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Components
7.0 COMPONENTS & CONTROLS
7.6 Variable Speed Outdoor Control (VSODC)
7.6.1 Board Features and
Connections
20 SEER heat pumps are equipped with a Variable
Speed Outdoor Control (VSODC) that interfaces
with the inverter, Digital Control Center, and
communicating air-handler or gas furnace using
serial communication. The VSODC provides
a low voltage terminal block for control wiring
and connections for various sensors, controls,
outdoor fan motor and inverter. It also has a dual
7-segment LED for displaying status and fault
codes. Buttons are provided for navigating the
control menu and to initiate and terminate various
test modes. A plug-in memory card provides
model specific information (model data) necessary
for proper unit operation and parameters for the
correct indoor air-flow. Dip switches are provided
to allow adjustment of the defrost termination
temperature, outdoor superheat setting, and
number of EXV steps. Colored LED’s are
provided to indicate if the EXV is in the process of
opening or closing.
The following is a list of features on the VSODC
and location of each.
1. Thermostat
Terminals
2. Communication
wire
terminals
3. Modbus unitary inverter communication
connection
4. Outdoor PSC Fan relay connections
5. Outdoor ambient thermistor connection
6. Coil sensor (EVAPIN) and suction thermistor
(OST) connections
7. Liquid line thermistor (OLT) connection
8. Outdoor ECM fan PWM output connection
9. Suction pressure transducer (SPT) connection
10. Liquid pressure transducer (LPT) connection
11. Electronic expansion valve connection
12. Reversing Valve Connections
13. 3 Amp fuse
14. Test and SW2 Button
15. Communications LEDs (ET – communication is
transmitting; RT – communication is receiving)
16. Memory card connection
17. Dual seven segment LED – Displays status,
diagnostic codes, fault recall, compressor
speed, superheat, and defrost menus
18. Dip Switches – Defrost Termination
Temperature (DF1, DF2)
19. Dip Switches – EXV SH Offset (SH1, SH2)
20. EXV Operational Lights (Green – EXV is
opening; Amber - EXV is closing)
CAUTION:
UNIT MAY START
SUDDENLY AND WITHOUT WARNING.
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