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Thermostat wiring
Install the thermostat on an inside wall approximately 56 inches
above the floor. The thermostat must not be subject to drafts,
sun exposure, or heat from electrical fixtures or appliances.
Follow the manufacturer's instructions enclosed with thermostat
for the general installation procedure. Use color-coded,
THERMOSTAT
TERMINALS
W1
W2
1
Y1
Y2
G
R
3
C
RC
4
OCC
5
X
TERMINALS ON A
LIMITED NUMBER
OF THERMOSTATS
S4
-
1)
RAH
+
2)
-
3)
DCT
+
PRS
4)
Second stage
1
2
Jumper is required if there is no Smoke Detector circuit.
Jumper is required for any co
3
OCC is an output from the thermostat to indicate the Occupied
4
5
X is an input to the thermostat to display Error Status condi ons.
Figure 24: Typical low voltage field wiring
208/230-3-60 and 380/415-3-50 units control
transformers are factory wired for 230v and 415v power
supply respectively. Change the tap on the transformer
for 208-3-60 or 380-3-50 operation. See the unit wiring
diagram.
Johnson Controls Ducted Systems
CONTROL
TERMINAL
BLOCK
SD-24
TB4-3
823/R
24V
Return or Space Humidity
COM
824/BK
Sensor (0-10VDC)
OUT
825/W
ot required on single stage he
g units.
of R, RC, or RH.
insulated wires to connect the thermostat to the unit. See Table
9 for control wire sizing and maximum length.
Table 9: Control wire sizes
Wire size
18 AWG
R~Occ Jumper:
Smart Equipment Control boards come from the
factory with a jumper wire between R and OCC
terminals on the thermostat terminal strip. Failure
W1
to remove this jumper will place the unit into the
W2
Occupied mode no matter what the occupancy
demand is from the thermostat or EMS system.
Y1
To allow Thermostat or EMS control of the
G
Occupied mode for the unit, this jumper must be
removed during commissioning.
Y2
OCC
X
R
C
C
24V
SD-24
Jumper Located on Harness
(If No Smoke Detector)
SD-R
R
on.
5121835-TIM-J-1118
Maximum length
150 feet
Smoke
Detector
24 VAC
Class 2
2
(If Smoke Detector Is Used)
24V Output
1
19
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