CFM-88L 07/20/091
1.0 INTRODUCTION
1.1 GENERAL DISCUSSION
These instructions will be much easier to follow if the meter is in front of you as you read through them. You can note the
various connections and press the keys, observing the displayed results as you read through the various procedures. The
operation of the meter is quite simple and straightforward, as will become apparent after a little practice.
The CFM-88L AirData FlowMeter performs the following essential functions. When used with the Series 8400 FlowHood
Kit, this meter measures air flow and compensates for air density and backpressure effects, allowing direct air flow readings.
Temperature and absolute pressure measurements can be taken over a wide range.
The AirData FlowMeter and the AirData Multimeter automatically correct for air density variations due to local barometric
pressure. The meter also automatically corrects for the density effect of temperature if the TemProbe is connected. These
meters also may be used to compensate for the backpressure effect which occurs when any capture hood is placed over an
outlet. These capabilities eliminate several possible error factors, and the time consuming calculations normally necessary
to convert the air flow readings to local density results.
Internal calibration and zeroing of the AirData FlowMeter are fully automatic. No external adjustments are ever needed. This
instrument is extremely tolerant of overpressure, and is unaffected by position or ambient temperatures from 40
/F to 140/F.
NOTE: The FlowHood may require the development and use of correction factors when used on swirl diffusers, or on other
types of diffusers with uneven air throw. The FlowHood may not be appropriate for use on small supply outlets at high jet
velocities or “nozzle” type outlets. These outlets cause an extreme concentration of air velocity on portions of the flow sensing
grid. The FlowHood readings may be inaccurate under such conditions.
Consideration must be given to other system components, such as may be encountered on some single supply air outlet
applications, where the FlowHood's slight backpressure may directly affect fan performance, or where the FlowHood's
backpressure correction function may be affected by immediate response from a volume control box or air valve.
It is recommended that the AirData FlowMeter be returned to the factory at least every two years for recalibration and software
update. This preventive maintenance program will assure that the original accuracy of the meter is maintained throughout
the life of the meter.
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