How to Test an Air Flow Meter
Air flow meters are used for measuring the velocity of air in a contained system such as heating and air ducts. For professional results these air flow meters maybe required to be sent to a certified testing agency once a year. But for a quick check on the meter, you can perform a check involving your vehicle and test the air flow meter.
- Difficulty:
- Moderately Challenging
Instructions
Things You'll Need
- Air flow meter
- Car or truck
- Helper
- Open road for approximately a ¼ mile
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1
Understand that air flow meters utilize a small set of blades that catch the air and generate a voltage that in turn is read on a LCD or analog type meter. Generally these meters output a reading of airflow in "feet per minute". We can correlate this to the speed of a vehicle that travels at 10 MPH (miles per hour). Through a simple formula of dividing 52,800 feet (10 MPH) by 60 minutes (minutes in one hour) the result is 880 feet per minute. This airflow reading should be "close" to a vehicle traveling at a speedometer reading of 10 MPH.
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2
Start the vehicle and have a helper hold the air flow meter out of the passenger window after you have found an open section of road for approximately a ¼ mile.
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3
Set the vehicles speedometer to 10 MPH and have the helper switch the air flow meter "on" once the vehicle has reached a stable speed. Depending on obstructions of airflow from the vehicle itself, the air flow meter should be reading in the area of 880 feet per minute.
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4
Calculate other speeds to feet per minute by simply dividing the speed ratio of the vehicle by the standard set at 10 MPH. A vehicle traveling at 5MPH will give a reading of 440 feet per minute. A speed of 20 MPH will result in the airflow meter reading 1760 feet per minute.
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1
Tips & Warnings
Atmospheric wind speeds will play a factor in the testing of the airflow meter by the above method. This test should only be conducted on a calm day with little or no winds.
Follow all traffic rules and regulations when performing the above tests.
