Measuring Velocity; Switching On The Power - Alnor 9870 Owner's Manual

Measuring velocity

For highest accuracy, it is important to properly
align the probe to the flow. The measured air must
flow through the sensor window at the end of the
probe.
HINT for measuring velocity: If the probe is left to
warm up for more than a few seconds at veloci-
ties below 50 fpm (0.25 meters/sec), it will
require more time to stabilize when it is inserted
into a higher flow. This is because the probe
assembly self heats at such low flows, and must
then re-stabilize when placed into higher flow.
For best response time at velocities of 100-200
fpm (0.5-1 meters/sec), it is recommended to first
place the probe into the flow, and then turn the
meter on.
When the meter is in the velocity mode the
temperature sensor will be warmed by heat from
the velocity sensor. If the meter is then switched to
temperature mode, it will read several degrees high
until the temperature sensor can cool. Therefore,
when you plan to measure both temperature and
velocity, it is best to measure temperature first.

Switching on the power

Turn on the Model 9870 using the ON/OFF switch.
It will display battery life for the first 5 seconds.
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