Velocity Measurement With The Control Unit - TESTO 300 XXL Instruction Manual

Special notes on the thermal velocity probe with
direction probe 0635.1041
Fully push down the cap of the probe.
During the measurement, observe the markings of the
probe head and on the telescope. The markings must form
a line.
For velocity measurements with a known
direction of flow, the arrow mark on the probe
head must point in the direction of flow.
For velocity measurements with an unknown
direction of flow, turn the probe 360° around its
axis. Observe the reading. The maximum value
indicates the direction of flow.
Note
Measurement against the direction of the arrow falsifies the
readings by up to 40%.
Example measurement
Velocity measurement
with the control unit
31