JOHNSON CONTROLS
75
SECTION 2 – INSTALLATION
FORM 145.05-NOM7
ISSUE DATE: 10/31/2019
FIELD WIRING
shows the field control wiring
to CTB1. All field control wiring is field supplied and
installed.
Space Sensor
The space sensor (if used) can be used on either CV or
VAV units. When mounting a space sensor, it should be
located on an inside wall approximately 56" above the
floor where it is not subjected to drafts, sun exposure or
heat from electrical fixtures or appliances.
Shielded Wire must be used that is
grounded at control panel only.
Occupied / Unoccupied Input
There are several ways to place the unit in the Occu-
pied mode. The unit has a three position rocker switch
identified as OFF, AUTO, ON. When the switch is in
the ON position the OCC terminal on the terminal strip
is energized through the rocker switch. This places the
unit in the Occupied mode. With the rocker switch in
the AUTO position the unit can be placed in the Oc-
cupied mode by a communicated input through a BAS
system internal schedule, or by closing a circuit be-
tween 24V and OCC on the terminal strip. A hardwired
external device like a time clock or manual switch
could be used to close this circuit.
Contact Closure = Occupied
Contact Open = Unoccupied
Note that 24 volts (24VAC), terminal 1 of the terminal
block CTB1, must be used as the 24VAC source for the
external contact. Use of any power source external to the
controller results in damage to the Unit Controller.
Shutdown Input
The unit has a three position rocker switch identified as
OFF, AUTO, ON. When the switch is in the AUTO or
ON position the SD terminal on the terminal strip is en-
ergized through the rocker switch. When the circuit is
open, the unit turns OFF the supply fan and terminates
all normal operation.
This same circuit can be used as a means of institut-
ing an external shutdown command. Wire 261 can be
removed from terminal 3 (SD) of terminal block CTB1
and connected to a wire running to a normally closed
contact of the external shutdown device. A wire can
be connected to the other side of the normally closed
external contact to terminal 3 (SD) of terminal block
CTB1.
Contact Closed = Normal Operation
Contact Open = Shutdown
VAV Heat Relay Output
This is a field wired output that is used to command
the VAV boxes to full open during morning warm up
operation. This 24VAC signal should have a maximum
current draw not to exceed 20VA. If the VA require-
ment of the VAV boxes approaches 20VA, isolation
relays should be field supplied and installed to avoid
overloading the unit power supply.
Failure to drive the VAV boxes open during this mode
of operation can cause unit shutdown and/or damage to
the ductwork due to over-pressurization.
The VAV Heat Relay Output cannot ex-
ceed a current draw of 20VA. If the power
requirements of the VAV boxes exceed this
amount, isolation relays must be field sup-
plied and installed to prevent overloading
the Unit Controller power supply.
BACNET COMMUNICATION
The Water Cooled Self Contained Unit can com-
municate to any building automation system using
BACNET
MSTP
communication protocol.
The field connections are made by connecting shielded
two-wire cable to TB1 on the
IPU
control board.
Refer to Communication on page 169 for additional
information.