Lake Monitors Inc.
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Hydraulic System Test Analyzer

System AnalyzerA properly designed and maintained hydraulic system will perform dependably under extreme conditions, but as its components begin to wear overall efficiency of the system will suffer. This loss of efficiency can place a strain on the other components in the system resulting in higher oil temperatures which tend to jeopardize the lubricating properties of oils. The other issue that results from improperly operating hydraulic systems is the increased energy consumption that can be expected.

The Trouble Shooting Problem

Because a loss of efficiency can be attributed to a variety of component failures, a systematic approach to troubleshooting will locate the source of the failure quickly and positively. Simply replacing system components on a trial and error basis will waste time and money.

The Trouble Shooting Solution

To assure proper operating characteristics of hydraulic system components, Lake Monitors offers its proven product and a 5 step method to systematically perform hydraulic troubleshooting.

WARNING: The Analyzer and troubleshooting method are designed to be general in nature and require a knowledgeable user to identify system components and have an understanding of system operating characteristics. Use by non-qualified personnel can lead to serious system damage and/or personal injury.

The heart of the Lake troubleshooting method is the Lake Hydraulic System Test Analyzer. The Analyzer provides direct registration of flow rate, temperature and system pressure. The Analyzer also has an integral load valve that will be adjusted during the troubleshooting process.


STEP 1: Basics

Before any extensive troubleshooting procedures are started, the following two items need to be verified:

  1. Ensure that the suction strainer, located either in the line between the reservoir and pump or inside the reservoir, is clean. Restrictions in the pump's suction line will cause pump cavitation, loss of high pressure and can cause excessive pump noise.
  2. Ensure that the suction line within the reservoir is covered with at least 3" of oil. Failure to maintain a flooded suction line can also lead to the conditions stated above.

STEP 2: Pump Output
To measure the hydraulic horsepower that is being generated by the system's pump, the Lake System Analyzer should be plumbed directly in-line between the system's pump outlet and relief valve. Be sure to orient the Analyzer so that its flow direction arrow corresponds with the actual flow direction.

Open the flow control valve on the Analyzer fully CCW (counter clock wise), start the system and bring the oil temperature to standard operating temperature.

With the pump operating at the RPM recommended by the manufacturer, note the flow rate indicated on the Analyzer. Adjust the load valve on the Analyzer CW until the pressure indicated on the Analyzer is just below the relief valve setting. Note the flow rate on the Analyzer. A drop of more than 10% in flow rate (flow rate under pressure/flow rate at no pressure = less than 0.9) or an indication lower than what is specified by the pump manufacturer indicates a need for pump service.

STEP 3: Relief Valve
To test for proper operation of the system's relief valve, install the Analyzer immediately downstream from the valve ensuring proper orientation of the Analyzer. Open the valve on the analyzer fully CCW, start the system and operate until it reaches normal operating temperature.

With the pump operating at the RPM recommended by the manufacturer, gradually close the Analyzer's load valve noting the pressure that the flow rate drops off at. If that pressure differs from the system's design pressure, the valve may need to be adjusted or replaced.

STEP 4: Testing Hydraulic Cylinder Leakage
If steps one through three are acceptable, the problem lies down stream from those components. One source of poor system performance can be faulty seals in hydraulic cylinders.

To test the cylinder's seals, run the piston to one end of its stroke and leave it stalled in this position under pressure. Crack the fitting on the same end of the cylinder and check for fluid leakage. After checking, tighten the fitting, run the cylinder to the opposite end of the barrel and repeat the test. This test can be repeated at the mid-point of the stroke by blocking cylinder and testing for leakage at that point. Leaking seals should be replaced as needed.

STEP 5: Directional Control Valve
To test for leakage in a directional control valve, disconnect the flow line exiting the control valve and connect the line to the inlet of the Analyzer. Connect the outlet of the Analyzer to a line returning to the reservoir. Fully open the Analyzer's load valve by turning it completely CCW. Start the system's pump and allow the oil to reach proper operating temperature.

To test the valve, shift the valve to allow flow to pass through the Analyzer. Operate the system's pump at its rated RPM – note the flow rate indicated on the Analyzer. Gradually increase the system pressure by turning the Analyzer's load valve CW until system pressure is just below the relief valve setting. Note the indicated flow rate. If the flow rate has dropped more than it did in Step 2, the valve needs servicing.

©2011 Lake Monitors

8809 Industrial Drive, Franksville, WI  53126
Phone: 262-884-9800 | Toll Free: 800-850-6110
Fax: 262-884-9810