Siemens SITRANS FUH1010PVDX, Operating Instructions Manual, Page: 90 / 308

3-20
CQO:1010PVXFM-3
Section 3
1012EC SERIES CABLE
THREADED PIPE FITTING
THERMOWELL
THERMAL COUPLANT
PIPE WALL
991TW TEMPERATURE SENSOR
CONNECTOR HEAD ASSEMBLY
SPRING LOADED
SENSING ELEMENT
991TW Thermowell Temperature Sensor
3.5 NOTES ON SYSTEM ANALOG INPUT MODULES
Dual Channel/Path Models
The Dual Channel/Path flowmeter uses T1 to report liquid temperature. (Note that T2 is used to
report ambient temperature in some Leak Detector systems.)
The Analog Input of temperature takes priority over the built-in RTD (Resistive Thermal Device)
measurement of temperature.
3.6 CLAMP-ON RESISTIVE TEMPERATURE DEVICE (RTD) INSTALLATION NOTES
The Clamp-On RTD sensor, with which your FUH1010PVX is supplied, is extremely sensitive and precise.
Its contribution to the performance of your meter can be as important as that of the liquid flow sensors.
Please consult the installation drawings for details on physical installation and wiring of the RTD. In order
to produce the best possible tracking of the true liquid temperature, try to make your installation conform
to the notes on the installation drawing and these following tips:
Prepare the pipe surface by removing paint to expose bare metal and by smoothing out any remain-
ing rough spots.
Use the thermal couplant compound (CC#117) between the face of the RTD element and the pipe
surface to improve the conductivity of the metal-to-metal contact.
Keep the RTD out of direct sunlight or other non-pipe sources of heat or cold that may affect their
temperature sensing. The foam insulator supplied helps in this regard, but consider using additional
pipe insulation for all installations exposed to extreme ambient conditions. Consider mounting the RTD
under the pipe in order to keep it out of direct sunlight.
In installations where RTD elements are exposed to harsh conditions such as condensation, salt spray,
etc., use CC#110 couplant compound to coat the connection between the cable and the RTD sensor.
Consult Installation Drawing 991TN-7 for details.