5566228-BIM-A-0818
Johnson Controls Ducted Systems
19
Thermostat Wiring
A two stage thermostat must be used and 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.
Color-coded, insulated wires should be used to connect the
thermostat to the unit. Refer to Table 8 for control wire sizing
and maximum length.
Figure 22: Typical Low Voltage Field Wiring
Table 8: Control Wire Sizes
Wire Size
Maximum Length
1
1. From the unit to the thermostat and back to the unit.
18 AWG
150 Feet
OCC
C
RC
G
Y2
Y1
W2
W1
X
R
THERMOSTAT
TERMINALS
CONTROL
TERMINAL
BLOCK
TERMINALS ON A
LIMITED NUMBER
OF THERMOSTATS
1
4
3
1
4
Second stage
ŚĞĂƟŶŐŶ
ot required on single stage he
ĂƟŶ
g units.
Jumper is required for any co
ŵďŝŶĂƟŽŶ
of R, RC, or RH.
5
5
OCC is an output from the thermostat to indicate the Occupied
ĐŽŶĚŝƟ
on.
X is an input to the thermostat to display Error Status condi
Ɵ
ons.
3
W2
Y1
G
OCC
Y2
X
R
SD-24
C
W1
24V
COM
OUT
Return or Space Humidity
Sensor (0-10VDC)
TB4-3
823/R
-
+
+
RAH
DCT
PRS
-
P4
1)
2)
3)
4)
825/W
824/BK
S4
24V
C
24 VAC
Class 2
SD-24
Jumper Located on Harness
Smoke
Detector
SD-R
24V Output
R
(If No Smoke Detector)
(If Smoke Detector Is Used)
2
Jumper is required if there is no Smoke Detector circuit.
2
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
to remove this jumper will place the unit into the
Occupied mode no matter what the occupancy
demand is from the thermostat or EMS system.
To allow Thermostat or EMS control of the
Occupied mode for the unit, this jumper must be
removed during commissioning.