Brochure

Possible cause What to examine How to find the error
The catalogue curve does not
reflect the 0-series test.
Compare O-series test with
catalogue curve.
If the catalogue curve and 0-series
test do not correspond, it can not
be expected that the pump performs
according to the catalogue curve.
Increased hydraulic friction
Compare the QH curves at the same
speed. Is the difference developing
as a parabola with the flow, there
could be an increased friction loss.
Examine surface roughness and
inlet conditions.
Remove irregularities in the
surface. Reduce surface roughness.
Remove elements which block
the inlet.
Calculation of the head is not
done correctly.
Examine the information about pipe
diameter and the location of the
pressure transducers. Examine
whether the correct density has been
used for calculation of the head.
Repeat the calculation of the head.
Error in the differential pressure
measurement.
Read the test bed’s calibration report.
Examine whether the pressure
outlets and the connections to the
pressure transducers have been bleed.
Examine that the pressure transducers
can measure in the pressure range
in question.
If it has been more than a year
since the pump has been
calibrated, it must be calibrated
now. Use the right pressure
transducers.
Cavitation
Examine whether there is
sufficient pressure at the pump’s
inlet. See section 2.10 and 6.3)
Increase the system pressure.
120
Table 3: The power consumption is as the catalogue curve but the head is too low.
B. Check of test results