Sterlco 30RA Outdoor Air Cooled Central Chillers 10-60 Tons - Manual (Page 18)

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Step 5 — Make Electrical Connections
POWER SUPPLY — Electrical characteristics of available
power supply must agree with unit nameplate rating. Field wir-
ing size and supply voltage must be within limits shown in
Tables 7 and 8. See Tables 9-11 for component electrical data.
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, U.S.A.) of a type 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. Up
to two terminal blocks are provided for field-wired
control devices.
2. Cooler 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 is ON. A factory-installed
and set overload device protects them.
NOTE: The field-supplied disconnect should never be off
except when unit is being serviced or is to be down for a pro-
longed period, in which case cooler should be drained.
3. Power entry is at one end only.
4. Maximum field wire sizes allowed by lugs on terminal
block/non-fused disconnect are listed in Table 7.
5. Terminals for field power supply are suitable for
copper conductors. Insulation must be rated 167 F (75 C)
minimum.
Table 7 — Recommended Field Wiring Sizes
FIELD CONNECTIONS
Main Power — Bring wires from the fused disconnect switch
through hole in bottom of left front corner post (010-030 sizes)
or through hole in bottom center panel (032-055 sizes) of unit
to bottom of control box and connect to terminals on terminal
block or non-fused disconnect. A field neutral is required for
380/415-3-50 units only. To comply with NEC Article 440-14,
the disconnect must be located within sight from and readily
accessible from unit. Refer to Fig. 18 and 19.
Control Power — Control power is obtained from the main
power supply and does NOT require a separate source. A
toggle switch (marked Emergency On-Off on the unit label
diagram and by the switch) allows the control circuit to be
manually disconnected when necessary. Cooler and pump
heaters (if installed) are in an operable state when this switch is
in the Off position.
Step 6 — Install Accessories
ELECTRICAL — A number of electrical accessories are
available to provide the following optional features (for details,
refer to the Controls, Start-Up, Operation, Service, and
Troubleshooting book):
Energy Management Module (Used for any of the following
types of temperature reset, demand limit and ice features):
• 4 to 20 mA leaving fluid temperature reset (requires
field-supplied 4 to 20 mA generator)
• 4 to 20 mA cooling set point reset (requires field-
supplied 4 to 20 mA generator)
• Discrete inputs for 2-step demand limit (requires field-
supplied dry contacts)
• 4 to 20 mA demand limit (requires field-supplied 4 to
20 mA generator)
• Discrete input for Ice Done switch (requires field-
supplied dry contacts)
Navigator Display — Provides hand-held, mobile capability
using easy to read 4-line display. Keypad function is the same
as the Scrolling Marquee module. Features magnet for ‘hands
free’ service of components.
Low Ambient Operation — If outdoor ambient operating
temperatures below 45 F (7.2 C) for 30RA010-018 units and
32 F (0.0° C) for 30RA022-055 units are expected, refer to sep-
arate installation instructions for low-ambient operation using
accessory Motormaster® V control.
Minimum Load Accessory — If minimum load accessory is
required, refer to unit Price Pages or contact your local Sterling
representative for more details. For installation details, refer to
separate installation instructions supplied with the accessory
package.
Miscellaneous Accessories — For applications requiring spe-
cial accessories, the following packages are available: Coil hail
guard, external vibration, enhanced display, temperature reset,
condenser coil grilles, storage tank and remote cooler. For
installation details, refer to separate installation instructions
supplied with these accessory packages.
ELECTRIC SHOCK HAZARD.
To avoid the possibility of electrical shock,
open and tag all disconnects before installing
this equipment.
IMPORTANT: Operating unit on improper supply voltage
or with excessive phase imbalance constitutes abuse and
may affect Sterling warranty.
CONNECTION
TYPE
MAX WIRE
SIZE
UNIT SIZE AND VOLTAGE
TERMINAL
BLOCK
#2/0 AWG 30RA010-030 (all voltages)
350 kcmil 30RA035-055 (all voltages)
60/100 AMP
NON-FUSED
DISCONNECT
#1 AWG
30RA010-055 (575-3-60)
30RA010-030
(380-3-60, 460-3-60)
30RA010-025 (380/415-3-50)
30RA010-018 (230-3-50, 230-3-60,
208/230-3-60)
250 AMP
NON-FUSED
DISCONNECT
350 kcmil
30RA035-055 (380-3-60, 460-3-60)
30RA032-045 (380/415-3-50)
30RA022-045 (230-3-50)
30RA022-055 (230-3-60, 208/230-
3-60)
AWG — American Wire Gage
IMPORTANT: To ensure power to the heaters, make sure
auxiliary power to unit is always on (except for servicing or
prolonged shutdown).
Proper rotation of condenser fan(s) MUST be verified
before pumps or compressors are started. Consult the Con-
trols, Start-Up and Operation manual provided with this
chiller for correct procedure. Improper pump rotation can
cause permanent damage to pump impeller and housing. If
pump(s) have been removed for trimming, verify that wir-
ing is reconnected in the original manner.