Bryant 548J*17 D Series, Installation Instructions Manual

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Auxiliary (Electric) Heat control — The 548J unit can be
equipped with one or two auxiliary electric heaters, to
provide a second stage of heating. The DFB will energize
this Heating System for a Stage 2 Heating Command
(heaters operate concurrently with compressor(s) in the Stage
1 Heating cycle), for an Emergency Heating sequence
(compressors are off and only the electric heaters are
energized) and also during the Defrost cycle (to eliminate a
“cold blow” condition in the space).
Defrost — The defrost control mode is a time/temperature
sequence. There are two time components: The
continuous run period and the test/defrost cycle period.
The temperature component is provided by Defrost
Thermostat 1 and 2 (DFT1 and DFT2) mounted on the
outdoor coil.
The continuous run period is a fixed time period between the
end of the last defrost cycle (or start of the current Heating
cycle) during which no defrost will be permitted. This period
can be set at 30, 60, 90 or 120 minutes by changing the
positions of DIP switches SW1 and SW2 (see Fig. 30 and
Table 6). The default run period is 60 minutes for size 17
and 24 units.
a50--- 9688
Fig. 30 -- DIP Switch Settings — Defrost Board
Shorting the jumpers for a period of 5 to 20 seconds
bypasses the remaining continuous run period and places
the unit in a Forced Defrost mode. If the controlling DFT
is closed when this mode is initiated, the unit will
complete a normal defrost period that will terminate when
the controlling DFT opens or the 10 minute defrost cycle
limit is reached. If the controlling DFT is open when this
mode is initiated, the Defrost cycle will run for 30
seconds. Both modes end at the end of the Defrost cycle.
Unit Without Thru--Base Connection Kit —
Correctly rated low voltage wire can be routed through the
rubber grommet located on the corner post adjacent to the
control box access panel. Route wire through the grommet
and then route the wire behind the corner post utilizing the
factory provided wire ties secured to the control box. This
will insure separation of the field low voltage wire and the
high voltage circuit. Route the low voltage wire to the
central terminal board. See Fig. 31.
NOTE : If utilizing the through the base connections,
route the low voltage wire through the wire ties to the
central terminal board.
Rubber
Grommet
Corner
Post
Wire
Ties
Thru the Base
Connection
C10734
Fig. 31 -- 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.
Transformer Connection for 208--v Power Supply —
All units except 208/230-v units are factory wired for the
voltage shown on the nameplate. If the 208/230-v unit is
to be connected to a 208-v power supply, the control
transformer must be rewired by moving the black wire
with the
1
/
4
-in. female spade connector from the 230--v
connection and moving it to the 208-v
1
/
4
-in. male
terminal on the primary side of the transformer. Refer to
unit label diagram for additional information.
Table 6 – DIP Switch Position
Switch No.
1 2 1 2 1 2 1 2 3
1
J
1
J
1 1
J J
1
J
On
0
J
0
J
0
J J
0 0 Off
30 minutes
60 minutes
(Factory default)
90 minutes 120 minutes Fan Delay