Honeywell T7047C - Manual (Page 7)

7 62-0179
T7047C,G,H REMOTE SPACE SENSORS
OPERATION AND CHECKOUT
Operation
The T7047C,G Remote Sensor control element is a
negative temperature coefficient (NTC) thermistor. As
the room temperature increases, the resistance of the
thermistor decreases.
The T7047H Remote Sensor control element is a
positive temperature coefficient (PTC) thermistor. As
the room temperature increases, the resistance of the
thermistor increases.
The change in the thermistor resistance causes the
motor, system logic panel, or system transmitter bridge
circuit to become unbalanced. As the electronic motor,
system logic panel or system transmitter circuits react to
rebalance the circuit, damper or valve movement, or
sequential staging of heating and/or cooling equipment
occurs.
Low Range Thermostat
Use caution when setting temperatures below 40°F
(5°C). A low temperature setpoint can result in
temperatures below freezing in areas distant from the
remote sensor.
Calibration
The T7047 Remote Space Sensor is accurately
calibrated at the factory. It cannot be field calibrated.
Checkout
Allow the T7047 Remote Space Sensor to stabilize to
ambient conditions before taking a resistance
measurement. Measure nominal resistance according
to the values described in the Specifications section.
Measure the sensor resistance in accordance with the
temperature curves. See Fig. 3 through 7.
Check operation of the complete control systems as
directed in the associated technical publications.