Bryant Preferred 549J 04, Installation Instructions Manual

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FIELD CONTROL WIRING
The 549J unit requires an external temperature control device.
This device can be a thermostat (field-supplied) or the RTU
Open Controller for Building Management Systems (RTU
Open is available as a factory-installed option only).
THERMOSTAT
Select a Bryant-approved accessory 2-stage Cooling/Heating
thermostat. The 549J models do not require a thermostat with
an O function to control the reversing valve operation. If using
an electronic thermostat, configure it for “non-heat pump” op-
eration. Install the accessory thermostat according to installa-
tion instructions included with the accessory.
Locate the thermostat accessory on a solid wall in the condi-
tioned space to sense average temperature in accordance 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 thermostat does not
require a 24-v source (no “C” connection required), use a ther-
mostat cable or equivalent with minimum of six leads. See
Fig. 31. Check the thermostat installation instructions for addi-
tional 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) minimum]. For over 75 ft. (23 m), use no. 14 AWG in-
sulated wire [35°C (95°F) minimum]. Wire sizes larger than
no. 18 AWG cannot be directly connected to the thermostat and
will require a junction box and splice at the thermostat.
Fig. 31 — Typical Low-Voltage Control Connections
Thermostat Wiring, Units Without Thru-Base Connection Kit
Pass the thermostat control wires through the hole provided in
the corner post; then feed the wires through the raceway built
into the corner post to the control box. Pull the wires over to
the terminal strip on the upper-left corner of the Controls Con-
nection Board. See Fig. 32.
NOTE: If thru-the-bottom connections accessory is used, refer to
the accessory installation instructions for information on routing
power and control wiring.
Fig. 32 — Field Control Wiring Raceway
HEAT ANTICIPATOR SETTINGS
Set heat anticipator settings at 0.14 amp for the first stage and
0.14 amp for second-stage heating, when available.
COMMERCIAL DEFROST CONTROL
The Commercial Defrost Control Board (DFB) coordinates
thermostat demands for supply fan control, 1 or 2 stage cool-
ing, 2 stage heating, emergency heating and defrost control
with unit operating sequences. The DFB also provides an in-
door fan off delay feature (user selectable). See Fig. 33 for
board arrangement.
Fig. 33 — Defrost Control Board Arrangement
The DFB is located in the 549J unit’s main control box (see
Fig. 34). All connections are factory-made through harnesses
to the unit’s CTB, to IFC (belt-drive motor) or to ECM (direct-
drive motor), reversing valve solenoids and to defrost thermo-
stats. Refer to Table 3 for details of DFB Inputs and Outputs.
Reversing valve control
The DFB has two outputs for unit reversing valve control. Op-
eration of the reversing valves is based on internal logic; this
application does not use an “O” or “B” signal to determine re-
X
C
G
W2
R
C
W2
G
W1
O/B/Y2
Y2
W1
R
Y1 Y1
Typic a l
Thermo s t a t
Connection s
T
H
E
R
M
O
S
T
A
T
(Note 1)
(Note 2)
1. Typic a l m u lti-f u nction m a rking. Follow m a n u f a ct u rer’ s config u r a tion
in s tr u ction s to s elect Y2. Do not config u re for O o u tp u t.
2. W2 connection not req u ired on u nit s witho u t electric he a ting.
Field Wiring
Centr a l
Termin a l
Bo a rd
NOTE S :
RACEWAY
HOLE IN END PANEL (HIDDEN)
DIP
SWITCHES
SPEED-UP
JUMPERS