General
Follow this procedure when starting-up a new pump installation or when restarting an installation in
which the pump has been removed and re-installed on a machine. Ensure pump has been thoroughly
tested on a test stand before installing on a machine.
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 damage that may have occurred during shipping.
Start-up procedure
1. Ensure that 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 M3.
4. Fill the housing by adding filtered oil in the upper case drain port.
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.
7. Re-install plug or fitting removed in step 4.
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 the start-up.
Warning
Damage to hydraulic components may occur if the oil supply is not maintained.
8. Use a common method to disable the engine to prevent the engine 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.
9. When charge pressure begins to appear, 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.
Caution
Air entrapment in oil under high pressure may damage hydraulic components.
Caution
Do not run at maximum pressure until system is free of air and fluid has been thoroughly filtered.
10. When adequate charge pressure is established (as shown in model code), increase engine speed to
normal operating rpm to further purge residual air from the system.
Service Manual
Series 40 M46 Tandem Variable Pumps
Initial startup procedures
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Danfoss | September 2017 11029852 | AX00000030en-US0202 | 11