Hydraulic System Troubleshooting – Check the Easy Things First

Insider Secrets To Hydraulics

In Part II of Insider Secrets to Hydraulics, I outline a logical approach to hydraulic system troubleshooting that begins with checking and eliminating the easy things first. The benefits of this approach are clearly illustrated by a troubleshooting situation I was involved in recently.

The machine in question had a complex hydraulic system, the heart of which comprised two engines driving ten pumps. Six of the pumps were variable displacement units and four of these had electronic horsepower control.

The symptoms of the problem were slow cycle times in combination with lug-down of the engines (loss of engine rpm). The machine had just been fitted with a new set of pumps.

The diagnosis of the mechanic in charge was that the hydraulic system was tuned above the power curve of the engines i.e. the hydraulics were demanding more power than the engines could produce, resulting in lug-down of the engines and therefore slow cycle times. The other possible explanation of course, was that the engines were not producing their rated horsepower.

Due to the complexity of the hydraulic system, I knew that it would take around four hours to run a complete system check and tune-up. So in order to eliminate the easy things first, when I arrived on site I inquired about the condition of the engines and their service history. The mechanic in charge not only assured me that the engines were in top shape, he was adamant that this was a “hydraulic” problem.

Four hours later, after running a complete check of the hydraulic system without finding anything significant, I was not surprised that the problem remained unchanged. After a lengthy discussion, I managed to convince the mechanic in charge to change the fuel filters and air cleaner elements on both engines.

This fixed the problem. It turned out that a bad batch of fuel had caused premature clogging of the engine fuel filters, which were preventing the engines from developing their rated horsepower.

If the relatively simple task of changing the engine fuel filters had been carried out when the problem was first noticed, an expensive service call and four hours of downtime could have been avoided.

Keys for Effective Troubleshooting

Expert troubleshooters have a good understanding of the operation of electrical components that are used in circuits they are familiar with, and even ones they are not. They use a system or approach that allows them to logically and systematically analyze a circuit and determine exactly what is wrong. They also understand and effectively use tools such as prints, diagrams and test instruments to identify defective components. Finally, they have had the opportunity to develop and refine their troubleshooting skills.

Corrective Maintenance Task Generation

Corrective Maintenance Task. Generation is best performed by the. same personnel who perform corrective maintenance. The normal. technician’s time schedule does not. allow the time to document tasks in. detail. Some companies rely on the maintenance supervisor to document. and implement new preventative and corrective maintenance tasks.

Availability in a Supply Constrained Environment is the #1 Issue for Refinery Executives

Availability in a Supply Constrained Environment is the Number One Issue for Refinery Executives according to the EPI Center.

Weibull Point Process Applied to Repairable Subsystems

Let's suppose that we have recorded the time when each failure of a repairable subsystem has happened during a season. The arrangement of these failures (black points in Figure 1) along the time axis is called a stochastical realization of failure events.

Energy Savings Through Pump Refurbishment and Coatings

Paul Maier, project manager of the NYSERDA study, states that "Pump sandblasting and coating should be a required step of any pump. refurbishment program." MCWA has also included interior pump coatings as a requirement in its new pump specifications. The goal is that. requiring coatings on the inside of. new pumps will eliminate, or significantly delay, the seemingly inevitable decline in pump performance and efficiency from internal corrosion and tuberculation buildup inside unlined pumps.

Causes of Overheating in Cartridge Mechanical Seals

Too much heat can cause multiple problems with cartridge mechanical seals. Some heat problems are not seal design or seal installation related.

Centrifugal Pump Troubleshooting

You have four opportunities to trouble shoot centrifugal pumps and each opportunity can offer you a clue as to what is wrong with the pump. Let's take a look at each of these conditions:

Hydraulic System Troubleshooting – Check the Easy Things First