Installation manual

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 Conne ction Pin Number Unit C onnection Note
GFan 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
RPower 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
T B --- W 2 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 C onfiguration
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
38AUQ