Kewaunee Air Alert 300, Инструкция по установке и эксплуатации

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3.5 Calibration Notes
The two calibration methods are intended to give the installer two options for calibrating the alarm.
Using the alarm point capture method it is necessary to adjust the air velocity on the Fume Hood using a
mechanical damper ( or fan speed controller ) to the desired alarm point and this is sampled by the unit.
It is necessary to re-adjust the air velocity back to the normal operating value. This method produces a
very accurate alarm point at a fixed value. This method of calibration is ideal when the fan speed can be
adjusted to the low air alarm value.
The second method of two point capture is slightly more involved but does not require the fan speed to
be adjusted to the alarm point level, however the fan speed will need to be adjusted to give a higher
value sample.
For fan fail alarm point calibration single point calibration is ideal. It is recommended that the fan is set to
give an alarm velocity of 0.3 m/sec ( 60 fpm) minimum and 0.5 m/sec (100 fpm) maximum. This
considers a normal operating velocity of approximately 0.75 m/sec (150 fpm).
Using the two point capture method is ideal for low air alarm calibration where the alarm point is required
to indicate a low operating velocity
– typically 80% of the normal operating velocity. The normal velocity
calibration point should be the normal operating velocity and the high velocity calibration point should be
150% of the normal operating velocity. For example - a normal operating velocity of 150 fpm would give
a low calibration point of 150 fpm and a high calibration point of 225 fpm.
This would give a low air alarm point of 120 fpm.
Take time when measuring the air velocities for the calibration procedure to allow for the velocities across the
airflow sensor to stabilize. If the velocities are changing or are turbulent during the sampling period the alarm will
detect this and ask you to repeat the sample.