BAC 3872C User Manual

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Vibration Cutout Switch (VCOS)
TheMechanicalVibrationCutoutSwitchandtheOptionalElectronicVibrationCutoutSwitch
shouldbetestedandeldadjustedatstart-upandyearlythereafter.
Mechanical Vibration Cutout Switch (Standard)
Set Point Adjustment When Installed:
1. Forsafety,turnoff,thenlockandtag-outtheelectricalsupplytothefanmotor(s).
2. Turnadjustmentscrewcounterclockwise1/8turnatatimeuntilyouhearthecontroltrip.
3. Oncetripped,rotateadjustmentscrew¼turnclockwise.Pushinthemanualresetbutton.
4. Startupthefan(s)todetermineifthestart-upwillcausethecut-outswitchtotrip.
5. IftheVCOSdoesnottrip,startandstopthefantwomoretimes.IftheVCOSstilldoesnot
trip,thencalibrationiscomplete.
6. IftheVCOStrips,repeatsteps1through5untilcalibrationiscomplete.
Electronic Vibration Cutout Switch (Optional)
Twomodelsofelectronicvibrationcutoutswitchesareavailable.Thesinglesetpointmodel
containsonetriplimitforshutdown.Thedualsetpointmodelcontainstwoindependenttrip
limits;oneforalarmandoneforshutdown.Theshutdownset-pointisfactorysetat
0.45in/sec.Additionaldetailscanbefoundinthesubmittalpacket.
Testing:
• Thetestpositionsetsintheminimumsetpointsothatanyvibrationwillcauseatrip
condition.
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Remote Reset:Connectionbetweenterminals5and6latchestriacoutputinalarmstateafter
setpointisexceeded.Openingtheconnectionwillresettheoutputtonon-alarmstate.
Electrical Reset and Start-up Lockout (Optional):
1. Ifratedvoltageiscontinuouslyappliedtotheresetcircuitatunitstart-up,thereset
solenoidenergizesforaxedtimeinterval(approximately30sec),afterwhichtimethe
solenoidisautomaticallyde-energizedbythethermistor.Thisprovidesatriplockout
duringmachinestart-uproughness.
2. Thevoltagemustberemovedfromtheresetcircuitwhenthemachineisstoppedtoallow
thethermistortocooloff.
3. Theswitchmechanismcanberesetelectricallybyamomentaryapplicationofthereset
voltageoritcanberesetmanually.
ATTENTION: The heater control
panel temperature/low level control
can only be used with the supplied
combination temperature/liquid
level sensor probe. Please contact
your local BAC Representative for
replacement parts.
Figure 9. Electronic VCOS with Alarm Contact is Shown
• Thelightwillcomeonimmediately,andthetripwilloccurafterthe
durationofthetimedelay,provingthecompletesystemisoperational.
• Iftestpositionismaintainedforlessthanthedurationofthetimedelay,
thetripwillnotoccur,thuspermittingthesystemtestwithoutshutdown.
Calibration:
• Alightadjacenttothesetpointcontrolcomesontheinstantthemeasured
vibrationlevelexceedsthesetpoint.
• Theunitcanbeperiodicallycalibratedonlinebyturningthesetpoint
controldownuntilthelightcomeson.Thissettingisthencomparedwith
thevibrationmeasuredwithaportablevibrationmeter,thusprovidinga
calibrationcheckoftheunit.
• Ifthetripsettingismaintained,tripwilloccurafterthedurationofthe
timedelay.

BAC 3872C Specifications

General

Brand	BAC
Model	3872C
Category	Air Conditioner
Language	English