2 F C4197 Charge pressure relief valve Gauge portD NOTE: Internal charge pump model shown RH side and bottom view Port B Port D Port C Port A G Gauge port C C4198 High pressure relief valves A and C WARNING Raise the machine securely from the ground before performing system checks to prevent sudden move- ment. PRESSURE TESTS 2.4 The following photos show the various port locations available on the hydrostatic tandem pump for checking system pressure. Completing these pressure test will diagnose any mechan- ical problem in the hydrostatic system. WARNING Use caution when dealing with hydraulic fluid under pressure.
Escaping fluid under pressure can pene- trate the skin and cause serious injury. Installing a gauge into the high pressure gauge ports ‘A’, ‘B’ , ‘C’, or ‘D’ will verify the status of the high pres- sure relief valves. Checking the pressure at port ‘E’ will give accurate charge pressure reading. Checking the pressure at port ‘F’ will verify case drain pressure. Measuring the vacuum at the charge pump inlet can help locate the inlet lines and filters. It would be necessary to tee into the charge pump line fitting. Snubbers are recommended to protect the gauges from pressure spikes. Frequent gauge calibration is necessary to insure accuracy.
Gauge Information A B A System Pressure Gauge 10,000 PSI Gauge (690 Bar) 9/16 - 18 O-Ring Fitting B C D System Pressure Gauge 10,000 PSI Gauge (690 Bar) 9/16 - O-Ring Fitting D E Charge Pressure Gauge Port 500 PSI Gauge (34.5 Bar) 7/8 - 14 O- Ring Fitting F Case Drain Port 500 PSI Gauge (34.5 Bar) 1 - 1/16 - 12 O-Ring Fitting G Charge Pump Inlet Vacuum Vacuum Gauge (30 in. Hg) Tee Into Charge Pump Inlet Tandem pump flow can also measure pump performance. 1 Connect a flow meter between the high pressure ports, one section at a time. 2 Start the engine and increase operating speed between 1775 ~ 1800 RPM. 3 Restrict the flow to show 2000 PSI (137.8 Bar) over charge inlet pressure. Example:
Charge pressure = 220 PSI (15.2 Bar) Gauge pressure reading would need to be 2220 PSI (153 Bar). 4 Minimum flow reading should be 17.1 gal / min. (64.7 L / min). 2-9