Planning begins with thinking about the poss ible causes of a problem before going
to the site. This includes the tools and materials necessary to determine what is
causing the problem, and estimating the time required to find and correct it. Friday
afternoon at 4:00 is a bad time to start tearing down a DHW system, particularly if
you may require parts which take 30 days to come in.
Finding the cause is the investigation phase. Start with low impact checks, proceed
in an organized and logical fashion, and at tempt to isolate the results of testing to
the component being tested.
Sometimes the only way to determine if a component is working properly or not is to
replace it and see what happens. Remember that this may fix the symptom but it
can fail to turn up the real cause of a problem.
Repairs can be made on a "band-aid" basis, doing as little as possible to get the
system running again. Another approach is to replace major portions of the system
to be absolutely certain the problem is gone. The correct approach is to determine
what the real cause of a problem is, and make repairs that solve that problem so it
does not happen again.
Whether to repair or replace defective components depends on the cost and
availability of the component. Generally, the more expensive and difficult it is to
obtain something, the more appropriate the repair of the component. If the part is
cheap and readily available, it generally will be replaced. If repairs can be made to
the defective component, it can become the new replacement the next time this
same component fails in this or other systems.
After the cause of a problem has been identified and corrected, inspect and test the
entire system. This confirms that the new components are working, and that no
other problems exist.
The defective components should be tested as well. The best time is usually before
rebuilding. As an example, if a control works fine on a test bench, but not at all at
the site, a problem exists at the site that will not let the new control work there
If the part is truly defective, look for the reason it failed. For example, did the control
get wet? Will the new control also get wet and fail?
The last part of troubleshooting is record-keeping. Maintenance and repair records
are kept to maintain a history of each system. Troubleshooting records should be
part of that written history. In addition, writing down the troubleshooting process
preserves that information for the person who found the problem.
4.1 TROUBLESHOOTING TECHNIQUES