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VOLTS FREE CONTACTS
Voltage free contacts are rated at 115VAC, 100VA re-
sistive load only. Inductive loads must be suppressed
across the coil.
Chilled Liquid Pump Starter
Terminals 23 and 24 on 1TB close to start the chilled
liquid pump. This contact can be used as a master start/
stop for the pump in conjunction with the daily start/
stop schedule. Cycle the pumps from the unit panel if
the unit will be operational or shut-down during sub-
freezing conditions. Refer to the Evaporator Pump
Control on Page 206 for more information on testing
the pumps.
Run Contact
Terminals 21 and 22 on 1TB close to indicate that a
system(s) is (are) running.
Alarm Contacts
The Systems 1/3 & 2/4 each have a single voltage-free
contact, which will operate to signal an alarm condition
whenever any system locks out, or there is a power
failure. To obtain system alarm signal, connect the
alarm circuit to volt free Terminals 25 & 26 (Sys 1/3),
Terminals 27 and 28 (Sys 2/4) of 1TB.
SYSTEM INPUTS
Flow Switch
A chilled liquid flow switch of suitable type MUST be
connected between Terminals 2 and 13 of 1TB to provide
protection against loss of liquid flow, which will cause
evaporator freeze-up if the chiller is permitted to run.
The flow switch circuitry is a 115VAC circuit. Contacts
must be rated for low current (10ma). Gold contacts
should be used.
Remote Run / Stop
A Remote Run/Stop input is available for each pair of
systems (1/3 & 2/4). These inputs require a dry contact
to start and stop the system. System 1/3 remote dry
contacts are connected between Terminals 2 and 15 of
1TB and System 2/4 dry contacts are connected between
Terminals 2 and 16 of 1TB . If remote start/stop is not
JOHNSON CONTROLS
utilized, a jumper must be paced across the terminals to
allow the system to run. The remote run/stop circuitry is
a 115VAC circuit. Contacts must be rated for low current
(10ma). Gold contacts should be used.
Remote Print
Closure of suitable contacts connected to Terminals 2
and 14 of 1TB will cause a hard copy printout of Operat-
ing Data/Fault History to be made if an optional printer is
connected to the RS-232 port. The remote print circuitry
is a 115VAC circuit. Contacts must be rated for low cur-
rent (10ma). Gold contacts should be used.
Optional Remote Setpoint Offset – Temperature
A current or voltage signal connected to Terminals
17 and 18 will provide a remote offset function of the
chilled liquid setpoint, if required. See Page 228 for a
description of the option.
Optional Remote Setpoint Offset – Current
A current or voltage signal connected to Terminals 19
and 20 will provide remote setting of the current limit
setpoint, if required. See FIG. 22 on page 176 for the
input location and Page 230 for a description of the
option.
Optional Remote Setpoint Offset – Sound Limiting
A current or voltage signal connected to Terminals
40 and 41 will provide remote setting of sound limit
setpoint, if required. See Page 232 for a description of
the option.
FORM 201.21-NM3 (616)
4
35
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