527 01 2701 00
Specifications subject to change without notice.
19
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.
Operation of the reversing valves is based on internal logic;
this application does not use an “O” or “B” signal to deter
-
mine reversing valve position. Reversing valves are ener
-
gized during the cooling stages and the defrost cycle and
de-energized during heating cycles. Once energized at the
start of a cooling stage, the reversing valve will remain ener
-
gized until the next heating cycle demand is received. Once
de-energized at the start of a Heating cycle, the reversing
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; 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).
Auxiliary (Electric) Heat control
The RHW unit can be equipped with one or two auxiliary
electric 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 compres
-
sor(s) in the Stage 1 Heating cycle), for an Emergency
Heating sequence (compressors are off and only the elec
-
tric 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 compo
-
nent 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 Heat
-
ing cycle) during which no defrost will be permitted. This pe
-
riod can be set at 30, 60, 90 or 120 minutes by changing the
positions of DIP switches SW1 and SW2 (see Fig. 31 and
Table 4). The default run period is 30 minutes.
Fig. 31 — DIP Switch Settings - Defrost Board
Table 3 —
RHW 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 4 —
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 RHW036-060
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