LiftCircuit(MachineSerialNumberabove311000000)
Thechargepumpsupplieschargeuidfortheclosedlooptractioncircuitin
additiontosupplyingowforthesteeringcircuitandtheliftcircuit.Thecharge
pumptakesitssuctionthroughalterfromthetransaxlereservoir(frontaxle).
Thepumpoutputowstothesteeringcontrolvalvebeforereachingthelift
manifoldsothatthesteeringcircuithaspriority.Whentheliftswitchisnotsetto
raiseorlower,uidowenterstheliftmanifoldatthePport.Hydraulicpressure
willtryandraisetheliftarmsuntilthelogiccartridgeLCshiftsopenandprovides
auidpathtothetank(frontaxle).Whenthelogiccartridgeopensiscontrolled
byadjustingthelogiccartridgetothedesiredsettingorcounterbalance.Refer
tothetractionunitOperator’sManualforadditionalcounterbalanceadjustment
information.
RaisetheCuttingDeck(orImplement)
WhentheliftswitchissettotheRaiseposition,solenoidvalveSV1isenergized,
holdinglogiccartridgeLCclosed.Hydraulicowisdirectedthroughsolenoid
valveSV2tothecapend(top)oftheliftcylinders.Whenthecylindersreachthe
endoftheirstroke,oriftheliftarmsarepreventedfromraising,thechargepump
reliefvalveinthehydraulicpumpopensanddirectsthehydraulicowtothetank
(frontaxle)untiltheliftswitchisreleased.
Thehydraulicpressureagainstthecylinderpistonsextendstheliftcylinders.At
thesametime,thepistonspushthehydraulicuidinthelowerportionofthe
liftcylindersoutandtothehydraulicreservoir(frontaxle).Theextendinglift
cylinderscausethecuttingdeck(orimplement)toraise.
Groundsmaster
®
3280-D/3320
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HydraulicSystem:HydraulicFlowDiagrams
05138SLRevB