Quantech QTC40160, Installation Operation & Maintenance

Page: 38 / 188

Quantech
38
Section 4 - Installation
Form QTC4-NM2
Issue date: 05/12/2023
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 102
, 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
operates to signal an alarm condition whenever any
system locks out, or when a power failure occurs. To
obtain system alarm signal, connect the alarm circuit to
volt free Terminals 25 and 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 can
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). Use
gold contacts.
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-
sion flow switch. See Figure 18 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.
• Mount the thermal dispersion flow switch in hori -
zontal pipes from the side. If it has to be mounted
in vertical pipes, mount the switch in the rising pipes.
• Mount the thermal dispersion flow switch on the
top of the horizontal pipes only if the pipe is fully
filled with liquid. Mount the thermal dispersion
flow switch on the bottom of the horizontal pipes
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
liquid flows downwards.
• Avoid turbulence of the liquid resulting from
bends, valves, reducers, and other pipe fittings.
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.
• Connect the control monitor with the flow sensor
directly. Do not use an extension cable between
them.
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 used, 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 circuitry
is a 115 VAC circuit. Contacts must be rated for low cur-
rent (5 mA). Use gold contacts.
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.