Hydrostatics Servicing Overview................................................................................................................................................ 5

General Servicing Instructions.....................................................................................................................................................5

Safety Precautions............................................................................................................................................................................6

Symbols used in Danfoss literature............................................................................................................................................7

Design...................................................................................................................................................................................................8

H1 Single Pumps Closed Circuit Pictorial Diagram.............................................................................................................. 9

H1 system schematic.................................................................................................................................................................... 10

Pressure Limiter Valves................................................................................................................................................................ 11

Pressure Limiter Sectional View.......................................................................................................................................... 11

High Pressure Relief Valve (HPRV) and Charge Check Valve.......................................................................................... 12

HPRV/Charge Check Valve Sectional View...................................................................................................................... 12

Charge Pressure Relief Valve (CPRV)....................................................................................................................................... 13

Bypass Function..............................................................................................................................................................................14

System Schematic for Single Pump................................................................................................................................... 14

Electrical Displacement Control (EDC)................................................................................................................................... 15

EDC Operation........................................................................................................................................................................... 16

Manual Override (MOR)............................................................................................................................................................... 17

Manual Displacement Control (MDC) ....................................................................................................................................18

MDC Operation..........................................................................................................................................................................18

MDC Torque................................................................................................................................................................................19

Neutral Start Switch (NSS)..................................................................................................................................................... 19

Case Gauge Port M14.............................................................................................................................................................. 20

Input Speed......................................................................................................................................................................................21

System Pressure..............................................................................................................................................................................21

Servo Pressure.................................................................................................................................................................................22

Charge Pressure..............................................................................................................................................................................22

Charge Pump Inlet Pressure.......................................................................................................................................................22

Case Pressure...................................................................................................................................................................................23

External Shaft Seal Pressure....................................................................................................................................................... 23

Temperature.................................................................................................................................................................................... 23

Viscosity.............................................................................................................................................................................................23

H1 Pumps General Specification.............................................................................................................................................. 24

H1 Pumps Physical Properties ..................................................................................................................................................24

Fluid Specification......................................................................................................................................................................... 25

Filtration System.............................................................................................................................................................................27

Port Locations and Gauge Installation................................................................................................................................... 28

H1P Ports Information.............................................................................................................................................................28

Unintended Machine Movement.............................................................................................................................................29

Start-Up Procedure........................................................................................................................................................................29

High Inlet Vacuum......................................................................................................................................................................... 31

Unintended Machine Movement....................................................................................................................................... 31

Fluid Under Pressure............................................................................................................................................................... 31

Electrical Troubleshooting..........................................................................................................................................................31

Neutral Difficult or Impossible to Find................................................................................................................................... 32

Transmission Operates Normally in One Direction Only.................................................................................................32

System Operating Hot..................................................................................................................................................................32

System Will Not Operate in Either Direction........................................................................................................................ 33

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