Technical Guide

505428-YTG-R-1114
Johnson Controls Unitary Products 123
Typical Field Wiring Diagram - NC120 thru 240 Evaporator Unit with YC120 thru 240 Condenser Unit
NOTE: On non NC/ND Evaporator models, isolation relays
must be installed to avoid overloading on 75 VA
transformers on the condensing unit.
THERMOSTAT
TWO STAGE COOLING
TWO STAGE HEATING
G C
Y1
RW1 W2 X
Y2
NOTE: Liquid line solenoid is only activated during
second stage cooling operation.
219 / Y
218 / BR
1LLS
VALVE SYS 2
BLK
BLK
C O I L