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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 166 for more information on testing
the pumps.
Run Contact
Terminals 21 and 22 on 1TB (see FIG. 22, Page 136)
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 (see
FIG. 22, Page 136) 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 con-
tact 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 (see FIG. 22, Page
JOHNSON CONTROLS
JOHNSON CONTROLS
136). If remote start/stop is not 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 (see FIG. 22, Page 136) will cause a
hard copy printout of Operating 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 current (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 188 for a
description of the option.
Optional Remote Setpoint Offset – Current
A current or voltage signal connected to Terminals 19
and 20 of 1TB (see FIG. 22, Page 136) will provide
remote setting of the current limit setpoint, if required.
See FIG 22 on Page 136 for the input location and Page
190 for a description of the option.
Optional Remote Setpoint Offset – Sound Limiting
A current or voltage signal connected to Terminals 40
and 41of 1TB (see FIG. 22, Page 136) will provide
remote setting of sound limit setpoint, if required. See
Page 192 for a description of the option.
FORM 201.21-NM4 (616)
4
35
35
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