Section 3 - Operational Notes - Omega HHF142 User Manual

SECTION 3 - OPERATIONAL NOTES

Caution: Do not attempt to measure flow from a duct that is smaller than the
diameter of the probe head that you are using. This will cause a false reading.
Follow the minimum duct cross-section guidelines as detailed below:
2. 7 5 inch Air Probe:
1 Inch Air Probe:
9009 -
Out of Range Error: There are a few circumstances which will cause
the instrument to display
1. Duct dimension is too small: If one of the user-entered duct
dimensions is smaller than the probe diameter as described above, the
instrument will display the out-of-range error.
2. Duct cross-sectional area is too large: If the cross-sectional area of
the duct is too large, the instrument will not be able to display a
meaningful result. The out-of-range error will be displayed. The
maximum duct cross-sectional areas are as follows:
2
a. 35 ft ( 3 . 2 5 m
( C FM)
2
b. 20 ft ( 1 . 8 6 m
(CMH)
Volume flow rate is too high: If the calculated volumetric flow rate is
3.
higher than 9999 cubic feet per minute ( C FM) or 9999 cubic meters per
hour ( C MH) the result cannot be displayed by the instrument. The out­
of-range error is displayed.
Minimum duct width of2. 7 inches ( 6 9 cm)
Minimum duct height of2. 7 inches ( 6 9 cm)
Minimum duct diameter of 2. 7 inches ( 6 9 cm)
Minimum duct width of 1.0 inches ( 2 . 7 cm)
Minimum duct height of 1. 0 inches ( 2 . 7 cm)
Minimum duct diameter of 1. 0 inches ( 2 . 7 cm)
9009,
which is the out-of-range er
2
when displaying in cubic feet per minute
)
2
) when displaying in cubic meters per hour
r
or. They are:
Rev 1.9, 10-Jun-2008
Page 13 of28