4 - Sprayer Setup77Open and Closed Centre HydraulicsThis hydraulic block is necessary, if the tractor uses open centrehydraulics and/or load sensing (LS).The valves (pos.1 and 2) is factory set for open centre hydraulics, but ifclosed centre hydraulics is used (also in combination with load sensing),screw in the valves clockwise.± WARNING! Always be sure to fully open or close the selectionvalves for open/closed centre hydraulics.÷ NOTE! The hydraulic block is accessed from below the sprayerchassis.Certain tractor models are able to use Load Sensing without connectingan external sensing line. But if optimal sensing control pressure cannotbe obtained, an external sensing line needs to be connected to thetractor.Connection to TractorIf Load Sensing (LS) is to be used, connect a hydraulic hose from thetractor’s LS port to the O-LS port (D) on this hydraulic block.Connection size for port D is G1/4”.The restrictors inside the hydraulic block have different orificesdepending on the oil flow returned to the tractor’s oil pump.A. Orifice is ø0.8 mm (default setting).B. Orifice is ø1.2 mmC. Orifice is ø1.6 mm• Check the hydraulic flow by activating a hydraulic lever in thetractor. If the reaction time for the hydraulic function is relativelyshort, continue your work with this restrictor installed.• If the reaction time seems too long before the hydraulic function isenabled, switch the plug (E) in port (A) with the plug (F) in port (B)to allow more oil flow to pass through.• If the reaction time is still too long, switch the plug (E) in port (B)with the plug (F) in port (C).• Always mount the plug (E) in the port used, and mount the otherplugs (F) in the ports not used.• Ask your HARDI dealer for correct setup if in doubt.Combinations of settings for hydraulic block:*If the tractor requires pressure relief, contact your tractor dealer for further advice.± WARNING! It is essential that connectors on the sensing line are kept totally clean, so that impurities do not enter thepump. Impurities may cause damage to vital pump parts.Before operating the hydraulics, the valve should be set according to the specific tractor model. If you are unsure ofthe type of hydraulic system in your tractor, please contact your tractor dealer.÷ NOTE! A spare part kit for connecting the hydraulic block to the tractor - ask for HARDI item no. 74193800.Application Valve 1 Valve 2 Port A, B or COpen centre Out Out No changeClosed centre In In No changeLoad sensing (LS) In Out* Change if needed
