Summit Ice Melt Systems
PO Box 6928, Tahoe City, CA 96145
Ph: 530-583-8888
summiticemelt.com
Multi-Circuit Ambient Temp Sensing Digital Controllers
Operation
The Multi-Circuit Controller uses a thermistor to sense ambient temperatures. When the
temperature drops below the Heater-On set-point, the system is energized. When the
temperature rises above the Heater-On set-point, the system is de-energized.
If the temperature drops below the low-temp cutoff, the system is de-energized. When
the temperature rises above the low-temp cutoff, the system is energized.
The 3-position rocker switch allows the operator to set the system in Automatic,
Manual, or Off mode (center position). When the rocker switch is set to the MANUAL
position, heaters are energized, regardless of ambient conditions.
Installation
The Multi-Circuit Controller enclosures vary in size to accommodate the number of
circuits controlled. The enclosures are NEMA 4/12 rating so they may be mounted
indoors or outdoors, typically near the circuit breaker panel. Each branch circuit must be
protected by a ground fault protection device per the NEC. A 120Vac protected circuit is
required to energize the controller.
The ambient sensor is mounted outdoors in a shaded location representative of
minimum ambient conditions (typically on the north side of a building), and away from
any heat source, such as direct sunlight or a utility room exhaust vent, so that the
temperature sensor gives an accurate reading of the air temperature reflective of actual
ambient conditions. The ambient sensor comes with a standard 10 ft lead, but its range
can be extended up to hundreds of feet using ordinary stranded copper wire. See
schematic diagram for details.
Pre-Season Testing
The heater circuits may be energized and tested for proper functionality prior to the cold
weather season by simply setting the 3-position rocker switch to Manual. Amperage
readings may then be taken on each branch circuit. Amperage will depend on ambient
temperature and time. Follow heater manufacturer test procedures.
