Installation Problems
The following is a summary listing of problems that may be encountered
with the installation of the MTI10/MTL10 Thermal Mass Flowmeter.
1.
Improper wiring connections for power and/or 4 to 20mA output
signal.
The MTI10/MTL10 require a separate power source for the main
board and the two 4 to 20mA output signals. Two wires supply
24VDC power to the main board. Two wires are used for each of the
4 to 20mA output signals. Refer to Figure 3.4 (p. 19) and Figure
3.5 (p. 20). Also refer to "Wiring Precautions" and "Helpful Hints"
in Wiring section (p. 15) for further guidance.
2.
Inadequate power source.
For those models that are powered by 24VDC, a 24VDC ±10%,
0.75 amp or greater power supply is recommended. If the voltage
supplied is not within this range or if the power supply is not rated
for 25 watts minimum, a variety of problems can occur including
inaccurate flow readings, dim display and faulty programming action.
The input voltage must be within the range of 23 to 25VDC as
measured at the power input terminals of the flowmeter electronics.
3.
Flow measurement seems inaccurate.
•
Check to ensure that the flowmeter is installed so that the Flow
Direction Arrow engraved on the flat surface of the fitting below
the electronics housing is properly pointing in the direction of
flow. Refer to Figure 2.7 (p. 14). If not, change orientation of
meter.
•
If you have a MTI10 insertion type flowmeter, check that the
insertion depth of the sensor/probe is correct. The end of the
probe should be adjusted as per Figure 2.2 (p. 10).
•
For inline meter types, ensure that there are a minimum of
ten diameters of straight pipe upstream of the sensor and five
diameters downstream (¼" meters: 6” [152 mm] of straight,
unobstructed pipe upstream and downstream required). For
insertion meter types, ensure that there are a minimum of
fifteen diameters of straight pipe upstream of the sensor and
ten diameters downstream. If complex flow disturbances are
upstream of the sensor, extension of the straight pipe may be
required to ensure accurate flow measurement. Contact Spirax
Sarco for assistance.
• Ensure that pipe area data in the meter matches data on the
Spirax Sarco Calibration Certificate. The pipe internal cross
sectional area is programmed into the flowmeter through
the front panel (see Flow Parameters, p. 42). This area is
programmed in square feet or square meters. The Calibration
Certificate delivered with the flowmeter contains the area that
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100
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Troubleshooting: Installation Problems
Problem Summary
Troubleshooting: Installation Problems