Figure 1.11 Bard Polarity-Voltage Monitor - Bard D25A2PA Installation And Service Instructions Manual

If the VDC wiring is not terminated correctly on the specific polarity-indicated
terminals of the VDC terminal block, the VDC controls and motors will not activate
and the wall-mounted unit will not function.
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If the Polarity-Voltage Monitor is showing a problem with polarity and/or voltage, see pages 41 and 42 of the Service
section of this manual for instructions on checking VDC polarity and verifying incoming VDC voltage.
Manual 2100-643C
Page 18 of 59
FIGURE 1.11
Bard Polarity-Voltage Monitor
The Bard Polarity-Voltage Monitor continually monitors for correct polarity and
voltage. If field wiring is connected improperly, or the voltage is outside of the
system parameters, the Polarity-Voltage Monitor will not allow any VDC voltage to
enter the system, protecting the internal controls and equipment.
When field wiring is correct in voltage and polarity, the
green power (PWR) LED and yellow polarity (POL) LED
will light, and system will operate normally.
If field wiring is incorrect in polarity, the red FAULT
LED will light, and the monitor will not allow VDC
voltage into the system.
If field wiring is correct in polarity but outside of the
required 40VDC – 56VDC, the green PWR LED will not
illuminate and the monitor not allow VDC voltage into
the system.