Bryant 549B Series, Installation, Start-Up And Service Instructions Manual

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B. Field Control Wiring
Install a Bryant-approved accessory thermostat assembly
according to installation instructions included with the
accessory. Locate the thermostat assembly on a solid wall in
the conditioned space to sense average temperature in accor-
dance with thermostat installation instructions.
NOTE: If using a Bryant electronic thermostat, set the ther-
mostat configuration for “non-heat pump operation.” This
family of products does not require an “O” terminal to ener-
gize the reversing valve.
Route the thermostat cable or equivalent single leads of col-
ored wire from the subbase terminals to the low-voltage con-
nections on the unit (shown in Fig. 7) as described in Steps 1
through 4 below.
NOTE: For wire runs up to 50 ft, use no. 18 AWG (American
Wire Gage) insulated wire (35 C minimum). For 51 to 75 ft,
use no. 16 AWG insulated wire (35 C minimum). For over
75 ft, use no. 14 AWG insulated wire (35 C minimum). All
wire larger than no. 18 AWG cannot be directly connected to
the thermostat and will require a junction box and splice at
the thermostat.
1. If the unit is mounted on roof curb and accessory
thru-the-curb service plate connection is used, route
wire through the connection plate.
2. Pass control wires through the hole provided on the
unit (see connection D in Connection Sizes table
Fig. 5).
3. Feed wire through the raceway built into the corner post
to the 24-v barrier located on the left side of the control
box. See Fig. 8. The raceway provides the UL required
clearance between the high-and low-voltage wiring.
4. Connect the thermostat wires to the screw terminals
of the low-voltage connector (see Fig. 7).
NOTE: If thru-the-bottom power connections are used refer
to the accessory installation instructions for information on
power wiring. Refer to Fig. 5 for drilling holes in the
basepan.
C. Defrost Board
The defrost board timer cycle is set to 30 minutes. To change
the cycle time, remove the wire from defrost board connected
to the 30 minute quick-connect. See Fig. 9. Connect the wire
to the 50 to 90 minute quick-connects on the defrost board,
depending on the desired defrost time.
D. Heat Anticipator Settings
For units with electric heat, set heat anticipator settings as
shown in Table 4.
VI. STEP 6 — ADJUST FACTORY-INSTALLED OPTIONS
A. Disconnect Switch
The optional disconnect switch is non-fused. The switch can
be locked in place for safety purposes. The disconnect has a
maximum rating of 80 amperes and cannot be used if rooftop
electrical rating exceeds 80 amperes.
B. Manual Outdoor-Air Damper
The outdoor-air hood and screen are attached to the basepan
at the bottom of the unit (for shipping).
Assembly:
1. Determine the amount of ventilation required for the
building. Record the amount for use in Step 8.
2. Remove the filter access panel by raising the panel
and swinging it outward. The panel is now disen-
gaged from the track and can be removed. No tools
are required to remove the filter access panel.
Remove the outdoor-air opening panel. Save panels
and screws. See Fig. 10.
3. Separate the hood and screen from the basepan by
removing the screws and brackets securing them.
Save all screws and discard brackets.
4. Replace the outdoor air opening panel.
5. Place the hood on the front of the outdoor air opening
panel. See Fig. 11 for hood details. Secure the top of
the hood with the 6 screws removed in Step 3. See
Fig. 12.
6. Remove and save the 8 screws (4 on each side) from
the sides of the manual outdoor-air damper.
7. Align the screw holes on the hood with the screw
holes on the side of manual outdoor-air damper. See
Fig. 11 and 12. Secure the hood with the 8 screws
from Step 6.
8. Adjust the minimum position setting of the damper
blade by adjusting the manual outdoor-air adjust-
ment screws on the front of the damper blade. See
Fig. 10. Slide the blade vertically until it is in the
appropriate position determined by Fig. 13. Tighten
the screws.
9. Remove and save the screws currently on the sides of
the hood. Insert the screen. Secure the screen to the
hood using the screws. See Fig. 12.
10. Replace the filter access panel. Ensure that the filter
access panel slides along the tracks and is securely
engaged.
Table 4 — Heat Anticipator Settings
*kW is based on 240 or 480 v.
UNIT
UNIT VOLTAGE
208/230 460
Heater kW*
Configuration
Heater kW*
Configuration
1-Stage
2-Stage
1-Stage
2-Stage
Stage 1 Stage 2 Stage 1 Stage 2
549B
10.4, 16.0 0.3 NA NA
13.9, 16.5
27.8, 33.0
0.3 NA NA
24.8, 32.0 0.6 0.3 0.3
42.4, 50.0 0.9 0.6 0.3 41.7, 50.0 0.6 0.3 0.3