AVPTC Service Manual

PRODUCT DESIGN

Communicating Unitary Control (UC) PCB

The Communicating System Unitary Control PCB is a micro-

processor-based control for heat pump and air conditioning

condensing units with single-phase compressors up to 5 ton

capacity operating on standard residential or Delta and Wye

commercial power. The control incorporates the basic func-

tionality of existing defrost controls, outdoor thermostats,

contactors, compressor staging controls, short cycle con-

trols, line voltage monitors, Comfort Alert™ or CoreSense

Module (dependent upon which module you are using), two

speed condenser fan relays and the Active Protection com-

ponent of enabled thermostats. The control is designed to

work as part of a fully communicating HVAC system with 4

wires. The control also supports legacy 24VAC thermostat

inputs for Y1, Y2, O and 24VAC outputs for RVS, W1, and L

for non-communicating systems. Outputs include compres-

sor power, compressor stage select, and outdoor fan high

and outdoor fan low speed. System inputs include high/low

pressure switches, as well as thermistor inputs for outdoor

coil temperature and outdoor air temperature.