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STEP 1.
Drill a 3/16" hole in the duct (ideally 3 feet downstream of
any elbows or bends and 1 foot upstream of any elbows
or bends) in the Fresh Air and Stale air streams.
Stale Air From Building
Balancing
Drill 3/16" holes in
Damper
Stale & Fresh Air
ducts.
Fresh Air to Building
Balancing Damper
STEP 3.
Repeat Step 2 to measure the Fresh Air to Building duct.
Pitot tube tip facing
towards the air stream.
Magnehelic Gauge
must be level.
STEP 2.
Insert the Pitot tube with the tip facing towards the air
stream in the Stale Air From Building air stream. Move
the Pitot tube around in the duct (facing towards the
airflow) and take an average reading. Record the reading.
Magnehelic Gauge must be level.
STEP 4.
B) Upon completion of balancing, seal
the holes (foil tape recommended).
A) Review the readings and damper down the duct with the
highest duct velocity pressure. Repeat Step 2 and Step 3
until both ducts show indentical readings. For this example,
the Fresh Air to Building air stream has the highest duct
velocity pressure.
Pitot tube tip facing
towards the air stream.
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