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This section offers instruction on inspection and adjustment of pump components. Read through the
entire topic before beginning a service activity.
on page 26 for location of gauge ports and suggested gauge size.
Standard Procedures
1. Ensure the surrounding area is clean and free of contaminants like dirt and grime.
2. With the prime mover off, thoroughly clean the outside of the pump.
3. Tag each hydraulic line, if removing the pump.
4. When you disconnect hydraulic lines, cap them and plug each open port to prevent contamination.
5. Inspect the system for contamination.
6. Check the hydraulic fluid for signs of contamination: oil discoloration, foam in the oil, sludge, or metal
particles.
7. If there are signs of contamination in the hydraulic fluid, replace all filters and drain the hydraulic
system.
8. Flush the lines and refill the reservoir with the correct filtered hydraulic fluid.
9. Before re-installing the pump, test for leaks.
Manufacturer’s Warranty
Contamination can damage internal components and void the manufacturer’s warranty.
Take precautions to ensure system cleanliness when removing and installing system lines.
Charge Pressure Relief Valve Adjustments
Operate the system with the pump in neutral (zero displacement), when measuring charge pressure.
This procedure explains how to check and adjust the charge pressure relief valve.
Charge Pressure Adjustment
Case drain port L4
Charge pressure gauge port M3
Adjustment
screw
5 mm
Locknut
13 mm
Case drain port L2
12 N•m
[9 lbf•ft]
Optional construction port M14
0 - 10 bar [0 - 100 psi]
9/16 (069/078) / 5/8 in (147/165/210/250/280)
70 N•m [52 lbf•ft] (078)
150 N•m [110 lbf•ft] (147/165/210/250/280)
0 - 10 bar [0 - 100 psi]
3/8 in (069/078) /
9/16 in (089/100/147/165)
5/8 in (210/250/280)
70 N•m [52 lbf•ft]
0 - 10 bar [0 - 100 psi]
3/16 in
0 - 50 bar [0 - 1000 psi]
1/4 in
12 N•m [9 lbf•ft]
24 N•m [18 lbf•ft]
1. Install a 50 bar [1000 psi] pressure gauge in charge pressure gauge port M3.
2. Install a 10 bar [100 psi] gauge at case drain port L2 or L4.
The table below shows the acceptable actual pump charge pressure range for some nominal CPRV
settings (refer to model code located on serial number plate).
Charge Pressure Range according to model code
Code
20
24
26
30
Actual charge
pressure, bar [psi]
20 ± 1.5
[290 ± 21.8]
24 ± 1.5
[348 ± 21.8]
26 ± 1.5
[377 ± 21.8]
30 ± 1.5
[435 ± 21.8]
Service Manual
H1P 069—H1P 280 Axial Piston Single Pumps
Adjustments
34 |
©
Danfoss | January 2021
AX152886482551en-000601