Phase Monitor; Variable Frequency Drive; Supply Fan Vfd Sequence; Optional Component Operation - LG GEN2 Series Installation And Operation Manual

Component Operation

Phase Monitor

The unit control circuitry includes a phase monitor that
constantly checks for phase reversal, phase imbalance,
loss of phase or a power brownout. When it detects a
fault, it cuts off the 24 VAC that goes to the low voltage
terminal strip, thereby shutting off all motors.
Variable Frequency Drive (VFD)
If a VFD was provided and installed at the factory, it has
been pre-set to control the speed of the blower motor for
optimum performance. The motor speed needs to be
verified during test and balance of the unit.
If the system was configured for Constant Air Volume
(CAV), the VFD will operate in an ON/OFF fashion and
the speed of the motor will not change. If the system
was configured for Variable Air Volume (VAV), the
microprocessor will constantly monitor operating
conditions and provide a signal to the VFD, changing
the VFD output as needed.
The VFD may alternatively be connected to an external
signal such as provided by a BMS and be operated by a
2-10 VDC or a 4-20 mA input.

Supply Fan VFD Sequence

Optional Room CO 2 Sensor: The microprocessor will
modulate the supply fan based on a comparison of the
CO 2 set point to the actual CO 2 levels reported from the
sensor. Mechanical high static protection cutoffs
must be installed by others to protect the system and
equipment from over-pressurization.
Optional Duct Static Pressure Sensor: The
microprocessor will modulate the supply fan based on a
comparison of the duct static pressure set point to the
actual duct static pressure level reported from the sensor.
Mechanical high static protection cutoffs must be installed
by others to protect the system and
equipment from over-pressurization. The manufacturer
does not assume responsibility for this.
Optional Building Static Pressure Sensor: The supply
fan is modulated based upon the signal from a building
static pressure sensor. The microprocessor will modulate
the supply fan based on a comparison of the building
static pressure set point to the actual building static
pressure level reported from the sensor.
Optional Single Zone VAV: The microprocessor will use
a space mounted temp sensor to vary heating and
cooling capacity and the airflow delivered by the fan to
maintain room-air temp at a desired set point.
Optional 0-10 VDC by others to VFD: Supply fan is
modulated by a 0-10 VDC, field-provided by others.

Optional Component Operation

Exhaust Fan VFD Sequence

Optional Building Static Pressure Sensor:
exhaust fan is modulated based upon the signal from
a building static pressure sensor. The microprocessor
will modulate the exhaust fan based upon a comparison
of the building static pressure level reported from the
sensor.
Optional Outdoor Air Damper Tracking:
microprocessor will proportionally modulate the exhaust
fan based upon the outdoor air damper position.
Optional Supply Tracking: The microprocessor will
proportionally modulate the exhaust fan based upon the
supply fan.
Optional 0-10 VDC by Others to VFD:
is modulated by a 0-10 VDC provided by others in the
field.
Outdoor Air and Recirculated (Recirc) Air
Damper Sequence
Optional Room CO2 Sensor: The microprocessor
will proportionally modulate the OA/RA dampers based
upon a comparison of the CO2 set point to the actual
CO2 level reported from the sensor. As the CO2 level
rises, the controller will proportionally modulate the
outdoor air damper open, between the minimum and
maximum OA position.
Optional Building Pressure: The OA/RA dampers
will modulate based upon the signal from a building
static pressure sensor. The controller will modulate
the dampers, between the minimum and maximum OA
positions, based upon a comparison of the building
static pressure set point to the actual building static
pressure level reported from the sensor.

Exhaust Fan Only Power

The exhaust fan will have a dedicated power circuit where
in the case of a power outage, the exhaust fan will still run.
A phase monitor will detect an outage or power loss and
open the contact, disconnecting all power to the unit and
controller. An external signal will need to be sent to a relay
to power the exhaust fan, enabling the fan to run at a
maximum speed. This sequence is NOT to be used for high
temperature exhaust applications.
Service Lights
Service lights provide light to each of the compartments in
the energy recovery unit. The lights are wired to a junction
box mounted on the outside of the unit. The switch to turn
the lights on is located in the unit control center. The switch
requires a separate power source to allow for power to the
lights when the unit main disconnect is off for servicing.
The
The
The supply fan