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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
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.
Reversing valve control
The DFB has two outputs for unit reversing valve control. Opera-
tion of the reversing valves is based on internal logic; this applica-
tion does not use an "O" or "B" signal to determine reversing
valve position. Reversing valves are energized during the cooling
stages and the defrost cycle and de-energized during heating cy-
cles. 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 re-
versing valves will remain de-energized until the next cooling
stage is initiated.
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 (SystemVu
™
generates commands to start compressors with or without revers-
ing valve operation to produce Stage 1 Cooling (one compressor
runs), Stage 2 Cooling (both compressors run) or Stage 1 Heating
(both compressors run).
Auxiliary (Electric) Heat control
The 50FCQ 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 (compressors
1
2
1
•
0
•
30 minutes
(factory default)
Table 3 — 50FCQ 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
—
—
controller or RTU Open controller); it
Table 4 — DIP Switch Positions
1
2
1
•
0
•
60 minutes
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
P3-8
E-HEAT
P3-3
P1-1
JMP17
JMP18
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. 32 and Table 4). The default run
period is 30 minutes.
Fig. 32 — DIP Switch Settings - Defrost Board
1
2
1
1
0
•
•
0
90 minutes
19
UNIT CONNECTION
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
FPT1-REHEAT/HP-6
FPT2-REHEAT/HP-8
TB4-1
TB4-3
—
—
—
1
2
•
•
1
0
120 minutes
NOTE
3
•
On
Off
Fan Delay
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