nvent 910 Series Installation, Operating And Maintenance Instructions page 32

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IMPORTANT:
• If the EXTERNAL INPUT is not configured as either INHIBIT or FORCE ON then OVERRIDE
SOURCE will always automatically be set to REMOTE. See Section 5-3-3 for further details.
• If the autocycle feature is enabled, it will continue to function even when an INHIBIT override
signal is being received as long as load shedding is not active.
• Fail safe mode is inactive if an INHIBIT override signal is being received.
• Load shedding and fail safe modes are inactive if a FORCE ON override signal is being received.
• Only the LOW TS ALARMS for temperature sensors used by the TS CONTROL MODE are
inactive if an INHIBIT override signal is being received.
5.2.22 LOAD SHEDDING ENABLING
Purpose: The load shedding function allows the controller output to be forced OFF by way of a
remote contact input on the 780 Group Communications Controller or using the communications
port and an upstream device. It may be used to turn OFF the output of one or more controllers
in order to reduce energy consumption to avoid peak demand surcharges, remove power from
unused circuits, or remove power from circuits which may be subjected to steam cleaning.
Setting: ENABLE or DISABLE
Procedure: Enable or disable the load shedding control mode as desired.
IMPORTANT: To completely configure the HTC for load shedding operation, the following
additional parameters must be set up using the Model 780/GCC-9000:
Fail Safe Mode
Load Shedding GCC Contact Association
These additional parameters may only be accessed using the Group Communications
Controller. See the appropriate Section of the GCC manual for further details.
IMPORTANT:
• Fail safe mode is not supported when using proportional ambient SSR or proportional
ambient contactor modes.
• For fail safe mode to function, at least one LOW TS ALARM of the controlling temperature
sensor(s) must be enabled and the corresponding LOW TS ALARM temperature setting must
be less than the CONTROL SETPOINT temperature.
5.2.23 CONSOLE SETPOINT MAXIMUM
Purpose: When using the Operator Console the maximum setting of the CONTROL SETPOINT
temperature may be limited to the CONSOLE SETPOINT MAXIMUM value. This is a safety
feature to prevent users in the field from modifying the CONTROL SETPOINT temperature
setting to a dangerous level.
Range: –76°F to 1058°F (–60°C to 570°C)
Procedure: Adjust the CONSOLE SETPOINT MAXIMUM temperature value to limit the maximum
allowable CONTROL SETPOINT TEMPERATURE that may be set using the Operator Console.
The CONSOLE SETPOINT MAXIMUM may only be set using a communicating device such as
the Model 780/GCC-9000. See the 780/GCC-9000 user manual for the proper procedure.
IMPORTANT: The CONSOLE SETPOINT MAXIMUM is not displayed on the Operator Console.
5.2.24 CONSOLE SETPOINT MINIMUM
Purpose: When using the Operator Console the minimum setting of the CONTROL SETPOINT
temperature may be limited to the CONSOLE SETPOINT MINIMUM value. This is a safety
feature to prevent users in the field from modifying the CONTROL SETPOINT temperature
setting to a dangerous level.
Range: –76°F to 1058°F (–60°C to 570°C)
Procedure: Adjust the CONSOLE SETPOINT MINIMUM temperature value to limit the minimum
allowable CONTROL SETPOINT TEMPERATURE that may be set using the Operator Console.
The CONSOLE SETPOINT MINIMUM may only be set using a communicating device such as
the Model 780/GCC-9000. See the 780/GCC-9000 manual for the proper procedure.
IMPORTANT: The CONSOLE SETPOINT MINIMUM is not displayed on the Operator Console.