I am regularly involved in troubleshooting problems with hydraulic equipment. In these
situations, there are two things I always do before reaching for my test gear. The first
is to conduct a visual inspection of the hydraulic system, checking all the obvious things
that could cause the problem in question (never overlook the obvious). The second is to ask
for the schematic diagram for the hydraulic circuit.
What is a hydraulic schematic diagram?
A hydraulic schematic diagram is a line drawing composed of hydraulic symbols that indicate
the types of components the circuit contains and how they are interconnected.
What makes a hydraulic schematic diagram valuable?
A schematic diagram is a 'road map' of the hydraulic system and to a technician skilled in
reading and interpreting hydraulic symbols, is a valuable aid in identifying possible
causes of a problem. This can save a lot of time and money in a troubleshooting situation.
If a schematic diagram is not available, the technician must trace the physical circuit and
identify its components in order to isolate possible causes of the problem. This can be a
time-consuming process, depending on the complexity of the system. Worse still, if the circuit
contains a valve manifold, the manifold may have to be removed and dismantled - just to
establish what it's supposed to do. Reason being, if the function of a component within a system
is not known, it can be difficult to discount it as a possible cause of the problem. The humble
hydraulic symbol eliminates the need to 'reverse engineer' the hydraulic circuit.
Where are all the hydraulic schematic diagrams?
As most hydraulic technicians know, there's usually a better than even chance that a schematic
diagram will not be available for the machine they've been called in to troubleshoot. This is
unlikely to bother the technician because it is the machine owner who pays for its absence.
Where do all the hydraulic schematic diagrams go? They get lost or misplaced, they don't get
transferred to the new owner when a machine is bought secondhand and in some cases they may
not be issued to the machine owner at all. Why? Because generally speaking, hydraulic
equipment owners don't place a lot of value on them.
So if you're responsible for hydraulic equipment and you don't have schematic diagrams for
your existing machines, try to obtain them - before you need them. And ensure that you are
issued with schematic diagrams for any additional hydraulic machines you acquire. It will save
you money in the long run.
"This book has the potential to save many
organizations lots of m0ney. It should be on the bookshelf of every engineer, supervisor, planner and
technician that deals with hydraulic equipment... it's worth its weight in gold." Find out more
Alexander (Sandy) Dunn
Plant Maintenance Resource Center