Bryant 548D User Manual
Page 12
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12
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Table 3 — Heat Anticipator Settings
*Heater capacity (kW) is based on heater voltage of 208 v, 240 v,
480 v and 575 v. If power distribution voltage to unit varies from
rated heater voltage, heater kW will vary accordingly.
4. On size 120 units, install vertical discharge block-off
plate over duct openings. See Fig. 13.
5. Economizer is factory-installed in unit and secured
with screws. See Fig. 14.
NOTE: Be sure rear economizer flange is engaged under tabs
in vertical return-air opening.
6. To convert to horizontal discharge application:
a. Rotate the economizer 90 degrees until the econ-
omizer motor faces the outdoor section (see
Fig. 15).
b. Remove shipping screw and tape from baromet-
ric damper and rotate the barometric relief
damper hinge 90 degrees. Barometric relief
damper should open vertically to operate
properly.
c. Install horizontal discharge block-off plate over
the opening on the access panel. (Block-off plate
MUST be installed before installing hood assem-
bly.) See Fig. 16.
7. Remove existing 12-pin blue and yellow wire jumper
plug and store. Insert 12-pin economizer plug into
economizer harness. See Fig. 14.
8. If ventilation air is not required, proceed to Step 9. If
ventilation air is required, determine the minimum
position setting for required airflow. See Fig. 17.
Adjust minimum position setting by loosening the
screws on the position setting bracket. See Fig. 18.
Slide bracket until the top screw is in the position
determined by Fig. 17. Tighten screws.
9. Remove tape and shipping screw from outdoor-air
thermostat (OAT). Fas-ten OAT to inside of hood
using screws and speed clips provided. See Fig. 19.
Make sure OAT terminals are positioned up.
10. Replace outdoor-air opening panel using screws from
Step 2. Replace filter access panel. Ensure the filter
access panel slides along the tracks and is securely
engaged.
11. Fasten hood top and side plate assembly to outdoor-
air opening panel with screws provided.
12. Place knob supplied with economizer on OAT. See
Fig. 19. Set for 3° F below indoor room thermostat
setting. If accessory enthalpy control (EC) is used in
place of OAT, see instructions shipped with EC for
installation and adjustment. See Fig. 19.
13. Connect OAT per Fig. 20.
14. Slide outdoor-air inlet screen into screen track on
hood side plate. While holding screen in place, fasten
screen retainer to hood using screws provided.
NOTE: Refer to Fig. 21 for economizer barometric relief
damper characteristics.
UNIT
UNIT VOLTAGE
208/230
460
575
Heater
kW*
Configuration
Heater
kW*
Configuration
Heater
kW*
Configuration
1-Stage
2-Stage
1-Stage
2-Stage
1-Stage
2-Stage
Stage 1
Stage 2
Stage 1
Stage 2
Stage 1
Stage 2
548D
10.4, 16.0
0.3
NA
NA
13.9, 16.5
27.8, 33.0
0.3
NA
NA
17.0, 34.0
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
51.0
0.6
0.3
0.3
Fig. 10 — Defrost Board
Fig. 11 — Panel Locations