Factory-Option Thru-Base Connections (Elec- Trical Connections); Field Control Wiring - Bryant 549J Series Installation Instructions Manual

FACTORY-OPTION THRU-BASE CONNECTIONS (ELEC-
TRICAL CONNECTIONS)
This service connection kit consists of a
connector and a 3 / -in. electrical bulkhead connector, all factory-
4
installed in the embossed (raised) section of the unit basepan in the
condenser section. The 3 / -in. bulkhead connector enables the low-
4
voltage control wires to pass through the basepan. The
trical bulkhead connector allows the high-voltage power wires to
pass through the basepan. See Fig. 25.
Check tightness of connector lock nuts before connecting electri-
cal 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 appro-
priate conduits. Connect the power conduit to the internal discon-
nect (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 CONNECTIONS (ELEC-
TRICAL CONNECTIONS)
1. Install power wiring conduit through side panel openings.
Install conduit between disconnect and control box.
2. Install power lines to terminal connections as shown in
Fig. 20 on page 14.
Voltage to compressor terminals during operation must be within
voltage range indicated on unit nameplate. On 3-phase units, volt-
ages between phases must be balanced within 2% and the current
within 10%. Use the formula shown in the example below to de-
termine 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 invalidate any applicable warranty.
1 / -in. electrical bulkhead
2
1 / -in. elec-
2
LOW VOLTAGE
CONDUIT
CONNECTOR
HIGH VOLTAGE
CONDUIT
CONNECTOR
Example: Supply voltage is 230-3-60
A B C
AB = 224 v
BC = 231 v
AC = 226 v
MOTOR
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 = 100 x
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
immediately.

FIELD CONTROL WIRING

The 549J unit requires an external temperature control device. This
device can be a thermostat (field-supplied) or the RTU Open Con-
troller for Building Management Systems using non-CCN protocols
(RTU Open is available as a factory-installed option only).
THERMOSTAT
Select a Bryant-approved accessory 2-stage Cooling/Heating ther-
mostat. The 549J models do not require a thermostat with an O
function to control the reversing valve operation. If using an elec-
tronic thermostat, configure it for "non-heat pump" operation. In-
stall 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 accordance with the ther-
mostat 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 thermostat does not require a
24-v source (no "C" connection required), use a thermostat cable
or equivalent with minimum of six leads. See Fig. 26. Check the
thermostat installation instructions for additional features which
might require 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) minimum]. For 50 to 75
ft. (15 to 23 m), use no. 16 AWG insulated wire [35°C (95°F) min-
imum]. For over 75 ft. (23 m), use no. 14 AWG insulated wire
[35°C (95°F) minimum]. Wire sizes larger than no. 18 AWG can-
not be directly connected to the thermostat and will require a junc-
tion box and splice at the thermostat.
16
(224 + 231 +
681
226)
= =
3 3
4
= 1.78%
227
227