Component Operation - LG AR-DR12-05A 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 CO2 Sensor
The microprocessor will modulate the supply fan based on a comparison of the CO2 set point to the actual CO2 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.
Due to our policy of continuous product innovation, some specifications may change without notification.
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