Accurex XDG Installation, Operation And Maintenance Manual
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Contents
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Direct Gas Make-Up Air43OPTIONAL RECIRCULATIONTwo Position Recirculation Control• Power passes to inlet damper which opens.• When damper is fully opened, normally opendamper limit switch (DL1) closes.• Power passes to and energizes supply starter relay(RF).• Power passes to normally open fan contact (RF),which is energized and closed. Power reaches andenergizes supply fan. The recirculation damper isclosed.• When the recirculation contact (S3) is closed,the recirculation damper is opened to allowrecirculated air to enter the unit and mix with theheated outside air.Potentiometer Recirculation Control• Power passes to inlet damper which opens.• When damper is fully opened, normally opendamper limit switch (DL1) closes.• Power passes to and energizes supply starter relay(RF).• Power passes to normally open fan contact (RF),which is energized and closed. Power reaches andenergizes supply fan.• The potentiometer will output a 2-10 VDC signalto the recirculation damper actuator to controlrecirculation damper position.External Signal Recirculation• Power passes to inlet damper which opens.• When damper is fully opened, normally opendamper limit switch (DL1) closes.• Power passes to and energizes supply starter relay(RF).• Power passes to normally open fan contact (RF),which is energized and closed. Power reaches andenergizes supply fan.• An external source will provide a 2-10 VDC or4-20 mA signal to the recirculation damperactuator to control recirculation damper position.Sequence of OperationBuilding Pressure Recirculation Control• Power passes to inlet damper which opens.• When damper is fully opened, normally opendamper limit switch (DL1) closes.• Power passes to and energizes supply starter relay(RF).• Power passes to normally open fan contact (RF),which is energized and closed. Power reaches andenergizes supply fan.• The photohelic building pressure controller willmonitor the pressure differential between thepressure in the controlled space and the pressureoutside the controlled space.• If the pressure differential is below the set pointrange established on the photohelic controller,the recirculation damper will be modulated furtherclosed.• If the pressure differential is above the set pointrange established on the photohelic controller,the recirculation damper will be modulated furtheropen.• If the pressure differential is within the set pointrange established on the photohelic controller,the recirculation damper will remain in its currentposition. |
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