JOHNSON CONTROLS
82
FORM 145.05-NOM7
ISSUE DATE: 10/31/2019
SECTION 2 – INSTALLATION
SUPPLY
FAN VFD
CONTROL
COMPARTMENT
DUCT
STATIC
TRANSDUCER
LD14016
FIGURE 58 -
DUCT STATIC TRANSDUCER
LOCATION
STATIC PRESSURE TRANSDUCER
INSTALLATION (FLEXSYS
™
UNITS ONLY)
All FlexSys
™
units include a factory mounted static
pressure sensor (SPS1). The unit can also have an op
-
tional second static pressure sensor, (SPS2). The sec
-
ond static pressure sensor would be used to get an av-
erage of the static pressure in the under floor space.
When two static pressure sensors are used the control
can be programmed to maintain the lowest input, high-
est input, or the average of the two inputs. The sensors
are factory wired and require field installation of 1/4
inch ID sensor tubing to the selected under floor loca-
tion. A field supplied static pressure probe and tubing
must be field installed prior to the start up of the unit.
DUCT STATIC
TRANSDUCER 1
SUPPLY AIR
TEMPERATURE
DUCT STATIC
TRANSDUCER 2
(Optional, not shown)
HIGH DUCT
STATIC SAFETY
SWITCH
LD14416
FIGURE 59 -
DUCT STATIC TRANSDUCER LOCA-
TIONS
Check that tubing complies with local
code requirements. Flame retardant
plastic or metal tubing may be required.
Carefully select the ductwork sensing
point for the pressure sensor. Improper
location of the sensing point results in
unsatisfactory operation of the entire
variable air volume system.
Installation Instructions
1. Run the tubing from the duct static probe in the
underfloor space back to the unit. This tube should
be connected to the high port on the transducer.
2. A second tube must be run and positioned in an
area that provides an atmospheric reference to the
low side port of the transducer. This is particularly
critical on units where the equipment room is used
as the return.
3.
The duct static transducer(s), (see
) are located in the electric compart
-
ment. The tubing can be routed through a 7/8"
hole in the top of the control enclosure. Make
sure to use tie-wraps to keep the pneumatic tubing
away from the electrical components and wiring.