Technical Guide

505428-YTG-R-1114
Johnson Controls Unitary Products 127
Typical Field Wiring Diagram - Single 4-Pipe Evaporator Unit with Twin Condenser Units
NOTE: On non NC/ND Evaporator models, isolation relays
must be installed to avoid overloading on 75 VA
transformers on the condensing unit.
RC
Y2
G W1
THERMOSTAT
TWO STAGE COOLING
SINGLE STAGE HEATING
RC
Y2
G W1
THERMOSTAT
TWO STAGE COOLING
SINGLE STAGE HEATING
Y1
Y1
X
X