Control Wire Sizes; Typical Electronic Thermostat Field Wiring; Typical Field Wiring 24 Volt Thermostat - York ZJ078 Installation Manual

Thermostat Wiring (Not applicable to units with VFD)
The thermostat should be located on an inside wall
approximately 56 inch above the floor where it will not be
subject to drafts, sun exposure or heat from electrical fixtures or
appliances. Follow the manufacturer's instructions enclosed
with thermostat for general installation procedure. Seven (7)
color-coded, insulated wires should be used to connect the
1
THERMOSTAT
TERMINALS
RC
RH
Y1
Y2
W1
W2
G
C
X1
X3
X4
A1
A2
T
T
TO REMOTE SENSOR
2ET04701324 IF USED
1
Electronic programmable Thermostat 2ET0770010024 (includes subbase).
2
Terminals A1 and A2 provide a relay output to close the outdoor economizer
dampers when the thermostat switches to the set-back position.
Figure 23: Typical Electronic Thermostat Field Wiring
Figure 24: Typical Field Wiring 24 Volt Thermostat
Johnson Controls Unitary Products
UNIT TERMINALS
STRIP TB1
R
Y1
Y2
W1
W2
G
24 Volt
C
Transformer
X
2 OCC
T-STAT
W1
W2
Y1
G
Y2
C
RH
RC
thermostat to the unit. Refer to Table 7 for control wire sizing
and maximum length.
Table 7: Control Wire Sizes
Wire Size
18 AWG
1. From the unit to the thermostat and back to the unit.
208/230-3-60 and 380/415-3-50 units control
transformers are factory wired for 230v and 415v power
supply respectively. Change tap on transformer for 208-
3-60 or 380-3-50 operation. See unit wiring diagram.
W1
W2
Y1
G
OCC
UNIT CONTROL
BOARD
Y2
X
R
SD
C
524581-YIM-I-0512
1
Maximum Length
150 Feet
19