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appropriately inhibited glycols, concentrated to provide
adequate protection for the temperature considered.
2.
Use an electric tape heater for the internal piping if unit will
be exposed to freezing temperature.
3.
Ensure that power is available to the chiller at all times, even
during the off-season, so that the pump and evaporator heat-
ers have power. Also make sure that the piping tape heaters
have power.
4.
On units with pump packages, a heater is supplied that will
protect this section from freezing in outdoor-air temperatures
down to –20°F (–29°C), except in case of a power failure.
5.
Evaporator heaters that will protect down to –20°F (–29°C)
can be installed as a factory option. It should be noted that
these heaters will not protect the evaporator from freezing in
the event of a power failure.
PREPARATION FOR WINTER SHUTDOWN
If the unit is not operational during the winter months, at the end
of the cooling season complete the following steps.
CAUTION
Failure to remove power before draining heater-equipped
evaporators and hydronic packages can result in heater tape
and insulation damage.
1.
If the evaporator/pump will not be drained, do not shut off
power during off-season shutdown. If the evaporator/pump is
drained, open the circuit breaker for the heater or shut off
power during off-season shutdown.
2.
Drain water from the system.
3.
Replace drain plug(s) and add sufficient inhibited glycol (or
other suitable inhibited antifreeze) to evaporator, pump, and
piping to prevent freezing of residual water.
4.
At the beginning of the next cooling season, refill evaporator
and add recommended inhibitor.
Step 5 — Make Electrical Connections
WARNING
Electrical shock can cause personal injury and death. Shut off
all power to this equipment during installation. There may be
more than one disconnect switch. Tag all disconnect locations
to alert others not to restore power until work is completed.
POWER SUPPLY
Electrical characteristics of available power supply must agree
with unit nameplate rating. Field wiring size must be within limits
30RC
CONNECTION TYPE
UNIT SIZES
TERMINAL BLOCK
010-060
NON-FUSED
DISCONNECT
LEGEND
AWG
—
American Wire Gage
MCA
—
Minimum Circuit Amps
SCCR
—
Short Circuit Current Rating
Table 19 — Field Wiring Sizes
MCA RANGE
MCA up to 175
MCA 175.1 to 420
All
MCA up to 125
All
MCA 125.1 to 225
All
MCA 225.1 to 400
All
shown in Table 19. See Tables 20-26 for component electrical
data.
IMPORTANT: Operating unit on improper supply voltage or
with excessive phase imbalance constitutes abuse and may
affect Carrier warranty.
POWER WIRING
All power wiring must comply with applicable local and national
codes. Install field-supplied branch circuit fused disconnect per
NEC (National Electric Code) of a type that can be locked OFF or
ON. Disconnect must be within sight from and readily accessible
from unit in compliance with NEC Article 440-14.
General Wiring Notes
1.
The control circuit does NOT require a separate power
source. Control circuit power is obtained by a step-down
transformer from the main three-phase power supply. The
TB5 and TB6 (EMM) terminal strip is provided for field-
wired control devices.
2.
Evaporator and pump heaters (if factory installed) are wired
in the control circuit so they are operable as long as the main
power supply to the unit and heater safety device is ON. A
factory-installed fuse protects them.
3.
Power is at one end only.
4.
All field power enters the unit through a hole located in the
corner post of the unit or the bottom of the control box shelf.
Refer to Fig. 26 for field wiring details. Refer to Fig. 5-11 for
exact location of field power entry. Be sure to seal entering
power wire conduit per NEC requirements.
5.
Maximum field wire sizes allowed by lugs on terminal block/
non-fused disconnect are listed in Table 19.
6.
Terminals for field power supply are suitable for copper con-
ductors. Insulation must be rated 167°F (75°C) minimum.
7.
Units with high short circuit ratings and terminal block option
require that specific fuses be applied to achieve this rating.
Refer to Table 19.
8.
Check that cabling will not be subject to wear, corrosion,
excessive pressure, vibration, sharp edges or any other
adverse environmental effects. The check shall also take into
account the effects of aging or continual vibration from
sources such as compressors or fans.
MAXIMUM NUMBER OF
WIRE SIZE RANGE
WIRES PER PHASE
14 AWG to 2/0 AWG
2 AWG to 600 kcmil
14 AWG to 3/0 AWG
4 AWG to 4/0
2/0 AWG to 500 kcmil
2/0 AWG to 250 kcmil
NOTES:
1. Wiring for main field supply must be rated 75°C. Use copper conductors
only.
2. Units with high SCCR option and terminal block must use approved fuses to
meet high SCCR rating.
36
HIGH SCCR FUSE
TYPE
1
J, T, RK1, RK5, G, CC
1
J, T, RK1, RK5, G, CC
1
—
1
—
1
—
2
—
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