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Raychem-AR-H58692-ACS30UIT2Programming-EN-1805
Min Pipe Size:
Min. Pipe Size is the diameter of the smallest heat-traced pipe in the group controlled
by this circuit. Small diameter pipes heat up and cool down more rapidly than larger diameter pipe.
Therefore, the PASC duty cycle is calculated over a shorter time base. Larger diameter pipes heat and
cool less rapidly, so the on/off periods for the heater system can be stretched over a longer period.
If electromechanical contactors are being used to control the heater circuit, the longer time base
reduces the number of contactor on/off cycles and extends the contactor life.
Select:
0.5, 1,
≥
2 inches
Default:
0.5 inches
Maintain temperature setpoint:
Fixed design setpoint: 40°F (5°C)
Minimum Ambient: Enter the minimum ambient temperature for your installation:
Range:
-40°F (-40°C)–40°F (5°C)
Default: 30°F (-1°C)
Power Adjust:
This allows the PASC control to be adjusted when the heating cable output is greater
than the design assumption, or if the pipe insulation proves to be more efficient than assumed. Pipe
temperature may run higher or lower than desired if the heating cable has a different output than
required to offset the heat loss. The Power Adjust parameter enables a reduction or an increase in
the heating effective power by entering a value less or greater than 100%
Range: 10–200%
Default: 100%
IMPORTANT:
If improperly used, the Power Adjust parameter can cause the piping to get too
cold or too hot. If unsure, leave at 100%. Do not change this value unless an engineer calculates
the temperature impact on the system and determines that it is safe to do so. Be particularly
cautious if the circuit has more than one diameter of pipe or type of heat tracing. Contact a nVent
representative for assistance with this factor.
Fail Safe:
The Fail Safe control button turns the power on or off to the heating cable if the circuit
loses all valid RTDs.
When the last remaining sensor for control fails (or communication with the sensor is lost), the
ACS-UIT2:
•
Signals an alarm for the failure of the sensor
•
Changes control of the circuit to the fail safe control selected
•
Changes the control status display to indicate that control of the circuit is in the fail safe state
•
Records the events
When the sensor for control is returned to service, the ACS-30 controller signals the alarm has been
cleared, returns the circuit to its normal control mode, and records both of these events.
Range:
Power On or Power Off
Default:
Power On
External Override:
The dry contacts from a BMS system or external device may be assigned to the
circuit to de-energize the circuit to save power when it is not needed. All temperature and system
alarms are still active. Refer to Appendix 5.3 for further details.
