Generac Power Systems CorePower 6/7 kW 60 Hz Diagnostic Repair Manual page 26

Section 1.7
General Troubleshooting
INTRODUCTION
This section familiarizes the service technician with the
manufacturer recommended procedures for the testing and
evaluation of various problems that can occur on the standby
generators. It is highly recommended that you read these
introductory tips before you attempt to troubleshoot any of the
three main generator components: AC Generator, Engine, or the
Transfer Switch. The Troubleshooting Flow Charts provide the
simplest, quickest, systematic means to troubleshoot the typical
problems that might occur during the lifetime of the unit. If you use
the flow charts and perform the indicated tests, you will be able
to identify the faulty component, which can then be repaired or
replaced as necessary.
The test procedures in each section do require a basic knowledge
of electricity and electrical safety, hand tool skills, and use of Volt-
Ohm-Meters.
RECOMMENDED TOOLS
In addition to the normal hand tools required, some test procedures
may require the use of specialized test equipment. At a minimum
you must have a meter that measures AC voltage and frequency,
and DC voltage and current (digital multi meters (DMM) are
recommended); standard meter test leads, a set of piercing probe
leads , and a set of pin probe leads for the connector pins. The
manufacturer carries a set of acceptable piercing probes (PN
0G7172), or other suppliers piercing probes may be used. Fluke
provides a high quality piercing probe, PN AC89, which is highly
recommended. The manufacturer also carries a set of flexible pin
leads for use with the connector plugs (PN 0J09460SRV).
Figure 14. Test Probes
For engine troubleshooting you will need a good manometer which
measures low pressure in Inches of Water Column (IN WC or IN
H20). An ignition spark tester is also a handy tool to have when
working with air-cooled engines.
Testing and troubleshooting methods covered in each section are
not exhaustive. No attempt has been made to discuss, evaluate
and advise the home standby service trade of all conceivable
ways in which service and trouble diagnosis must be performed.
Accordingly, anyone who uses a test method not recommended
herein must first satisfy himself that the procedure or method he
has selected will jeopardize neither his nor the product's safety,
and will not cause damage to any connectors or components.
Page 24
PART 1
Recommended Tools Check List
p General Mechanics Tool Box
p A Meter Capable of Measuring Frequency (Hz), AC & DC volts,
DC amps, and Ohms
p A Clamp-on Ammeter
p A 1/4" & 3/8" Metric & SAE Socket Set
p Allen Wrenches (Metric & SAE)
p Manometer
p Spark Tester
p Compression Gauge
p Oil Pressure Gauge
p Leak Down Tester
TROUBLESHOOTING REMINDERS AND TIPS
The most important step in troubleshooting is identifying the actual
problem.
The next step is to determine the applicable flow chart to use to
help diagnose the problem. Use the flow chart index for the part
of the generator you are working with. If it is problem with voltage,
use Part 2 – AC Generators; for engine problems use Part 4 –
Engine/DC Control; for a problem with the transfer switch, use
Part 3 – Transfer Switch. The index for each will help you clarify
the problem and the flow chart to use. In each flow chart start at
the top and use the test indicated to verify whether a component
or control item is working properly or not. At the end of each test
follow the "good" or "bad" arrows and perform the next test.
It is always good practice to continue to ask questions during
the troubleshooting process. When evaluating a problem, these
questions may help identify the problem quicker.
• What is it doing? (low voltage; not cranking; not transferring;
etc)
• What should it do? (run and start; transfer; shutdown; etc)
• Does the same thing happen each time?
• When is it happening?
• What could or would cause this?
• What type of test will either prove or disprove the cause of the
fault?
CONNECTORS
A number of the tests require the use of a volt-meter and a set of
wire piercing probes. When using the piercing probes make sure
you use some liquid tape or silicon to coat the insulation where
you pierced it; this will keep moisture out and prevent long term
corrosion.
It is very easy to damage the female pins in the connectors on the
control panel and the C1 connector (Molex connector) which goes
to the alternator can.
DO NOT ATTEMPT TO PUSH PROBE TIPS INTO THE FEMALE
PINS OF THE MOLEX CONNECTORS; doing so will damage the
female pin which will create another problem. Use the piercing
probes on the correct wire to check for the appropriate voltages ;
or use the flexible pin leads, available from the manufacturer (PN
0J09460SRV) to work with the connector plugs.
GENERAL INFORMATION