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To avoid unnecessary surge prevention, add about 10 psid
(70 kPad) to
D
P2 from these conditions:
D
T2 = 10° F (5.5° C)
D
P2 = 93 psid (642 kPad)
Calculate Minimum Load — To calculate minimum load con-
ditions, estimate the temperature difference that the cooler
will have at 20% load, then estimate what the suction and
condensing temperatures will be at this point. Use the proper
saturated pressure and temperature for the particular refrig-
erant used.
Suction Temperature:
43 F (6.1 C) = 38 psig (262 kPa) saturated
refrigerant pressure (HFC-134a)
Condensing Temperature:
70 F (21.1 C) = 71 psig (490 kPa) saturated
refrigerant pressure (HFC-134a)
Minimum Load
D
T1 (at 20% Load):
2° F (1.1° C)
Minimum Load
D
P1:
71 – 38 = 33 psid (490 – 262 = 228 kPad)
Again, to avoid unnecessary surge prevention, add 20 psid
(140 kPad) at
D
P1 from these conditions:
D
T1 = 2° F (1.1° C)
D
P1 = 53 psid (368 kPad)
If surge prevention occurs too soon or too late:
LOAD
SURGE PREVENTION
SURGE PREVENTION
OCCURS TOO SOON
OCCURS TOO LATE
At low loads
(
,
50%)
Increase P1 by
10 psid (70 kPad)
Decrease P1 by
10 psid (70 kPad)
At high loads
(
.
50%)
Increase P2 by
10 psid (70 kPad)
Decrease P2 by
10 psid (70 kPad)
MODIFY EQUIPMENT CONFIGURATION IF NECES-
SARY — The Equipment Configuration table has tables to
select and view or modify. Carrier’s certified drawings will
have the configuration values required for the jobsite. Modify
these tables only if requested.
Config Table Modifications — Change the values in this table
per job data. See certified drawings for values. Modifica-
tions include:
• chilled water reset
• entering chilled water control (Enable/Disable)
• 4-20 mA demand limit
• auto restart option (Enable/Disable)
• remote contact option (Enable/Disable)
Owner-Modified CCN Tables— The following tables are de-
scribed for reference only.
Occdef Table Modifications — The Occdef tables contain
the Local and CCN time schedules, which can be modified
here, or in the Schedule screen as described previously.
Holidef Table Modifications — The Holidef tables configure
the days of the year that holidays are in effect. See Holiday
Scheduling in the Controls section for more details.
Brodefs Table Modifications — The Brodefs table defines
the outside-air temperature sensor and humidity sensor if one
is to be installed. It will define the start and end of daylight
savings time. Enter the dates for the start and end of daylight
savings if required for the location. Brodefs also will acti-
vate the Broadcast function which enables the holiday pe-
riods that are defined on the LID.
Other Tables — The Alarmdef, Cons-def, and Runt-def con-
tain tables for use with a CCN system. See the applicable
CCN manual for more information on these tables.
These tables can only be defined through a CCN Building
Supervisor.
CHECK VOLTAGE SUPPLY — Access the Status 01 screen
and read the LINE VOLTAGE: ACTUAL value. This reading
should be equal to the incoming power to the starter. Use a
voltmeter to check incoming power at the starter power leads.
If the readings are not equal, an adjustment can be made by
selecting the LINE VOLTAGE: ACTUAL point and then in-
creasing or decreasing the value so that the value appearing
on the LID is calibrated to the incoming power voltage
reading. Voltage can be calibrated only to between 90 and
100 percent of rated line voltage.
PERFORM AN AUTOMATED CONTROL TEST — Check
the safety controls status by performing an automated con-
trols test. Access the Control Test table and select the Au-
tomated Tests function (Table 7).
The Automated Control Test will check all outputs and
inputs for function. It will also set the refrigerant type. The
compressor must be in the OFF mode in order to operate the
controls test and the 24-v input to the SMM must be in range
(per line voltage percent on Status01 table). The OFF mode
is caused by pressing the STOP pushbutton on the LID. Each
test will ask the operator to confirm that the operation is oc-
curring, and whether or not to continue. If an error occurs,
the operator has the choice to try to address the problem as
the test is being done, or to note the problem and proceed to
the next test.
NOTE: If during the Control Test the guide vanes do not
open, check to see that the low pressure alarm is not active.
(This will cause the guide vanes to close.)
NOTE: The oil pump test will not energize energize the oil
pump if cooler pressure is below –5 psig (–35 kPa).
When the test is finished, or the EXIT softkey is pressed,
the test will be stopped and the Control Test menu will be
displayed. If a specific automated test procedure is not
completed, access the particular control test to test the func-
tion when ready. The Control Test menu is described as
follows.
Automated Tests
As described above, a complete
control test.
PSIO Thermistors
Check of all PSIO
thermistors only.
Options Thermistors
Check of all options
boards thermistors.
Transducers
Check of all transducers.
Guide Vane Actuator
Check of the guide vane
operation.
Pumps
Check operation of pump outputs,
either all pumps can be
activated, or individual pumps.
The test will also test
the associated input such as
flow or pressure.
Discrete Outputs
Activation of all on/off
outputs or individually.
Pumpdown/Lockout
Pumpdown prevents the low
refrigerant alarm during
evacuation so refrigerant
can be removed from the unit;
locks the compressor off; and
starts the water pumps.
Terminate Lockout
To charge refrigerant and enable
the chiller to run after pumpdown
lockout.
56
Содержание 17
Страница 13: ...Fig 6 Open Drive 17 Series Lubrication Cycle 13 ...
Страница 15: ...Fig 7 17EX Controls and Sensor Locations 15 ...
Страница 16: ...Fig 7 17EX Controls and Sensor Locations cont 16 ...
Страница 17: ...Fig 7 17EX Controls and Sensor Locations cont 17 ...
Страница 19: ...Fig 8 19EX Controls and Sensor Locations cont 19 ...
Страница 23: ...Fig 16 17 19EX LID Menu Structure 23 ...
Страница 24: ...Fig 17 17 19EX Service Menu Structure 24 ...
Страница 50: ...Fig 28 17 19EX Leak Test Procedures 50 ...