13
Scholar V VAIVA Maintenance & Service Manual 10/2017 Rev.2
PLC Connections and Indicator Lights
Loss off
Charge
High
Pressure
Discharge
Temp
Not
Used
Freeze
Stat
Temp
Transducer
RH
Transducer
0 – 20 ma
Blower Speed
0 – 20 ma
Comp Speed
Input
Status Lights
Output
Status Lights
Compressor
Enable
Reversing
Valve
Reheat
Valve
Outdoor
Fan #1
Resistance
Heat Contactor
Outdoor
Fan #2
Indoor
Blower Enable
Ventilation
500 ohm
resistor
Figure 6. Scholoar V PLC
A. Digital Inputs:
All digital inputs are powered by 24 VDC
• DI 0.0 –
Low Refrigerant Pressure Switch:
Opens on refrigerant evaporator
pressure drop
• DI 0.1 –
High Refrigerant Pressure Switch
: Opens on refrigerant condenser
pressure rise
• DI 0.2 –
High Compressor Discharge Temperature:
Opens on temperature rise of
the compressor discharge refrigerant line