Dynasonics TFX Ultra Transit Time Flow Meters - Manual (Page 34)

HEAT FLOW FOR ENERGY MODELS ONLY
The energy version allows the integration of two 1000 Ohm,
platinum RTDs with the flow meter, effectively providing an
instrument for measuring energy consumed in liquid heating
and cooling systems. If RTDs were ordered with the energy
version of the flow meter, they have been factory calibrated
and are shipped with the meter.
The energy meter has multiple heat ranges to choose
from. For best resolution use the temperature range that
encompasses the temperature range of the application.
The three-wire surface mount RTDs are attached at the
factory to a simple plug-in connector eliminating the
possibility of mis-wiring. Simply install the RTDs on or in the
pipe as recommended, and then plug the RTDs into the RTD
connector in the flow meter.
Four ranges of surface mount RTDs and two lengths of
wetted insertion probes are offered. Other cable lengths for
surface mount RTDs are available. Contact the manufacturer
for additional offerings.
All RTDs are 1000 Ohm platinum, three-wire devices. The
surface mount versions are available in standard lengths
of 20 feet (6 meters), 50 feet (15 meters) and 100 feet (30
meters) of attached shielded cable.
Installation of Surface Mounted RTD’S
Surface mount RTDs should only be utilized on well insulated
pipe. If the area where the RTD is located is not insulated,
inconsistent temperature readings will result. Insertion
(wetted) RTDs should be used on pipes that are not insulated.
Select areas on the supply and return pipes where the RTDs
will be mounted. Remove or peel back the insulation all the
way around the pipe in the installation area. Clean an area
slightly larger than the RTD down to bare metal on the pipe.
Place a small amount of heat sink compound on the pipe in
the RTD installation location. See Figure 3.12. Press the RTD
firmly into the compound. Fasten the RTD to the pipe with
the included stretch tape.
Route the RTD cables back to the flow meter and secure
the cable so that it will not be pulled on or abraded
inadvertently. Replace the insulation on the pipe, ensuring
that the RTDs are not exposed to air currents.
S U PPL Y L IN E
R TD # 1
R ETU R N L IN E
R TD # 2
B A C K OF
C ON N EC TOR
Figure 33: RTD schematic
MINCO
Clean RTD Mounting
Area to Bare Metal Surface
Heat Sink
Compound
Heat Tape
Figure 34: Surface mount RTD installation
HEAT FLOW FOR ENERGY MODELS ONLY
Page 34 March 2014