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28
DIP
Switches
Speed-Up
Jumpers
C09275
Fig. 23 -- Defrost Control Board (DFB) Arrangement
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
determine reversing valve position. Reversing valves are
energized during the Cooling stages and de-energized during
Heating cycles. 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 reversing valves will
remain de-energized until the next Cooling stage is initiated.
Compressor Control —
The DFB receives inputs indicating Stage 1 Cooling and
Stage 1 Heating from the space thermostat or unit control
system (PremierLink); it generates commands to start
compressors with or without reversing valve operation to
produce Stage 1 Cooling (one compressor), or Stage 1
Heating (both compressors run).
Table 8 – 38AUQ Defrost Board I/O and Jumper Configurations
Inputs
Point Name
Type of I/O
Connection Pin Number
Unit Connection
Note
G Fan
DI, 24-vac
P2-3
Not used
Y1 Cool 1
DI, 24-vac
P2-5
TB-Y1
Wi Heat 1
DI, 24-vac
P2-7
TB-W1
R Power
24-vac
P3-1
TRAN2
C Common
24-vac, ground
P3-3
TRAN2
DFT1 Defrost Switch
DI, 24-vac
DFT-1 to DFT-1
DFB
DFT2 Defrost Switch
DI, 24-vac
DFT-2 to DFT-2
DFB
Outputs
Point Name
Type of I/O
Connection Pin Number
Unit Connection
Note
OF OD Fan
DO, 24-vac
OF
OFR
RVS1
DO, 24-vac
P3-7 to P3-5
RVS1
Energize in COOL
RVS2
DO, 24-vac
P3-6 to P3-4
RVS2
Energize in COOL
COMP 1
DO, 24-vac
P3-10
CADM1-Y
TB---W2
DO, 24-vac
E-HEAT
HR
Configuration
Point Name
Type of I/O
Connection Pin Number
Unit Connection
Note
Select Jumper
24-vac
P1-1
1 Compressor
24-vac
P1-2
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 secs: Factory Test, defrost runs for 12 seconds or less
Jumper for 5-20 secs: Forced Defrost, defrost runs for 30 secs if DFT2 is open
C10789
Fig. 24 -- Defrost Control Board (DFB) Location
38A
U
Q
Summary of Contents for 38AUQ 16 Series
Page 4: ...4 C10675 Fig 2 38AUQ 25 Unit Dimensions 38AUQ...
Page 19: ...19 C10784 Fig 16 38AUQ 16 Charging Chart 38AUQ...
Page 20: ...20 C10785 Fig 17 38AUQ 25 Charging Chart 38AUQ...
Page 21: ...21 C10786 Fig 18 38AUQ 16 Power Schematic 208 230 3 60 shown 38AUQ...
Page 22: ...22 C10787 Fig 19 38AUQ 25 Power Schematic 208 230 3 60 shown 38AUQ...
Page 23: ...23 C10788 Fig 20 38AUQ 16 25 Control Schematic 38AUQ...
Page 41: ...41 C10363 Fig 35 Wind Baffles Fabrication 38AUQ...
Page 42: ...42 C10366 Fig 36 15 Ton Wind Baffle Brackets Fabrication 38AUQ...
Page 44: ...44 RIGHT BACK LEFT FRONT C10368 Fig 38 Wind Baffle Installation 20 Ton Units 38AUQ...
Page 45: ...45 38AUQ...