TO: All maintenance personnel. FROM: The Fluid Power Safety Institute™. SUBJECT: Inaccuracies in manufacturer's service literature. Introduction - It has been brought to our attention that there are discrepancies between actual operating parameters, and the operating parameters contained in machinery and equipment manufacturer's service literature. This problem typically occurs in cases where a machinery or equipment manufacturer puts a copy of a component manufacturer's literature within the covers of their "master" service manuals. Tell me more! - For example, a manufacturer of a front-end loader specifies a particular brand of pump for their machine. The pump manufacturer has a service manual for the pump that contains all the appropriate specifications and operating parameters. In preparing the "master" service manual for the front-end loader, it is common for manufacturers to simply insert various component manufacturers, already prepared information, in their respective master manuals. And this is where the seeds of discrepancy are sewn! Machinery and equipment manufacturers seldom compare the actual operating parameters of their machines with those given in the respective component manufacturer's service information. This a critical exercise, because, for example, when a pump is installed on a machine, there are a number of factors that could affect its operation, positively or negatively. Here are a few: 1. Length and diameter of inlet line. 2. Length and diameter of case drain line. 3. RPM. 4. Mounting height in relationship to reservoir. Case history - A construction company was experiencing motor shaft-seal leakage problems on a compaction roller it owned. The motor on the unit, is an integral part of a closed-loop system that drives the front and rear roll motors. Upon checking the case pressure, the maintenance mechanic found that it was 80 PSI (5.5 bar). The maintenance mechanic called the roller's engineering group for help, and explained the situation to them. They immediately referred him to the page in the machine's master service manual that contained information about case pressure. Bear in mind, that the page he was referred to was in the document provided by the motor manufacturer! The motor manufacturer specified a case pressure of a maximum of 40 PSI (2.8 bar). It was finally determined that there was an inherent problem in the design of the machine that caused the case pressure to be 80 PSI (5.5 bar). The case pressure was never checked before the machine left the factory. This is just one example, of the many, that plague the industry because many machinery and equipment manufacturers DO NOT check critical operating parameters. This is what happens when machines go from the drawing board to the field! What must I do to correct the problem? - 1. Engineers and Designers - a. Once the machine you design is built and ready for testing, check ALL operating parameters and compare them with the respective component manufacturer's specifications. Here are a few of the operating parameters that MUST be checked: i. Pump inlet restriction. ii. Pump case pressure. iii. Oil temperature. iv. Temperature drop across heat exchanger. v. Pressure drop across heat exchanger. vi. Prime-mover RPM. vii. Pump RPM (if step-up or step-down ratio is used). 2. Instructors - a. Advise your students to look out for this problem. b. Teach them how to perform all of these checks using the proper diagnostic instrumentation. 3. Maintenance Personnel - a. The first time you start a new hydraulic system, regardless of what type of equipment it is on, do the following: i. Get the oil up to normal operating temperature. ii. Subject the machine to the maximum load it will see during any operation, and operate it through several load cycles. iii. Do this when the ambient temperature is extremely low, and repeat when the temperature is extremely high. Record the data in the front of the service manual for future reference. You will not be sorry, because ALL future problems can only be solved if normal operating parameters are known. Remember, it is difficult or impossible to determine abnormal, if normal is unknown! b. If a machine has an "inherent" problem, don’t try to fix it. Give it back to the engineers to fix. c. If you are ever uncertain about a test result, do not hesitate to discuss it with the manufacturer. And don't forget to ask them what the operating parameter was when THEY tested it at the factory - NOT NECESSARILY WHAT IS WRITTEN IN THE SERVICE MANUAL! 4. Safety Personnel - a. Bring this matter to the attention of the appropriate personnel. If necessary, read this safety bulletin in your safety meeting. 5. Students - a. Be prepared to face these kinds of problems in the "real world." b. Discuss these types of issues with your instructor. c. Make sure you learn how to conduct these tests safely and effectively. 6. Technical Writers - a. It is ultimately your responsibility to provide your clients with information that is SAFE and ACCURATE. While it is a simple task to simply insert a component manufacturer's service information between the covers of a master manual, it too, MUST be audited for safety and accuracy. Above all, the operating parameters of your equipment MUST CORRESPOND WITH THE OPERATING PARAMETERS GIVEN IN THE RESPECTIVE COMPONENT MANUFACTURER'S SERVICE MANUALS. Conclusion - There are many machinery and equipment manufacturers who NEVER check and/or verify the critical operating parameters of their respective creations. One should NEVER assume that what is conceived on a drawing board, is consistent with targeted design parameters. In addition, operating parameters MUST be checked under "worst-case" conditions. For example, if a machine is tested in San Diego, and is destined for operation at Alaska's North Slope, it will probably fail. Machinery and equipment manufacturers MUST attempt to test their creations under the same environmental conditions the machines will be exposed to in the field. This safety bulletin offers further testimony to the sad state of the industry with respect to safety and accuracy of written information and instructions. Manufacturers have a moral and ethical responsibility to make certain that the information and recommendations they provide are safe and accurate because people's lives depend on it. Training is the first step in solving these and other issues.

Waiver of Liability -

The Fluid Power Safety Institute™ does everything possible to ensure that the information and drawings contained in this safety notice are accurate, and the suggested procedures are deemed safe and reliable. However, these are general recommendations only and might not be applicable to all situations. You MUST have your engineering department in conjunction with your safety department read these recommendations and make the necessary changes for your application. The Fluid Power Safety Institute™ is not responsible for actions taken by untrained and/or unauthorized persons. Trained, authorized persons only should do ALL fluid power system service, repair, and troubleshooting.