tekmar 654 Snow Melting Control Installation - Manual (Page 7)

7 of 44 © 2013 654_D - 06/13
Sensor Wiring
Notice: The temperature sensor (thermistor) is built into the
sensor enclosure.
Remove the screw and pull the front cover off the sensor
enclosure.
The outdoor sensor can either be mounted directly onto a
wall or a 2" x 4" electrical box. When the outdoor sensor is
wall mounted, the wiring should enter through the back or
bottom of the enclosure. Do not mount the outdoor sensor
with the conduit knockout facing upwards as rain could
enter the enclosure and damage the sensor. •
•
In order to prevent heat transmitted through the wall from
affecting the sensor reading, it may be necessary to install
an insulating barrier behind the enclosure.
The outdoor sensor should be mounted on a wall which best
represents the heat load on the building (a northern wall
for most buildings and a southern facing wall for buildings
with large south facing glass areas). The outdoor sensor
should not be exposed to heat sources such as ventilation
or window openings.
The outdoor sensor should be installed at an elevation above the
ground that will prevent accidental damage or tampering. •
•
•
Mounting the Outdoor Sensor -------------------------------------------------------------------------- --------------------------------------------------------------------------
Sensor with bottom
entry wiring Sensor with rear
entry wiring Sensor mounted
onto 2" x 4"
electrical box
Connect 18 AWG or similar wire to the two terminals provided in the enclo-
sure and run the wires from the outdoor sensor to the control. Do not run
the wires parallel to telephone or power cables. If the sensor wires are lo-
cated in an area with strong sources of electromagnetic interference (EMI),
shielded cable or twisted pair should be used or the wires can be run in
a grounded metal conduit. If using shielded cable, the shield wire should
be connected to the Com or Com Sen terminal on the control and not to
earth ground.
Follow the sensor testing instructions in this brochure and connect the
wires to the control.
Replace the front cover of the sensor enclosure. •
•
•
Wiring the Outdoor Sensor ----------------------------------------------------------------------------- -----------------------------------------------------------------------------
Mounting the Universal Sensor ------------------------------------------------------------------------- -------------------------------------------------------------------------
NOTICE: These sensors are designed to mount on a pipe or in a temperature
immersion well.
The Universal Sensor should be placed downstream of a pump or after an
elbow or similar fitting. This is especially important if large diameter pipes
are used as the thermal stratification within the pipe can result in erroneous
sensor readings. Proper sensor location requires that the fluid is thoroughly
mixed within the pipe before it reaches the sensor.
Strapped to Pipe
The Universal Sensor can be strapped directly to the pipe using the cable tie
provided. Insulation should be placed around the sensor to reduce the effect
of air currents on the sensor measurement.
Wires from outdoor
sensor to control’s
outdoor sensor and
sensor common
terminals
Sensor is built into
the enclosure