Bard H24AA-A Installation Instructions Manual

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Contents

Bard H24AA-A Installation Instructions Manual Manual pdf 14 page image

Manual 2100-647Page 14 of 28WIRING – LOW VOLTAGE WIRINGLow Voltage ConnectionThese units use a 24-volt AC low voltage circuit.Tables 11 – 13 on pages 23 – 25 show the low voltageconnections for units operated with the MV Seriescontroller, MC Series controller or connected directly toa cooling/heating thermostat.All models are equipped with dual primary voltagetransformers. All equipment leaves the factory wiredon 240V tap. For 208V operation, reconnect from240V to 208V tap. The acceptable operating voltagerange for the 240 and 208V taps are:TAP RANGE240 253 – 216208 220 – 187NOTE: The voltage should be measured at the fieldpower connection point in the unit and whilethe unit is operating at full load (maximumamperage operating condition).DIRTY FILTER SWITCH AND RELAYThese units include an adjustable dirty filter indicatorswitch. This switch if connected to normally closedcontacts on the filter relay wired to terminals 10 and11 on the low voltage terminal block.Filter Replacement ProcedureFor units not equipped with economizer:1. Turn off unit power.2. Remove filter door.3. Replace filter.4. Press Reset button.5. Verify filter light is off.6. Replace filter door.7. Turn on unit power.For units equipped with economizer:1. Turn off unit power.2. Remove hood cover.3. Remove mist eliminator. Inspect and clean ifnecessary.4. Remove filter door.5. Remove and replace filter.6. Replace filter door.7. Replace mist eliminator.8. Replace hood cover.9. Turn on unit power.Filter Switch Adjustment1. Turn off unit power.2. Remove upper front door. Front screws on unit topcan be removed for ease of removing upper frontdoor.3. Locate filter switch on control panel side next toblower assembly.4. Remove single phillips head screw on front ofcover. Remove cover.5. Set pressure by adjusting knob. Do not adjustknob drastically to avoid nuisance alarm signalwor non-functionality.6. Replace cover.7. Replace upper front door.8. Turn on unit power.ECONOMIZER FAIL TIME DELAY RELAYNOTE: Applies only to units with economizers.These units employ a time delay relay to open thenomally closed contacts at terminals 12 and 13 on thelow voltage terminal block. This will activate an alarmsignal on the MV Series controller. The time delay is setto 500 seconds as a factory default. Avoid adjustmentto settings lower than 180 seconds.MIS-3054Timer to be set here(500 seconds)MIS-3054