19XR (PIC II) Hermetic Centrifugal Liquid Chillers 50 Hz - Carrier

6. Valve off the vacuum pump, stop the pump, and record
the instrument reading.
7. After a 2-hour wait, take another instrument reading. If
the reading has not changed, dehydration is complete. If
the reading indicates vacuum loss, repeat Steps 4 and 5.
8. If the reading continues to change after several attempts,
perform a leak test up to the maximum 1103 kPa pressure.
Locate and repair the leak, and repeat dehydration.
1. To vacuum pump
2. Mixture of dry ice and methyl alcohol
3. Moisture condenses on cold surface
4. From system
4.5 - Inspect Wiring
Fig. 26 - Dehydration cold trap
WARNING: Do not check voltage supply without proper
equipment and precautions. Serious injury may result. Follow
power company recommendations.
CAUTION: Do not apply any kind of test voltage, even for a
rotation check, if the chiller is under a dehydration vacuum.
Insulation breakdown and serious damage may result.
1. Examine wiring for conformance to job wiring diagrams
and to all applicable electrical codes.
2. On low-voltage compressors (600 V or less) connect voltmeter
across the power wires to the compressor starter and
measure the voltage. Compare this reading with the voltage
rating on the compressor and starter nameplates.
3. Compare the ampere rating on the starter nameplate with
the compressor nameplate. The overload trip amps must
not be more than 108% of the rated load amps.
4. The starter for a centrifugal compressor motor must contain
the components and terminals required for PIC II refrigeration
control. Check certified drawings.
5. Check the voltage to the following components and compare
to the nameplate values: oil pump contact, pumpout
compressor starter, and control box.
6. Be sure that disconnects have been supplied for the oil
pump, control box, and pumpout unit.
7. Check that all electrical equipment and controls are properly
grounded in accordance with job drawings, certified drawings,
and all applicable electrical codes.
8. Make sure that the customer’s contractor has verified
proper operation of the pumps, cooling tower fans, and
associated auxiliary equipment. This includes ensuring
that motors are properly lubricated and have proper electrical
supply and proper rotation.
9. For field-installed starters only, test the chiller compressor
motor and its power lead insulation resistance with a
500-V insulation tester such as a megohmmeter. (Use a
5000-V tester for motors rated over 600 V.) Factorymounted
starters do not require a megohm test.
a. Open the starter main disconnect switch and follow
lockout/tagout rules.
b. With the tester connected to the motor leads, take 10second
and 60-second megohm readings as follows:
6-Lead Motor -Tie all 6 leads together and test between the
lead group and ground. Next tie leads in pairs, 1 and 4, 2
and 5, and 3 and 6. Test between each pair while grounding
the third pair.
3-Lead Motor - Tie terminals 1, 2, and 3 together and test
between the group and ground.
- Divide the 60-second resistance reading by the 10second
reading. The ratio, or polarization index, must
be one or higher. Both the 10- and 60-second
readings must be at least 50 megohms.
- If the readings on a field-installed starter are unsatisfactory,
repeat the test at the motor with the power
leads disconnected. Satisfactory readings in this second
test indicate the fault is in the power leads.
NOTE: Unit-mounted starters do not have to be megohm
tested.
10. Tighten up all wiring connections to the plugs on the ISM,
8-input, and CCM modules.
11. Ensure that the voltage selector switch inside the control
box is switched to the incoming voltage rating.
12. On chillers with free-standing starters, inspect the control
box to ensure that the contractor has fed the wires into the
bottom of the panel. Wiring into the top of the panel can
cause debris to fall into the contactors. Clean and inspect
the contactors if this has occurred.
4.6 - Carrier Comfort Network Interface (see Fig. 21)
The Carrier Comfort Network (CCN) communication bus
wiring is supplied and installed by the electrical contractor. It
consists of shielded, 3-conductor cable with metallic braiding.
The system elements are connected to the communication bus
in a daisy chain arrangement. The positive pin of each system
element communication connector must be wired to the positive
pins of the system element on either side of it; the negative
pins must be wired to the negative pins; the signal ground pins
must be wired to signal ground pins.
To attach the CCN communication bus wiring, refer to the
certified drawings and wiring diagrams. The wire is inserted
into the CCN communications plug (J1) on the CVC module.
4.7 - Check Starter
CAUTION: BE AWARE that certain automatic start
arrange-ments can engage the starter. Open the disconnect
ahead of the starter in addition to shutting off the chiller or
pump.
Use the instruction and service manual supplied by the starter
manufacturer to verify that the starter has been installed
correctly, to set up and calibrate the starter, and for complete
troubleshooting information.
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