24
Packaged and Split Rooftop Ventilator
© 2021 Mitsubishi Electric US, Inc.
Premi
Sys
Aluminum Energy Wheel
Available options are:
1. Modulating wheel frost control
2. Modulating wheel with electric preheat frost control
These options are provided with a temperature sensor
mounted in the exhaust air discharge compartment.
Frost control will initiate when the exhaust air
temperature is below 36°F.
Modulating wheel frost control includes a variable
frequency drive (VFD) in addition to the exhaust air
temperature sensor. When frost control is initiated,
the VFD will modulate the wheel speed to maintain
36°F exhaust air temperature. The VFD will be fully
programmed at the factory.
Modulating wheel with electric preheat frost control
includes a variable frequency drive (VFD) and electric
heater (at outdoor air intake) in addition to the exhaust
air temperature sensor. When frost control is initiated,
the VFD will modulate the wheel speed to maintain 36°F
exhaust air temperature. The electric heater will turn on
when the outdoor air temperature is below 10°F. The
VFD will be fully programmed at the factory.
Rotation Sensor
The rotation sensor monitors energy wheel rotation. If
the wheel should stop rotating, the sensor will close a
set of contacts in the unit control center. Field-wiring of
a light (or other alarm) between terminals R and 12 in
the unit control center will notify maintenance personnel
when a failure has occurred.
Dirty Filter Sensor
Dirty filter sensors monitor pressure drop across the
outdoor air filters, exhaust air filters, or both. If the
pressure drop across the filters exceeds the set point,
the sensor will close a set of contacts in the unit control
center. Field-wiring of a light (or other alarm) to these
contacts will notify maintenance personnel when filters
need to be replaced. The switch has not been set at the
factory due to external system losses that will affect the
switch. This switch will need minor field adjustments
after the unit has been installed with all ductwork
complete. The dirty filter switch is mounted in the
exhaust inlet compartment next to the unit control center
or in unit control center.
Optional Component Operation
Microprocessor Control
The microprocessor controller is specifically designed
and programmed to optimize the performance of the
unit with supplemental heating and cooling. This option
ensures that the outdoor air is conditioned to the desired
discharge conditions. The controller and accompanying
sensors are factory-mounted, wired and programmed.
Default settings are pre-programmed, but are easily
field-adjustable.
The microprocessor controller can be interfaced with
a Building Management System through LonWorks®,
BACnet®, or ModBus.
Please refer to the Installation, Operation and
Maintenance manual for detailed information.
Unoccupied Recirculation Damper
The unoccupied recirculation option provides a
recirculation damper from the return air intake to the
supply airstream. If equipped with a room temperature
and/or relative humidity sensor, the unit can cycle on
to maintain unoccupied room set points if there is a call
for unoccupied heating, cooling, or dehumidification.
During the unoccupied mode, the supply and exhaust
(if equipped) fans will be off unless there is a call for
cooling, heating, or dehumidification in the space.
