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882108-YIM-B-1012
20 Johnson Controls Unitary Products
STATIC PRESSURE CONTROL PLASTIC TUBING
On units with variable frequency drives (VFD’s) or inlet guide
vanes (IGV's) on the supply blower and/or power exhaust
fans, pressure sensing tubing must be field supplied and
installed. All tubing must be installed from the transducers
(located in the unit) to the location in the building (or
ductwork) where a constant pressure is desired. The tubing
must also be installed from the transducers to a low-side ref-
erence to the atmosphere.
The supply air duct pressure sensor (DPS) is located in the
control box directly below the Millennium Simplicity® control.
Plastic tubing (1/4”) must be run from the high pressure tap of
the transducer to a static pressure tap (field supplied) in the
supply duct located at a point where constant pressure is
desired. Tubing must also be run between the low pressure
tap of the transducer to atmospheric pressure. Changing the
adjustment is done to the duct pressure setpoint in the con-
trol.
EXHAUST STATIC PRESSURE
If a modulating-damper or variable frequency drive power
exhaust is installed, there will be a building pressure sensor
(BPS) in the control box directly below the Millennium Sim-
plicity® control. This ± .25 0-5VDC transducer sends a build-
ing pressure signal to the control. A sensing tube must be
installed from a representative location in the building to the
HI port of the transducer. Tubing must also be run between
the low pressure tap of the transducer to atmospheric pres-
sure.
Changing the adjustment is done to the building pressure set-
point in the control.
Do not run plastic tubes in the supply or return air
ducts as air movement could cause erroneous
sensing. If tubes penetrate bottom of unit be sure
openings are sealed against air and water leak-
age.