14
Trouble shooting guide
14.1
The measured value is flow dependent and too high (i.e. too hu-
mid)
Cause
Solution
The humidity measuring system
is still not stabilised, transient
process.
Wait for the stabilization time. If the measuring system was kept
unused for a longer time in ambient humidity, specially in deep
dew point values, the stabilisation time to be considered up to
even one hour for the measuring chamber and the sinter filter to
dry up. During this time, compressed air must keep flowing
through the measuring chamber
The probe line is leaking to
environment.
Seal up faulty points.
Unsuitable measuring line of
plastic.
Use Teflon line.
There is condensed water in the
measuring chamber or in a
fitment thread.
Dry up Components, let the air divert off, wait for stabilization
time.
There is condensed water in the
system, the lines have not yet
dried up after a fault.
After a dryer malfunction, the drying process can take several
days. First carry out test measurements as near as possible after
the dryer!
14.2
The measured value is too high (i.e. too humid)
Cause
Solution
Filter choked, transient time is
too high.
Return the measuring probe to manufacturer for filter
replacement .
Sensor oil covered.
Return the measuring probe to manufacturer for repair.
There is condensed water in a
branch line of the distribution
network. In such a case, the
humidity will continuously rise,
specially with low air
consumption (for example during
the night).
This behaviour is being considered as "Normal" in many plants.
After a malfunction with visible condensed water, it lasts for a
very long time, until all branch lines(without flow) are drained
again. This particularly applies to branch lines at cold places. En-
force air removal on rarely used branch lines (i.e. let the air get
diverted) to drain the line segment.
Capillary tube of measuring
chamber choked.
Replace measuring chamber.
