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Premium Commercial Controls
ERV
UNIT OPERATION
5.1.1.3 Optional Drain Overflow Switch
This is an optional accessory, ordered with the unit and factory-installed. The overflow switch
monitors condensate levels in the condensate pan and if unacceptable levels are detected,
it will cause the fans to switch OFF and the dampers will return to their Normally Closed
positions. When the condensate level drops, the unit will return to normal operation.
FIGURE 5.1.3 OVERFLOW SWITCH
5.1.2 Optional Dampers
The ERV unit has optional isolation dampers with end switches. For more information consult
the unit specific IOM.
5.1.3 Fans
The variable speed fans may be driven by VFDs or may be ECM fans. The VFD fans get an
enable signal and both types of fans get a 0–10VDC signal which is proportional to 0–100% fan
command.
Factory VFD settings should not be changed. The settings are available in the
Reference
section
of this manual.
5.1.4 Airflow Measurement
Two pressure transmitters that measure up to 20" w.g. are installed at the fan inlet cones and
are used to measure pressure drop across the fan inlet rings. The scaling screen can be found
in the
I/O Configuration
. The kfactor is factory set for the fans and should only be adjusted
during test and balance. The supply and exhaust flow values can be read in the
Unit
Status
screens.
FIGURE 5.1.4 PRESSURE DIFFERENTIAL TRANSMITTER (TYP)