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not have a chance to return to the unloaded position
for the next startup.
NOTE: A "panic" stop (similar to "emergency" stop)
can be manually commanded using the Clear
Language Display. By pressing the STOP button
twice in a row, the chiller will immediately shut down,
but without creating a latching diagnostic.
The CLD Stop, Tracer, commanded stop, or External
Auto Stop are acceptable routine stops. In these
cases, a pre-stop run-unload period is allowed for the
compressor to fully unload prior to shutdown.
Operation and diagnostics are discussed in detail in
sections 5 and 10.
External Base Loading
The chiller module (1U1) provides for external hard-
wired control of the chiller in a mode known as "base
loading."
Primarily for process control requirements, base
loading provides for immediate start and loading of a
chiller up to an externally or remotely adjustable
current limit setpoint without regard to differential to
start or stop, or to leaving water temperature control.
This allows the flexibility to prestart or preload a
chiller in anticipation of a large load application. It
also allows you to keep a chiller on line between
processes when leaving water temperature control
would normally cycle the unit.
This feature is controllable either through a Tracer
communication interface or a 4-20mA or 2-10VDC
hard-wired analog input (J7-11, J7-12) with a binary
input (J7-1, J7-2) for enable/disable. When the binary
input is closed, the base load function will be enabled
and the chiller will attempt to start (subject to all
normal safeties and interlocks. The chiller will then
load up to a current limit defined by the analog input.
a 2VDC or 4 mA input corresponds to a base load of
40% RLA and a 10 VDC or 20 mA input corresponds
to 100% RLA. Dip switch SW2-1 must be set ON for
4-20 mA operation.
Head Relief Request Contact
The options module (1U5) provides a contact closure
output (J12-1, J12-2) that may be used to control
indicating and/or auxiliary equipment in emergency
situations, to provide additional heat rejection
requirements. Note that this contact closes at an
extreme head condition and should not be used for
normal cycling of heat rejection equipment.
Installation, Operation and Maintenance
Tracer Controlled Contact
The options module (1U5) provides a Tracer-
controlled relay normally open contact closure output
(J18-1, J18-3) and normally closed contact output
(J18-2, J18-3). This feature can be used for any
customer-specified requirement, via programming
Tracer to energize this relay.
Ice Making Contact
The options module (1U5) provides a relay contact
closure output (J8-1, J8-2) that is energized any time
the UCP2 is in the ice making mode. This contact
can be used for any customer-specified logic such as
controlling valves and pumps and transition to normal
cooling after ice-making is complete.
Ice Machine Control
The options module (1U5) uses a dry contact input
(J3-7, J3-8) to enable the chiller in ice-making mode.
When this contact input is closed, the chiller will use
the evaporator return water temperature sensor input
and the active ice termination setpoint to determine if
ice making is required. Ice machine control must be
enabled in the UCP2 machine configuration group to
perform this function.
External Chilled Water Setpoint
The options module (1U5) will accept either a 2-10
VDC or a 4-20 mA input (J9-4, J9-5) signal, to adjust
the chilled water setpoint from a remote location. DIP
switch SW3-1 must be set to ON for 4-20 mA or OFF
for 2-10 VDC. The 2-10VDC or 4-20 mA input
corresponds to a 0-65 F chilled water setpoint range,
i.e. 2VDC or 4mA corresponds to 0 F and 10VDC or
20mA corresponds to 65°F.
Both external chilled water setpoint and current limit
setpoint must use the same input type. External
chilled water setpoint input must be installed and the
type selected in the UCP2 machine configuration
group.
External Current Limit Setpoint
The options module (1U5) will accept either a 2-
10VDC or a 4-20mA input (J7-11, J7-12) signal to
adjust the current limit setpoint from a remote
location. DIP switch SW2-1 must be set to ON for 4-
20mA or OFF for 2-10VDC. The 2-10VDC or 4-20mA
input corresponds to a 40-120 percent current limit
setpoint range i.e. 2VDC or 4 mA corresponds to 40
percent and 10VDC or 20mA corresponds to 120
percent.
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