Bryant 548J*17 D Series, Installation Instructions Manual

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Compressor control — The DFB receives inputs indicating
Stage 1 Cooling, Stage 2 Cooling and Stage 1 Heating from
the space thermostat or unit control system (RTU Open
controller); it generates commands to start compressors with
or without reversing valve operation to produce Stage 1
Cooling (one compressor runs), Stage 2 Cooling (both
compressors run) or Stage 1 Heating (both compressors run).
C14049
Fig. 29 -- Defrost Control Board Location
Table 5 – 548J Defrost Board I/O and Jumper Configurations
Inputs
Point Name Type of I/O Connection Pin Number Unit Connection Note
G Fan DI, 24Vac P2---3 CTB---G
Y1 Cool 1 DI, 24Vac P2---5 CTB---Y1
Y2 Cool 2 DI, 24Vac P2---4 CTB---Y2
W1 Heat 1 DI, 24Vac P2---7 CTB---W1
W2 Heat 2 DI, 24Vac P2---6 CTB---W2
R Power 24Vac P3---1 CONTL BRD---8
C Common 24Vac P3---2 CONTL BRD---4
DFT1 DI, 24Vac DFT---1 to DFT---1 —
DFT 2 DI, 24Vac DFT---2 to DFT---2 —
Outputs
Point Name Type of I/O Connection Pin Number Unit Connection Note
IFO Fan On DO, 24Vac P3---9 REHEAT/HP---2
OF OD Fan On DO, 24Vac OF OFR
RVS1 DO, 24Vac P3---7 to P3---5 — Energize in COOL
RVS2 DO, 24Vac P3---6 to P3---4 — Energize in COOL
COMP 1 DO, 24Vac P3---10 FPT1 --- REHEAT/HP---6
COMP 2 DO, 24Vac P3---8 FPT2 --- REHEAT/HP---8
HEAT 2 DO, 24Vac E---HEAT TB4---1
COM 24Vac P3---3 TB4---3
Configuration
Point Name Type of I/O Connection Pin Number Unit Connection Note
Select Jumper 24Vac P1---1 —
2 Compressor 24Vac P1---3 — Use for 548J***D
Speed--Up Configuration
Point Name Type of I/O Connection Pin Number Unit Connection Note
Speed---Up Jumper — JMP17 —
Speed---Up Jumper — JMP18 —
Jumper for 1---3 seconds: Factory Test — The defrost interval timing is reduced by a factor of 0.1 seconds/minute based on the positions of
DIP switches SW1 and SW2 (i.e. 90 minutes will be reduced to 9 seconds).
Jumper for 5---20 seconds: Forced Defrost — Defrost runs for 30 seconds if DFT2 is open.