20
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 (RTU Open controller); it generates commands to
start compressors with or without reversing valve operation to pro
-
duce Stage 1 Cooling (one compressor runs), Stage 2 Cooling
(both compressors run) or Stage 1 Heating (both compressors run).
Auxiliary (Electric) Heat control
The 547K unit can be equipped with one or two auxiliary electric
heaters, to provide a second stage of heating. The DFB will ener
-
gize 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 De
-
frost 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. 33 and Table 8). The default run
period is 30 minutes.
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 de
-
frost 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.
Fig. 33 — DIP Switch Settings - Defrost Board
Table 7 — 547K Defrost Board I/O and Jumper Configurations
POINT NAME
TYPE OF I/O
CONNECTION PIN NUMBER
UNIT CONNECTION
NOTE
INPUTS
G Fan
DI, 24 vac
P2-3
CTB-G
Y1 Cool 1
DI, 24 vac
P2-5
CTB-Y1
Y2 Cool 2
DI, 24 vac
P2-4
CTB-Y2
W1 Heat 1
DI, 24 vac
P2-7
CTB-W1
W2 Heat 2
DI, 24 vac
P2-6
CTB-W2
R Power
24 vac
P3-1
CONTL BRD-8
C Common
24 vac
P3-2
CONTL BRD-4
DFT 1
DI, 24 vac
DFT-1 to DFT-1
—
DFT 2
DI, 24 vac
DFT-2 to DFT-2
—
OUTPUTS
IFO Fan On
DO, 24 vac
P3-9
REHEAT/HP-2
OF OD Fan On
DO, 24 vac
OF
OFR
RVS1
DO, 24 vac
P3-7 to P3-5
—
Energize in COOL
RVS2
DO, 24 vac
P3-6 to P3-4
—
Energize in COOL
COMP 1
DO, 24 vac
P3-10
FPT1-REHEAT/HP-6
COMP2
DO, 24 vac
P3-8
FPT2-REHEAT/HP-8
HEAT 2
DO, 24 vac
E-HEAT
TB4-1
COM
24 vac
P3-3
TB4-3
CONFIGURATION
Select Jumper
24 vac
P1-1
—
SPEED-UP CONFIGURATION
Speed-Up Jumper
—
JMP17
—
Speed-Up Jumper
—
JMP18
—
Table 8 — DIP Switch Positions
1
2
1
2
1
2
1
2
3
1
•
1
•
1
1
•
•
1
•
On
0
•
0
•
0
•
•
0
0
Off
30 minutes
(factory default)
60 minutes
90 minutes
120 minutes
Fan Delay
Содержание 547K
Страница 94: ...94 APPENDIX D WIRING DIAGRAMS Fig I 547K 04 06 Power Wiring Diagram 208 230 1 60 ...
Страница 95: ...95 APPENDIX D WIRING DIAGRAMS Fig J 547K 04 07 Power Wiring Diagram 208 230 3 60 ...
Страница 96: ...96 APPENDIX D WIRING DIAGRAMS Fig K 5047K 04 07 Power Wiring Diagram 460 575 3 60 ...
