63
Perform a Control Test —
Check the safety controls
status by performing an automated control test. Access the
CONTROL TEST table and select a test to be performed func-
tion (Table 7).
The Automated Control Test checks all outputs and inputs
for function. It will also set the refrigerant type. The compres-
sor must be in the OFF mode to operate the controls test. The
compressor can be put in OFF mode by pressing the STOP
push-button on the CVC. Each test asks the operator to confirm
the operation is occurring and whether or not to continue. If an
error occurs, the operator can try to address the problem as the
test is being done or note the problem and proceed to the next
test.
When the control test is finished or the
softkey is
pressed, the test stops, and the CONTROL TEST menu dis-
plays. If a specific automated test procedure is not completed,
access the particular control test to test the function when
ready. The CONTROL TEST menu is described in the table
below.
NOTE: During any of the tests, an out-of-range reading will have an
asterisk (*) next to the reading and a message will be displayed.
COOLER CONDENSER PRESSURE TRANSDUCER
AND WATERSIDE FLOW DEVICE CALIBRATION —
Calibration can be checked by comparing the pressure read-
ings from the transducer to an accurate refrigeration gage read-
ing. These readings can be viewed or calibrated from the
HEAT_EX screen on the CVC. The transducer can be checked
and calibrated at 2 pressure points. These calibration points are
0 psig (0 kPa) and between 25 and 250 psig (173 and
1724 kPa). To calibrate these transducers:
1. Shut down the compressor, cooler, and condenser
pumps.
NOTE: There should be no flow through the heat
exchangers.
2. Disconnect the transducer in question from its
Schrader fitting for cooler or condenser transducer cal-
ibration. For oil pressure or flow device calibration
keep transducer in place.
NOTE: If the cooler or condenser vessels are at 0 psig
(0 kPa) or are open to atmospheric pressure, the trans-
ducers can be calibrated for zero without removing the
transducer from the vessel.
3. Access the HEAT_EX screen and view the particular
transducer reading (the EVAPORATOR PRESSURE or
CONDENSER PRESSURE parameter on the
HEAT_EX screen). To calibrate oil pressure or water-
side flow device, view the particular reading
(CHILLED WATER DELTA P and CONDENSER
WATER DELTA P on the HEAT_EX screen). It should
read 0 psi (0 kPa). If the reading is not 0 psi (0 kPa),
but within ±5 psi (35 kPa), the value may be set to zero
by pressing the
softkey while the appropri-
ate transducer parameter is highlighted on the CVC
screen. Then press the
softkey. The value will
now go to zero. No high end calibration is necessary
for flow devices.
If the transducer value is not within the calibration
range, the transducer returns to the original reading. If
the pressure is within the allowed range (noted above),
check the voltage ratio of the transducer. To obtain the
voltage ratio, divide the voltage (dc) input from the
transducer by the supply voltage signal (displayed in
CONTROL TEST menu in the CCM PRESSURE
TRANSDUCERS screen) or measure across the posi-
tive (+ red) and negative (– black) leads of the trans-
ducer. For example, the condenser transducer voltage
input is measured at CCM terminals J2-4 and J2-5.
The voltage ratio must be between 0.80 and 0.11 for
the software to allow calibration. Pressurize the trans-
ducer until the ratio is within range. Then attempt cali-
bration again.
4. A high pressure point can also be calibrated between
25 and 250 psig (172.4 and 1723.7 kPa) by attaching a
regulated 250 psig (1724 kPa) pressure (usually from a
nitrogen cylinder). The high pressure point can be cali-
brated by accessing the appropriate transducer parame-
ter on the HEAT_EX screen, highlighting the
parameter, pressing the
softkey, and then
using the
or
softkeys to
adjust the value to the exact pressure on the refrigerant
gage. Press the
softkey to finish the calibra-
tion. Pressures at high altitude locations must be com-
pensated for, so the chiller temperature/pressure
relationship is correct.
The PIC II does not allow calibration if the transducer is too
far out of calibration. In this case, a new transducer must be in-
stalled and re-calibrated.
Check Optional Pumpout System Controls
and Compressor —
Controls include an on/off switch, a
3-amp fuse, the compressor overloads, an internal thermostat, a
compressor contactor, and a refrigerant high pressure cutout.
The high pressure cutout is factory set to open at 161 psig
(1110 kPa) and reset at 130 psig (896 kPa). Ensure the water-
cooled condenser has been connected. Loosen the compressor
holddown bolts to allow free spring travel. Open the compres-
sor suction and discharge the service valves. Ensure oil is visi-
ble in the compressor sight glass. Add oil if necessary.
See the Pumpout and Refrigerant Transfer Procedures and
Optional Pumpout System Maintenance sections, pages 69 and
76, for details on the transfer of refrigerant, oil specifications,
etc.
High Altitude Locations —
Because the chiller is ini-
tially calibrated at sea level, it is necessary to recalibrate the
pressure transducers if the chiller has been moved to a high
altitude location. See the calibration procedure in the Trouble-
shooting Guide section.
CCM Pressure Thermistors
Check of all thermistors.
CCM Pressure Transducers
Check of all transducers.
Pumps
Checks operation of pump
outputs; pumps are activated.
Also tests associated inputs
such as flow or pressure.
Discrete Outputs
Activation of all on/off outputs
individually.
Slide Valve
Check of the slide valve
operation.
Pumpdown/Lockout
Pumpdown prevents the low
refrigerant alarm during evac-
uation so refrigerant can be
removed form the unit. Also
locks the compressor off and
starts the water pumps.
Terminate Lockout
To charge refrigerant and
enable the chiller to run after
pumpdown lockout.
Refrigerant Type
Sets type of refrigerant used:
HFC-22 or HFC-134a.
EXIT
SELECT
ENTER
SELECT
INCREASE
DECREASE
ENTER