Auxiliary (Electric) Heat Control; Defrost - Carrier Legacy 548J07 Installation Instructions Manual

POINT NAME
INPUTS
G Fan
Y1 Cool 1
Y2 Cool 2
W1 Heat 1
W2 Heat 2
R Power
C Common
DFT 1
DFT 2
OUTPUTS
IFO Fan On
OF OD Fan On
RVS1
RVS2
COMP 1
COMP2
HEAT 2
COM
CONFIGURATION
Select Jumper
2 Compressor
SPEED-UP CONFIGURATION
Speed-Up Jumper
Speed-Up Jumper
NOTES:
1. 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).
2. Jumper for 5-20 seconds: Forced Defrost — Defrost runs for 30 seconds if DFT2 is open.
1 2

1

0
30 minutes
(factory default)

AUXILIARY (ELECTRIC) HEAT CONTROL

The 548J unit can be equipped with one or two auxiliary elec-
tric 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 (compres-
sors are off and only the electric heaters are energized) and also
during the Defrost cycle (to eliminate a "cold blow" condition
in the space).
Fig. 38 — Defrost Control Board Location
Table 6 — 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
DI, 24 vac
DO, 24 vac
DO, 24 vac
DO, 24 vac
DO, 24 vac
DO, 24 vac
DO, 24 vac
DO, 24 vac
24 vac
24 vac
24 vac
—
—
Table 7 — DIP Switch Positions
1 2
 
1
 
0
60 minutes
UNIT CONNECTION
P2-3
P2-5
P2-4
P2-7
P2-6
P3-1
P3-2
DFT-1 to DFT-1
DFT-2 to DFT-2
P3-9
OF
P3-7 to P3-5
P3-6 to P3-4
P3-10 FPT1-REHEAT/HP-6
P3-8 FPT2-REHEAT/HP-8
E-HEAT
P3-3
P1-1
P1-3
JMP17
JMP18
1 2
1
 
0
90 minutes

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 cy-
cle) during which no defrost will be permitted. This period can
be set at 30, 60, 90 or 120 minutes by changing the positions of
24
CTB-G
CTB-Y1
CTB-Y2
CTB-W1
CTB-W2
CONTL BRD-8
CONTL BRD-4
—
—
REHEAT/HP-2
OFR
— Energize in COOL
— Energize in COOL
TB4-1
TB4-3
—
— Use for 548JD
—
—
1 2
 
1
0
120 minutes
NOTE
3

On
Off
Fan Delay