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28
JOHNSON CONTROLS
FORM 145.05-NOM2 (807)
STATIC PRESSURE TRANSDUCER INSTALLATION
(VAV UNITS ONLY)
All units provided with a VFD include a factory
mounted static pressure sensor (SPS1). The unit can
also have an optional second static pressure sensor,
(SPS2). The second static pressure transducer would
be used if the main supply duct split into two main
branches. The control can be programmed to maintain
the lowest input, highest input or the average of the two.
The sensor is factory wired and requires fi eld installation
of ¼” ID sensor tubing to the selected duct location. A
fi eld supplied static pressure probe and tubing must be
installed in the fi eld prior to unit start up.
Be sure that tubing complies with local
code requirements. Flame retardant
plastic or metal tubing may be re-
quired. Carefully select the ductwork
sensing point for the pressure sensor.
Improper location of the sensing point
will result in unsatisfactory opera-
tion of the entire variable air volume
system.
The following guidelines should be adhered to:
1. Plastic tubing (1/4” ID) must be run from the high
pressure tap of the duct static pressure transducer
to a static pressure tap (fi eld supplied) in the
supply duct. The static pressure probe should
be mounted two-thirds of the way down the duct
prior to any take off.
2. The sensing probe should be located in a non
turbulent fl ow area of the duct. Keep several
duct widths away from bends or neck downs.
Mounting Instructions
1. Drill a hole in the duct in a location per the above
guidelines and mount the fi eld supplied duct static
sensor.
2. Clamp a second tube (atmospheric reference)
to the outside of the duct at the location of the
sensing point.
3. Route both tubes along the ductwork and back to
the unit. The duct static transducer(s) are located
in a compartment above the blower compartment
on the right side of the unit.
4. Drill two holes through the unit upright post in the
vicinity of the transducer(s). Each of the tubes
should be routed through a grommet to protect
the tubing and seal the cabinet. The size of the
holes will vary based on the type of grommet
used.
5. Connect the tube from the duct static sensor to
the “high” port on the transducer and connect the
second tube (atmospheric reference) to the “low”
port on the transducer.
6. If the unit has two duct static transducers repeat
the above procedure for the second transducer.
To avoid confusion between “high”
and “low” tubing, it is recommended
that two different tubing colors be used
and that this information be recorded,
along with the sensing point location,
on the master building blueprints.
Installation
Содержание YSCD
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Страница 105: ...105 JOHNSON CONTROLS FORM 145 05 NOM2 807 LD13009 8 FIG 11 WIRING DIAGRAM POWER CIRCUIT ...
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Страница 107: ...107 JOHNSON CONTROLS FORM 145 05 NOM2 807 8 FIG 13 WIRING DIAGRAM EXPANSION CONTROL BOARD LD13011 ...