Service Manual

PTOMowCircuit
A3-sectiongearpumpisconnectedtothepiston(traction)pump.Thehydraulic
owforthePTOmowcircuitissuppliedby2sectionsofthegearpump.The
gearpumpsection(P1)nearesttothepistonpumpsupplieshydraulicowin
seriestotherightandleftdecks,whilethenextgearpumpsection(P2)supplies
thecenterdeck.Eachofthe3cuttingdecksiscontrolledbyahydrauliccontrol
manifoldequippedwithasolenoidcontrolvalve(S);logiccartridges(LC1)and
(LC2);abrake-reliefcartridge(RV2);andacircuit-reliefcartridge(RV1).
PTODisengaged
WhenyouturnoffthePTOswitchorifyouraisethedeckwiththePTOswitch
on,thePTOmanifoldsolenoidvalve(S)isnotenergizedandthesolenoidspool
isintheNEUTRALposition.Thesolenoidvalvespoolinneutralallowsasmall
amountofhydraulicowtoreturntothetankthroughamanifoldsensinglinethat
causesapressureincrease,shiftingthelogiccartridgeLC1.Thepumpowis
routedthroughtheshiftedLC1andoutmanifoldportP2.ThelogiccartridgeLC2
staysintheunshiftedpositiontopreventthereturnowfromthedeckmotorto
keepthemotorfromrotating.
Returnowfromthefrontandrightdeckcontrolmanifoldsisroutedthroughthe
oilcooler,oillter,andthentothegear-pumpinput.Returnowfromtheleft
deckcontrolmanifoldsuppliestherightdeck.
PTOEngaged
WhenyouturnonthePTOswitchandlowerthedecks,theTEC-5002controller
doesnotenergizethePTOcontrol-manifoldsolenoidvalve(S).Theshifted
solenoidvalvespoolpreventsthesenselineowthroughthespool,which
causesthelogiccartridgeLC1tobeinitsNEUTRALposition.Thegearpumpow
enteringthemanifoldisroutedouttothemanifoldportM1andthentothecutting
deckmotor.Thereturnowfromthedeckmotoragainentersthemanifoldport
M2.Theshiftedsolenoidvalvespoolallowsasmallamountofhydraulicow
toreturntothetankthroughamanifoldsensingline,whichcausesapressure
increasethatshiftsthelogiccartridgeLC2.Thehydraulicowisroutedthrough
theshiftedLC2,outmanifoldportP2,throughtheoilcoolerandlterandthenis
routedtothegearpumpinput.Thedeckmotorcontinuestorotateaslongas
solenoidvalve(S)isenergized.
Thedeckmotorcasedrainleakagereturnsdirectlytothehydraulicreservoir.
HydraulicSystem:HydraulicFlowDiagrams
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Groundsmaster5900TractionUnit
08159SLRevC