JOHNSON CONTROLS
38
SECTION 4 - INSTALLATION
Form 201.47-ICOM1
Issue date: 17/11/2022
Volts free contacts
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. See Evaporator Pump Control on
Page 100, for more information on testing the pumps.
Run contact
Terminals 21 and 22 on 1TB close to indicate that a
system is running.
Alarm contacts
Each system has 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), Terminals 27 and 28
(Sys 2) 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 pro-
vide 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 115 VAC circuit.
Contacts must be rated for low current (5 mA). Gold
contacts should be used.
Generally, the thermal dispersion flow switch is
shipped with the unit as a loose part.
To mount the IFM thermal dispersion switch, use the
following guidelines:
• Use a pipe coupling to mount the thermal disper-
Figure 17 on page 39.
The length of the pipe coupling must be suitable
to ensure that the insertion depth of the sensor is
at least 12 mm.
• -
zontal pipes from the side. If it has to be mounted
in vertical pipes, mount the switch in the rising pipes.
•
top of the horizontal pipes only if the pipe is fully
only if the pipe is free from buildup.
• Ensure that the sensor tip does not contact the pipe
wall. Do not mount it in a downpipe, in which the
• Avoid turbulence of the liquid resulting from
Ensure that the distance from the potential turbu-
lence upstream or downstream of the sensor loca-
tion is at least 5 times of the pipe diameter.
•
directly. No extension cable between them is al-
lowed.
Run permissive
A run permissive input is available for each system.
These inputs require a dry contact to start and stop the
system. System 1 remote dry contacts are connected
between Terminals 2 and 15 of 1TB and System 2 dry
contacts are connected between Terminals 2 and 16 of
1TB. If run permissive is not utilized, a jumper must
be paced across the terminals to allow the system to
run. The run permissive circuitry is a 115 VAC circuit.
Contacts must be rated for low current (5 mA). Gold
contacts must 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 cir-
cuitry is a 115 VAC circuit. Contacts must be rated for
low current (5 mA). Gold contacts should be used.
Optional remote setpoint offset – temperature
A voltage signal connected to Terminals 17 and 18 of
1TB will provide a remote offset function of the chilled
liquid setpoint, if required.
Optional remote setpoint offset – current
A voltage signal connected to Terminals 19 and 20
of 1TB will provide a remote setting of current limit
setpoint, if required.
Optional remote setpoint offset – sound
limiting
A voltage signal connected to Terminals 40 and 41 of
1TB will provide remote setting of sound limit setpoint,
if required.
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