Step By Step Operation - vectus ALNOR Balometer Jr. Manuel Du Propriétaire

Step By Step Operation

If the instrument has been stored at a temperature below 68°F (20°C) or
higher than 86°F (30°C) it should be allowed to stabilize at room
conditions (68°F to 86°F) in order to achieve specified accuracy.
1. Assemble the Balometer Jr. as described in the Preparation for Use
section of this manual.
2. Check the Velometer Jr. for zero adjustment by setting the range
selector to the 0 (OFF) position and verifying that the meter reads
zero. If necessary, use a small screwdriver to adjust the zero screw so
that the pointer reads zero. Although the meter will typically
continue to read zero (within one division) regardless of how the unit
is held, it is best to zero the meter in the position in which it will be
used.
3. Set the range selector to the highest range in the desired direction,
supply or return.
4. Bring the Balometer Jr. into contact with the perimeter of the diffuser
or grill to be measured. To assure maximum accuracy, the foam
gasket along the top of the frame must be firmly in contact with the
surface all around the opening. Take care to ensure that your body or
other material is not accidentally affecting the reading by blocking or
diverting the air flow at either the air entry or exit sides.
When using the Balometer Jr. to check air flow at ceiling diffusers,
make certain you can safely raise and hold the unit while making the
measurement. This is especially important when working on a
ladder. Make sure that the unit cannot be caught in moving
machinery.
5. If the reading is found to be below the full scale of the next lower
scale, the range selector may be switched to the next lower scale.
If the lowest (blue) scale is used, the Lo-Flow adapter screen must
be installed. See Preparation for Use section.
6. The reading from the Balometer Jr. is in cubic feet per minute or
cubic meters per hour, referenced to standard conditions of air
pressure and temperature (scfm or scmh). These standard conditions
are 70°F and 29.92 inches of mercury (21°C and 760 mm Hg). To
determine the true volume flow rate, multiply by the correction
factor shown in Figure 11. The correction factor is based on the static
pressure and air temperature at the manifold.
7. The additional system back pressure generated by the Balometer Jr.
may affect the output of an individual diffuser. Depending on system
design and balancing method, this may or may not be important.
When proportionally balancing a system of similar outlets, this is not
usually an important factor. If system design or other factors require
adjustment, Figure 12 is included for your reference.
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