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Installation Electrical
Table 25. Programable Relays
LLID Name
Operating Status
Programmable Relays
Emergency Stop
The Symbio800 provides auxiliary control for a customer specified/installed latching trip out.
When this customer-furnished remote contact is provided, the chiller will run normally when the
contact is closed. When the contact opens, the unit will trip off on a manually resettable diagnos-
tic. This condition requires manual reset at the chiller switch on the front of the control panel.
External Auto/Stop
If the unit requires the external Auto/Stop function, the installer must provide leads from the
remote contacts to the proper terminals of the LLID on the control panel.
The chiller will run normally when the contacts are closed. When the contact opens, the compres-
sor(s), if operating, will go to the RUN:UNLOAD operating mode and cycle off. Unit operation
will be inhibited. Re-closure of the contacts will permit the unit to automatically return to normal
operation.
Note: A "panic" stop (similar to "emergency" stop) can be manually commanded by pressing
Soft Loading
Soft loading will prevent the chiller from going to full capacity during the pulldown period.
The Symbio800 control system has two soft loading algorithms running all of the time. They are
capacity control soft loading and current limit soft loading. These algorithms introduce the use of
a Filtered Chilled Water Setpoint and a Filtered Current Limit Setpoint. After the compressor has
been started, the starting point of the filtered chilled water setpoint is initialized to the value of
the Evap Leaving Water Temperature. The filtered current limit setpoint is initialized to the value
of the Current Limit Softload Starting Percent. These filtered setpoints allow for a stable pull-
down that is user adjustable in duration.
They also eliminate sudden transients due to setpoint changes during normal chiller operation.
Three settings are used to describe the behavior of soft loading. The setup for softloading can be
done using TU.
•
•
•
External Base Loading - Optional
Primarily for process control requirements, base loading provides for immediate start and load-
ing 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.
76
LLID Software
Relay Designa-
tion
Relay 0
Relay 1
Relay 2
Relay 3
the STOP button twice in a row, the chiller will immediately shut down, but without creat-
ing a latching diagnostic.
Capacity Control Softload Time: This setting controls the time constant of the Filtered Chilled
Water Setpoint. It is settable between 0 and 120 min.
Current Limit Control Softload Time: This Setting controls the time constant of the Filtered
Current Limit Setpoint. It is settable between 0 and 120 minutes.
Current Limit Softload Starting Percent: This setting controls the starting point of the Filtered
Current Limit Setpoint. It is adjustable from 40 to 100 percent RLA.
Output Name
Status Relay 4, J2-1,2,3
Status Relay 3, J2-4,5,6
Status Relay 2, J2-7,8,9
Status Relay 1, J2-10,11,12
Default
Head Pressure Relief Request
Chiller Limit Mode Relay
Chiller Alarm Relay
(latching or nonlatching)
Compressor Running Relay
RTHD-SVX04K-EN
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