Sensor Installation; Slab Sensor Installation - heat-timer SMC Installation & Operation Manuals

SENSOR INSTALLATION

SLAB SENSOR INSTALLATION

(Used Only when Sensor Type is set to Slab)
• The supplied Slab Sensor is an integral part of the SMC
operation. It provides the SMC with the slab temperature
and detects precipitation. See "Slab Sensor Operation
Overview" on page 4.
• The Sensor consists of the following components:
○ The Brass Slab Sensor with 90 feet of cable
○ The Brass Sensor Base with a conduit hole
○ Dummy Plastic Plug (used to replace the slab sensor
during slab installation).
○ Brass mounting screws and O-ring.
• The Brass Slab sensor incorporates a slab temperature
sensor, a moisture detection sensor, a slab sensor heater,
and a sensor to measure the heater temperature.
• The slab temperature sensor measures the actual slab
temperature. The moisture detection sensor measures the
moisture connectivity of the precipitation. Both sensors are
used by the SMC snow melting logic.
• The slab sensor heater and its temperature sensor are
used to melt any precipitation that is in contact with the
Slab Sensor. However, its operation has no effect on the
slab temperature sensor or the control operation.
Slab Sensor Location Considerations
• When installed, the Slab Sensor must be level. Before the slab
installation, support the Sensor Base to level the Dummy Plastic Plug with
the finished grade.
• The Slab Sensor (HT #904200-00) should be placed in a location that
represents the temperature of the majority of the slab. It should be placed
away from any buildings, vents, or other heat sources. Also avoid placing
it in a sunny area when most of the slab is in shade, or vice versa.
• An exception to this later rule would be when the sensor location is
chosen to prevent snow or ice buildup in a known problem area.
• Run conduit from the sensor location to the panel to house the sensor
wires. This will ease servicing the sensor.
• If more than 90 feet of wire is needed to reach the control panel, install
a junction box along the way. (Up to 400 ft of 18 AWG 6-conductor wire
may be spliced to the supplied wire).
• After the concrete has cured, remove the plug and install the Slab Sensor
using the O-ring and screws provided.
• Do not pull all the sensor cable from the Sensor Base. Leave an
additional 6-12" of sensor cable in the socket Base to ease servicing the
sensor.
10
Slab Sensor
Dummy
Plastic Plug
Slab
Sensor
Sensor
Cable
Conduit
Hole
The slab sensor base and its conduit must
be installed before the slab installation.
that will adversely affect the
sensor's moisture detection
important to periodically clean
SMC Installation and Operation Manual
Sensor
Screws
O Ring
Sensor
Base
ALERT
WARNING
The Slab Sensor is located
outdoors and is likely to
become covered with dirt
sensitivity. Therefore, it is
the sensor surface.