Danfoss 51 Series Service Manual

Procedure
Always follow this procedure when starting-up a new Series 51 or Series 51-1 installation or when
restarting an installation in which either the pump or motor has been removed.
W
Warning
This service procedure may require disabling the vehicle / machine (raising the wheels off the ground,
disconnecting work function, and so forth) while performing, to prevent injury to the technician and
bystanders. Take the necessary safety precautions.
1. Before installing the motor and/or pump, inspect the units for damage incurred during shipping and
handling.
2. Make certain all system components (reservoir, hoses, valves, fittings, heat exchanger, and so forth)
are clean before filling with fluid.
3. Fill the reservoir with recommended hydraulic fluid. Filter using a 10 micron (nominal, no bypass)
filter into the reservoir. Using contaminated fluid may damage components which may result in
unexpected vehicle/machine movement.
4. Fill the inlet line leading from the reservoir to the pump.
5. Check inlet line for properly tightened fittings
6. Make sure the inlet line is free of restrictions and air leaks.
7. Fill the motor and/or pump housing with clean hydraulic fluid before start up. Fill by pouring filtered
oil into the upper case drain port.
C
Caution
Never start the prime mover unless the motor and pump are filled completely with clean hydraulic
fluid.
8. Install a 0-60 bar [0-1000 psi] pressure gauge in the charge pressure gauge port of the pump to
monitor the charge pressure during start-up.
9. Disconnect any external control input signal (linkage for MDC, hydraulic lines for HDC, or electrical
connections for EDC) from the pump control until after initial start-up. This ensures that the pump
remains in its neutral position.
10. Use a common method to disable the prime mover. Jog (slowly rotate) prime mover until charge
pressure starts to rise.
11. Enable prime mover. Start the prime mover and run at the lowest possible speed until charge
pressure is established.
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Warning
Do not start the prime mover unless the pump is in neutral position (swash plate at 0° angle). Take
necessary precautions to prevent machine movement in case pump is actuated in stroke during
initial start-up.
If necessary, bleed excess air from the high pressure lines through the high pressure system gauge
port.
12. Once charge pressure is established, increase speed to normal operating speed.
Charge pressure should be as indicated in the pump model code. If charge pressure is low, shut down
and determine cause. See: Troubleshooting on page 29.
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Caution
Low charge pressure may affect the operators ability to control the machine.
13. Shut down the prime mover.
14. Connect the external control input signal.
Service Manual
Series 51 and 51-1 Motors
Initial startup procedures
©
Danfoss | March 2016 11008567 | AX00000013en-US0202 | 27

Danfoss 51 Series Specifications

General

Brand	Danfoss
Model	51 Series
Category	Engine
Language	English