Test 44 - Check 7.5 Amp Fuse; Test 45 - Check Battery - Generac Power Systems 7 kW NG Repair Manual

ENGINE/DC CONTROL
TEST 44 – CHECK 7.5 AMP FUSE
Note: Use the Alarm Log in the control panel to help
troubleshoot various problems. For instance, if the unit
does not crank the control panel will display "Stopped-
Alarm RPM Sensor Loss." If the Fuse is bad and the
unit attempts to crank the alarm log will display "Inspect
Battery" first, and then "Stopped-Alarm RPM Sense Loss."
Discussion
The 7.5 amp fuse is located on the generator control console. A
blown fuse will prevent battery power from reaching the circuit
board with the same result as setting the AUTO-OFF-MANUAL
switch to OFF ; the display and menus will remain active but the
unit will not be able to crank or run.
Procedure
Remove and inspect the 7.5 amp fuse (F1) by pulling the fuse
and visually checking the fuse element (hold the fuse up to
some light and look through it).
Results
1. If the fuse if good, refer back to the Flow Chart.
2. If the fuse is bad, it should be replaced. Use only an
identical 7.5 amp replacement fuse.
3. If fuse continues to blow, proceed to the Problem 19 Flow
Chart.
TEST 45 – CHECK BATTERY
Discussion
Battery power is used to (a) crank the engine and (b) to power
the circuit board. Low or no battery voltage can result in failure
of the engine to crank, either manually or during automatic
operation. The battery charger in the control panel will not
recharge a dead battery.
Procedure
A. Inspect Battery Cables:
1. Visually inspect battery cables and battery posts.
LIQUID
LEVEL
PART 4
1220
1230
Cell # Specific Gravity
1240
1250 1
1260
2
1270
3
4
5
6
Figure 110. Reading a Battery Hydrometer
2. If cable clamps or terminals are corroded, clean away all
corrosion.
3. Install battery cables, making sure all cable clamps are
tight. The red battery cable from the starter contactor (SC)
must be securely attached to the positive (+) battery post;
the black cable from the frame ground stud must be tightly
attached to the negative (-) battery post.
4. Disconnect both negative and positive cables.
Note: Disconnect negative battery cable first.
5. Set a Volt-Ohm-Milliammeter (VOM) to measure DC
voltage.
6. Connect the red meter test lead to the positive battery
post and connect the black meter test lead to the negative
battery post.
7. Set the AUTO-OFF-MANUAL switch to the MANUAL
position; measure and record the voltage.
B. Perform a load test on the Battery:
(Maintenance Free Battery)
1. Using a lead acid battery load tester test the load
capability of the battery.
2. Follow the load tester's manufacturer's instructions carefully.
Figure 109. A Typical Battery Load Tester
1.255
1.260
HIGH READING
1.235
35 POINTS DIFFERENCE
1.250
1.240
LOW READING
1.225
Section 4.5
Diagnostic Tests
32
28
24
20
16
12
8
4
80°
0
26.6°
4
8
12
16
20
24
28
32
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