Design Guide for Hazardous / Industrial
Self-regulating trace heating systems
21-1S00-7D0001/-
05/2023-EHT-466853
Notice Technical data subject to change without notice.
No claims for damage arising from alternations, errors or misprints shall be allowed.
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Ambient sensing control
Ambient sensing control:
uses an on-off thermostat that senses ambient temperature
is more energy efficient than self-regulating control because
the heating circuit is energized only when the temperature
drops below the set-point
is most suitable for freeze-protection applications where
multiple circuits can be controlled by a single sensing point
flow path considerations (flowing or non-flowing) are not re-
quired with ambient control.
Line sensing control
Line sensing control:
regulates the desired maintain temperature by turning the
heating circuit on if the pipe temperature falls below the set-
point and turning it off if it exceeds the set-point
the most energy-efficient method for controlling heat tracing
is a line-sensing thermostat, because a flowing pipe will
typically not need any additional heat to keep it at the
proper temperature
needs a separate circuit controlled by a line-sensing ther-
mostat for each flow path
where a piping system has tees and therefore multiple flow
paths, more than one thermostat may be required.
NOTICE
Line sensing provides tighter temperature control than ambient sensing but flow paths may require additional controllers.
Line temperature sensor
Ambient temperature sensor
Line temperature sensor
