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FACTORY-OPTION
THRU-BASE
(ELECTRICAL CONNECTIONS)
This service connection kit consists of a
bulkhead connector and a
3
/
tor, all factory-installed in the embossed (raised) section of
the unit basepan in the condenser section. The
head connector enables the low-voltage control wires to
pass through the basepan. The
connector allows the high-voltage power wires to pass
through the basepan. See Fig. 25.
Check tightness of connector lock nuts before connecting
electrical conduits.
Field-supplied and field-installed liquid tight conduit
connectors and conduit may be attached to the connectors
on the basepan. Pull correctly rated high voltage and low
voltage through appropriate conduits. Connect the power
conduit to the internal disconnect (if unit is so equipped) or
to the external disconnect (through unit side panel). A hole
must be field cut in the main control box bottom on the left
side so the 24-v control connections can be made. Connect
the control power conduit to the unit control box at this
hole.
Fig. 25 — Thru-Base Connection Fittings
UNITS
WITHOUT
THRU-BASE
(ELECTRICAL CONNECTIONS)
1.
Install power wiring conduit through side panel open-
ings. Install conduit between disconnect and control
box.
2.
Install power lines to terminal connections as shown in
Fig. 18 on page 13.
Voltage to compressor terminals during operation must
be within voltage range indicated on unit nameplate. On 3-
phase units, voltages between phases must be balanced
within 2% and the current within 10%. Use the formula
shown in the example below to determine the percent of
voltage imbalance. Operation on improper line voltage or
excessive phase imbalance constitutes abuse and may cause
damage to electrical components. Such operation would in-
validate any applicable Bryant warranty.
CONNECTIONS
1
/
-in. electrical
2
-in. electrical bulkhead connec-
4
3
/
-in. bulk-
4
1
/
-in. electrical bulkhead
2
LOW VOLTAGE
CONDUIT
CONNECTOR
HIGH VOLTAGE
CONDUIT
CONNECTOR
CONNECTIONS
Example: Supply voltage is 230-3-60
A
B
C
AB = 224 v
BC = 231 v
AC = 226 v
MOTOR
(224 + 231 + 226)
Average Voltage
=
Determine maximum deviation from average voltage.
(AB) 227-224 = 3 v
(BC) 231-227 = 4 v
(AC) 227-226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
% Voltage Imbalance = 100x
This amount of phase imbalance is satisfactory as it is below
the maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more
than 2%, contact your local electric utility company immedi-
ately.
FIELD CONTROL WIRING
The 551J unit requires an external temperature control
device. This device can be a thermostat emulation device
provided as part of a third-party Building Management Sys-
tem or the RTU Open Controller for Building Management
Systems (RTU Open is available as a factory-installed op-
tion only).
THERMOSTAT
Select a Bryant-approved accessory thermostat. When
electric heat is installed in the 551J unit, the thermostat must
be capable of energizing the G terminal (to energize the In-
door Fan Contactor) whenever there is a space call for heat
(energizing the W1 terminal). The accessory thermostats
listed on the unit price pages can provide this signal but they
are not configured to enable this signal as shipped.
Install the accessory thermostat according to installation
instructions included with the accessory.
Locate the thermostat accessory on a solid wall in the
conditioned space to sense average temperature in accor-
dance with the thermostat installation instructions.
If the thermostat contains a logic circuit requiring 24-v
power, use a thermostat cable or equivalent single leads of
different colors with minimum of seven leads. If the ther-
mostat does not require a 24-v source (no "C" connection
required), use a thermostat cable or equivalent with mini-
mum of six leads. See Fig. 26. Check the thermostat instal-
lation instructions for additional features which might re-
quire additional conductors in the cable.
For wire runs up to 50 ft. (15 m), use no. 18 AWG
(American Wire Gage) insulated wire [35°C (95°F) mini-
mum]. For 50 to 75 ft. (15 to 23 m), use no. 16 AWG insu-
lated wire [35°C (95°F) minimum]. For over 75 ft. (23 m),
use no. 14 AWG insulated wire [35°C (95°F) minimum].
Wire sizes larger than no. 18 AWG cannot be directly con-
nected to the thermostat and will require a junction box and
splice at the thermostat.
16
681
=
=
227
3
3
4
=
1.78%
227
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