Fan Powered Variable Volume Terminal uniTs
15
priceindustries.com | FAn Powered VArIAbLe VoLume TermInAL unITs - manual
PNEUMATIC CALIBRATION PROCEDURES
1. Gauge taps are normally supplied
with the pneumatic controls to allow
field measurement of the differential
pressure at the sensor with a
manometer, magnahelic or other
measuring device.
If the terminal velocity controls
utilize a flow-through transducer,
a proper velocity pressure reading
will NOT be read at the gauge taps
and the calibration curves CANNOT
be used for field measurement. The
flow-through transducer operates
on the principle of mass flow rather
than pressure differential.
Controls utilizing a dead-ended
pressure transducer will allow field
measurement with the gauge taps
and calibration curves provided.
2. Setting flow limits for a differential
pressure of less than 0.02 inches
in NOT recommended. Stability
and accuracy of flow limits may not
be acceptable due to low velocity
pressure signal. Performance will
vary depending on the terminal unit
controls provided.
3. For field calibration of air flow limits
refer to the control contractor’s
documentation.
Calibration Equation
VP
- differential pressure at
sensor, inches w.g.
Q
- air flow rate, cfm at standard density.
K
- calibration constant
Unit Size
K
6
468
8
890
10
1487
12
2141
14
3045
16
4074
( )
K
2
VP = Q
FPV, FeV, FdV Calibration Curves