tekmar 076 Indoor Sensor - Manual (Page 2)

© 2007 D 076 - 05/07 2 of 4
A good quality test meter capable of measuring up to 5,000 kΩ (1 kΩ = 1000Ω) is required to
measure the sensor resistance. In addition to this, the actual temperature must be measured
with either a good quality digital thermometer, or if a thermometer is not available, a second
sensor can be placed alongside the one to be tested and the readings compared.
First measure the temperature using the thermometer and then measure the resistance of
the sensor at the control. The wires from the sensor must not be connected to the control
while the test is performed. Using the chart on the following page, estimate the temperature
measured by the sensor. The sensor and thermometer readings should be close. If the test
meter reads a very high resistance, there may be a broken wire, a poor wiring connection
or a defective sensor. If the resistance is very low, the wiring may be shorted, there may be
moisture in the sensor or the sensor may be defective. To test for a defective sensor, measure
the resistance directly at the sensor location.
Do not apply voltage to a sensor at any time as damage to the sensor may result.
Sensor Testing Instructions
STEP FOUR
WIRING THE INDOOR SENSOR
Run two conductor 18 AWG or similar wire between the Indoor Sensor and the terminals
on the tekmar control. Insert the wires through the hole provided in the back of the indoor
sensor enclosure and connect them to the indoor sensor terminal block. Do not run the wires
parallel to telephone or power lines. If the indoor sensor wires are located in an area with
strong sources of electromagnetic noise, shielded cable or twisted pair should be used or
the wires can be run in a grounded metal conduit. If using shielded cable, one end of the
shield wire should be connected to the Com-Sen terminals on the control and the other end
should remain free. The shield must not be connected to earth ground. Follow the sensor
testing instructions below and connect the wires to the control.
STEP FIVE
INSTALLING THE FRONT COVER
The Indoor Sensor 076 front cover is installed by aligning the hinges on the bottom of the
front cover with the bottom of the sensor mounting base. The front cover is then pivoted
around the bottom hinge and pushed against the mounting base until it snaps firmly into
place.