:
- Installation, operation and maintenance instructions (116 pages) ,
- Operation and troubleshooting (92 pages) ,
- Start-up, operation and maintenance instructions manual (88 pages)
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After the compres-
Check the Running System —
sor starts, the operator should monitor the display 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 Tempera-
tures can be accessed from the Temperatures menu. If
the bearing 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 Transmission Status screen. If not an alert will be
generated. Typically the reading will be slightly lower at
initial start-up. There will be an alarm if compressor is
ON and the bearing pressure drop is less than 10 psid for
10 seconds.
5. The moisture indicator sight glass on the refrigerant mo-
tor cooling line should indicate single phase refrigerant
flow and a dry condition.
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
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 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 pulldown rate can be decreased to avoid a high
demand charge for the short period of high demand oper-
ation. Pulldown rate can be based on load rate or tempera-
ture rate and is viewed at MAINTENANCE MENU
CAPACITY CONTROLS RAMP_DEM (Ramping
Demand Limit Value). Configuration done in General
Config and rate 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.
The occupancy schedule starts
To Stop the Chiller —
and stops the chiller automatically once the time schedule is
configured.
The unit can be stopped manually using the HMI by press-
ing the green Start/Stop icon
. The Unit Start/Stop screen is
displayed. Press Confirm Stop. The compressor will then fol-
low the normal shutdown sequence as described in the Start-
Up/Shutdown/Recycle Sequence section on page 12. 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.
No special preparations
After Limited Shutdown —
should be necessary. Follow the regular preliminary checks and
starting procedures.
If freezing
Preparation for Extended Shutdown —
temperatures are likely to occur in the chiller area, drain the
chilled water, condenser water, and the pumpout condenser wa-
ter circuits to avoid freeze-up. Keep the waterbox drains open.
Ensure that chiller is powered up so purge can automatically
remove non-condensables from the low pressure chiller system
during the shutdown. It is recommended not to store the refrig-
erant in the unit if below freezing temperatures are anticipated
or if the extended shutdown extends past a normal seasonal
shutdown. In that case both refrigerant and water side should
be purged with positive pressure of dry nitrogen.
Ensure the water sys-
After Extended Shutdown —
tem 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 cooler 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
refrigerant from the pumpout storage tank (if supplied). Follow
the Pumpout and Refrigerant Transfer Procedures section on
page 38. Observe freeze-up precautions.
Carefully make all regular preliminary and running system
checks.
When the entering con-
Cold Weather Operation —
denser water temperature drops very low, the operator
should automatically cycle the cooling tower fans off to
keep the temperature up and tower bypass piping may be re-
quired. Economizer bypass option may be required for units
operating at low lift.
IMPORTANT: A field-supplied water temperature con-
trol system for condenser water should be installed.
The system should be able to maintain the leaving con-
denser water temperature at design conditions.
It is possible to
Manual Guide Vane Operation —
manually operate the guide vanes in order to check control
operation or to control the guide vanes in an emergency.
Manual operation is possible by overriding the target guide
vane position.
NOTE: Manual control overrides the configured pulldown
rate during start-up and permits the guide vanes to open at a
faster rate. Motor current above the electrical demand set-
ting, capacity overrides, and chilled water temperature
below the control point override the manual target and close
the guide vanes. For descriptions of capacity overrides and
set points, see the 19DV with PIC5 Controls Operation and
Troubleshooting guide.
A refrigeration log (as shown in
Refrigeration Log —
Fig. 36), 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
maintenance and diagnosing chiller problems.
Keep a record of the chiller pressures, temperatures, and
liquid levels on a sheet similar to the one in Fig. 36. Auto-
matic recording of data is possible by using CCN devices
such as the Data Collection module and a Building Supervi-
sor. Contact a Carrier representative for more information.
Page 36
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Table of Contents
Troubleshooting
