UMS T5 User Manual page 31

Service and maintenance
Check the T5
Zero offset:
Place the T5 flat on the table.
Put a drop of water on the cera-
mic cup.
Now the potential is zero and
the reading should be between
- 3 hPa and + 3 hPa (= -0.3 kPa
to +0.3 kPa).
To find out the maximum measuring range of this T5 hold the
ceramic tip in the headspace of the bottle over the water.
When you move the ceramic away from the water surface the air
gets dryer and the suction rises.
Hold the ceramic as close to the water surface so the tension
reading will rise slowly. Depending on the filling quality the value will
reach -85 to -450 kPa. Then, the value will rapidly drop to the vapour
pressure (around -90 kPa depending on the altitude). Then,
immediately put some water on the ceramic and cover the ceramic
with the protective bulb which should be filled with water to the half. It
will take one day until the Tensiometer will reach its initial value.
Check the response:
Open the bottle with the water.
Dry the ceramic surface with a
clean tissue.
Then wave the cup in the air.
The reading should rise to -80
kPa within 10 seconds.
If this is the case, the T5 is filled
perfectly.
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