9
JOHNSON CONTROLS
FORM 100.50-EG12 (918)
On/Off Powered Exhaust
–
This option provides simple building pressure control. It can
be controlled via a building pressure signal, or via outside air damper control.
This option
is not available for VAV units
.
Modulating Powered Exhaust with Damper Control –
This option consists of a con-
stant-speed exhaust fan with a discharge damper that is modulated to control the flow
of exhaust air. The damper control logic is based on the building static pressure setpoint
within the single package unit controller. The static pressure transducer is provided in
the return plenum of the single package unit, and 5/16-inch or 1/4-inch plastic tubing and
static pressure sensor must be supplied by others and installed in a representative loca-
tion in the building.
Modulating Powered Exhaust with a VFD
– This option consists of a VFD to modulate the
speed of the exhaust fan to control the flow of exhaust air. The VFD control logic is based
on the building static pressure setpoint within the single package unit controller. The static
pressure transducer is provided in the return plenum of the single package unit, and 5/16-
inch or 1/4-inch plastic tubing and static pressure sensor must be supplied by others and
installed in a representative location in the building.
Powered Return Fan with Exhaust
– This option uses single width, single inlet (SWSI)
plenum fan(s) to control building pressure. The fan motors are driven by a VFD to maintain
a constant return plenum pressure. An exhaust hood with a modulating control damper
is used to maintain building pressure via the building static pressure. The static pressure
transducer is provided in the return plenum of the single package unit, and 5/16-inch or
1/4-inch plastic tubing and static pressure sensor must be supplied by others and installed
in a representative location in the building. The powered return fan is also available with-
out the exhaust capabilities. For units with no exhaust capabilities, the HVAC system must
provide alternate means of controlling building pressure.
SUPPLY FAN OPTIONS
Double Width, Double Inlet (DWDI) Forward-Curved Supply Fan –
The standard sup-
ply air blower in the YPAL070–80 models is a forward-curved supply fan. This fan is good
for medium static pressures and high airflows.
DWDI Airfoil Supply Fan
–
The standard supply air blower in the YPAL090–105 is an
airfoil blade supply fan. This fan is also available as an option on YPAL070–080 for higher
static conditions. This fan offers higher efficiency and lower sound in certain applications.
Fan Skid Isolation –
The entire supply fan assembly is isolated from the unit base with
one- (standard) or two-inch deflection springs, or one (standard) or two-inch deflection
springs with seismic restraints.
Supply and Exhaust Fan Motors –
Premium efficiency ODP and premium efficiency
TEFC motors are available all meeting the Energy Policy Act of 1992 (EPACT).
Supply Fan VFD and Manual Bypass –
For VAV applications, VFDs are provided to
modulate airflow. Optional manual bypass can also be provided to allow full airflow in the
event of a VFD failure.
Direct Drive Plenum (DDP) Fan
– A direct drive plenum (DDP) supply fan provides out-
standing reliability and efficiency, eliminating the possibility of conditioned air supply inter-
ruption due to a broken belt and the pollution of conditioned air with belt dust. The supply
fan can be optionally equipped with a piezo ring to precisely measure the amount of air
delivered to the conditioned space. The speed of the supply fan is controlled by a VFD.