Daikin PreciseLine Series Installation And Maintenance Manual page 47

Figure 79: Air Flow Switch and Sensing Probe Locations
Figure 80: Sensor Terminals
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Duct Pressure Taps
Units that the fan will control to a duct static pressure require
a reading, which requires that pressure taps be field installed
and plumbed back to the pressure sensors in the unit. When
required, these sensors will be field installed.
Carefully locate and install the field provided pressure
tap. Improperly locating or installing the tap may cause
unsatisfactory operation of the building VAV system.
Consider the following pressure tap location and installation
recommendations. The installation must comply with all
applicable local code requirements.
1. Install a tee fitting with a leak-tight removable cap in each
tube near the sensor fitting. This facilitates connecting a
manometer or pressure gauge if testing is required.
2. Differentiate between the duct pressure (HI) and
reference pressure (LO) taps by using different
color tubing or by tagging the tubes. Daikin Applied
recommends 3/16ʺ I.D. plastic tubing.
3. Locate the duct pressure (HI) tap near the end of a long
duct to ensure that all terminal box take-offs along the
run have adequate static pressure.
4. Locate the duct pressure tap in a non-turbulent flow area
of the duct. Keep it several duct diameters away from
take-off points, bends, neckdowns, attenuators, vanes, or
other irregularities that may create turbulent air flow.
5. Use a static pressure tip or the bare end of the plastic
tubing for the duct tap. (If the duct is lined inside, use a
static pressure tip device.)
6. Install the pressure tap so that it senses only static
pressure (not velocity pressure). If a bare tube end is
used, it must be smooth, square (not cut at an angle) and
perpendicular to the airstream.
7. Locate the reference pressure (LO) tap somewhere near
the duct pressure tap within the building.
8. If the reference pressure tap is not connected to the
sensor, unsatisfactory operation will result.
47 IM 1267-7 • PRECISELINE AIR HANDLER
Installation