Bryant 548J Service And Maintenance Instructions page 22

Inputs
Point Name
G Fan
Y1 Cool 1
Y2 Cool 2
W1 Heat 1
W2 Heat 2
R Power
C Common
DFT1
DFT 2
Outputs
Point Name
IFO Fan On
OF OD Fan On
RVS1
RVS2
COMP 1
COMP 2
HEAT 2
COM
Configuration
Point Name
Select Jumper
2 Compressor
Speed- - Up Configuration
Point Name
Speed --- Up Jumper
Speed --- Up Jumper
Jumper for 1- -3 secs: Factory Test, defrost runs for 9 secs
Jumper for 5- -20 secs: Forced Defrost, defrost runs for 30 secs if DFT2 is open
Reversing valve control — The DFB has two outputs for
unit reversing valve control. Operation of the reversing
valves is based on internal logic; this application does not
use an "O" or "B" signal to determine reversing valve
position. Reversing valves are energized during the
Cooling stages and de- - energized during Heating cycles.
Once energized at the start of a Cooling stage, the
reversing valve will remain energized until the next
Heating cycle demand is received. Once de- - energized at
the start of a Heating cycle, the reversing valves will
Fig. 27 - - Defrost Control Board (DFB) Location
Table 9 – 548J Defrost Board I/O and Jumper Configurations
Type of I/O Connection Pin Number
DI, 24--- vac
DI, 24--- vac
DI, 24--- vac
DI, 24--- vac
DI, 24--- vac
24--- vac
24--- vac
DI, 24--- vac DFT--- 1 to DFT--- 1
DI, 24--- vac DFT--- 2 to DFT--- 2
Type of I/O Connection Pin Number
DO, 24--- vac
DO, 24--- vac
DO, 24--- vac P3--- 7 to P3--- 5
DO, 24--- vac P3--- 6 to P3--- 4
DO, 24--- vac P3--- 10
DO, 24--- vac
DO, 24--- vac E--- HEAT
24--- vac
Type of I/O Connection Pin Number
24--- vac
24--- vac
Type of I/O Connection Pin Number
JMP17
JMP18
Unit Connection
P2--- 3 LCTB--- G
P2--- 5 LCTB--- Y1
P2--- 4 LCTB--- Y2
P2--- 7 LCTB--- W1
P2--- 6 LCTB--- W2
P3--- 1 CONTL BRD--- 8
P3--- 2 CONTL BRD--- 4
Unit Connection
P3--- 9 REHEAT--- 2
OF
FPT --- REHEAT--- 6
P3--- 8 REHEAT--- 8
HC --- 1 (TB4--- 1)
P3--- 3 HC --- 1 (TB4--- 3)
Unit Connection
P1--- 1
P1--- 3
Unit Connection
remain de- - energized until the next Cooling stage is
initiated.
Compressor control — The DFB receives inputs
indicating Stage 1 Cooling, Stage 2 Cooling (sizes 08 and
09 only) and Stage 1 Heating from the space thermostat or
unit control system (RTU- - MP); it generates commands to
start compressors with or without reversing valve
operation to produce Stage 1 Cooling (one compressor),
Stage 2 Cooling (both compressors run) or Stage 1
Heating (both compressors run).
22
Note
Note
OFR
Energize in COOL
Energize in COOL
Note
Use for 548J***D
Note
C09276