General
Follow this procedure when starting-up a new pump installation or when restarting an installation in
which the pump was removed. Ensure pump is thoroughly tested on a test stand before installing.
W
Warning
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
To protect against unintended movement, secure the machine or disable/disconnect the mechanism
while servicing.
Prior to installing the pump, inspect for shipping damage.
Start-up procedure
1. Ensure the machine hydraulic oil and system components (reservoir, hoses, valves, fittings, and heat
exchanger) are clean and free of any foreign material.
2. Install new system filter element(s) if necessary. Check that inlet line fittings are properly tightened
and there are no air leaks.
3. Install the pump. Install a 50 bar [1000 psi] gauge in the charge pressure gauge port M
4. Fill the housing by adding filtered oil in the upper case drain port. Replace plug.
5. Fill the reservoir with hydraulic fluid of the recommended type and viscosity. Use a 10-micron
reservoir filler filter. Ensure inlet line from reservoir to pump is filled.
6. Disconnect the pump from all control input signals.
After start-up the oil level in the reservoir may drop due to filling of the system components. Check
the level in the reservoir to maintain a full oil level throughout start-up.
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Warning
Damage to hydraulic components may occur if you fail to maintain the oil supply.
7. Use a common method to disable the engine to prevent it from starting. Crank the starter for several
seconds. Do not to exceed the engine manufacturer’s recommendation. Wait 30 seconds and then
crank the engine a second time as stated above. This operation helps remove air from the system
lines. Refill the reservoir to recommended full oil level.
8. Check the pressure gauge at M3. When charge pressure begins to build, enable and start engine. Let
the engine run for a minimum of 30 seconds at low idle to allow the air to work itself out of the
system. Check for leaks at all line connections and listen for cavitation. Check for proper fluid level in
reservoir.
C
Caution
Air entrapment in oil under high pressure may damage hydraulic components. Do not run at
maximum pressure until system is free of air and fluid has been thoroughly filtered.
9. When the pump estabishes adequate charge pressure (as shown in model code), increase engine
speed to normal operating rpm to further purge residual air from the system.
10. Shut off engine. Connect pump control signal. Start engine, checking to be certain pump remains in
neutral. Run engine at normal operating speed and carefully check for forward and reverse control
operation.
11. Continue to cycle between forward and reverse for at least five minutes to bleed all air and flush
system contaminants out of loop.
Normal charge pressure fluctuation may occur during forward and reverse operation.
12. Check that the reservoir is full. Remove charge pressure gauge. Re-intall charge pressure plug. The
pump is now ready for operation.
Service Manual
Series 40 M46 Variable Pumps
Initial startup procedures
©
Danfoss | September 2017
11026743 | AX00000027en-US0202 | 11