Danfoss Charge pressure relief valve adjustment Installation guide

Service Kit Instructions

Series 90 variable pumps Charge pressure relief valve adjustment

CHARGE PRESSURE RELIEF VALVE ADJUSTMENT

Warning The following procedure may require the ve hicle/ machine to be disabled (wheels raised oﬀ the ground, work function disconnected, etc.) in order to prevent injury to the technician and by standers. Take necessary safety precau tions before moving the vehicle/machine.

The following procedure explains how to check and adjust the charge pressure relief valve.

1. Install a 50 bar [1000 psi] pressure gauge in the pump charge pres sure gauge port (M3). Install a 10 bar [100 psi] gauge to measure case pres sure (tee into L1 or L2 or use servo gauge port M4 or M5). Operate the system with the pump in neutral (zero displacement) when measuring pump charge pressure.

2. The table shows the acceptable pump charge pressure range for some charge relief valve settings. These pressures assume 1500 min¯¹ (rpm) and a reservoir temperature of 50°C [120°F], and are referenced to case pressure.

Charge pressure relief valve

Case drain port L1

0 - 10 bar [0 - 100 psi]

K90 Adjusting screw

K10 Lock nut

52 N•m [39 lbf•ft]

Charge pressure gauge port M3

0 - 50 bar [0 - 1000 psi]

9/16-18

23 N•m [17 lbf•ft]

1 1/16-12

115 N•m [85 lbf•ft]

See appropriate table

Listed pressures assume a pump speed of 1500 min-1 (rpm). At higher pump input speeds (with higher charge ﬂows) the charge pressure will rise over the rated set ting.

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P106 162E

Charge pressure ranges

Model code Measured charge pressure*

* This is the actual charge pressure port gauge reading minus the case pressure port gauge reading.

18.1 – 21.7 bar [262 –315 psi]

22.0 – 26.9 bar

[319 – 390 psi]

25.8 – 30.7 bar

[37.4 – 44.5 psi]

CHARGE PRESSURE RELIEF VALVE ADJUSTMENT (continued)

3. Later production Series 90 pumps have an external screw-adjustable charge pressure relief valve. Loosen locknut (K10) and turn the adjusting screw (K90) using a screwdriver or 1/2 in. hex wrench to adjust charge pres sure setting.

Lock nut wrench size

Frame size Wrench size 030 – 100 1-1/16 inch 130 – 250 1-5/8 inch

4. Clockwise rotation of the plug increases the setting and counterclockwise rotation decreases the setting (at a rate of approximately 3.9 bar [50 psi] per turn). Torque lock nut to 52 N•m [39 lbf•ft].

5. Once you achieve the desired charge pressure setting, remove the gauges and plug the ports.

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