Test 62 - Check High Oil Temperature Switch - Generac Power Systems 7 kW NG Repair Manual

Section 4.5
Diagnostic Tests
b. Star t the engine while observing the oil pressure
reading on the gauge.
c. Note the oil pressure.
(1) Normal oil pressure is approximately 35-40 psi with
engine running. If normal oil pressure is indicated, go
to Step 4 of this test.
(2) If oil pressure is below about 4.5 psi, shut engine
down immediately. A problem exists in the engine
lubrication system.
Note: The oil pressure switch is rated at 10 psi for V-twin
engines, and 8 psi for single cylinder engines.
Figure 150. Oil Pressure Switch
5. Remove the oil pressure gauge and reinstall the oil
pressure switch. Do NOT connect Wire 86 or Wire 0 to
the switch terminals.
a. Set a VOM to measure resistance.
b. Connect the VOM test lead across the low oil
pressure (LOP) switch terminals. With the engine
shut down, the VOM should indicate CONTINUITY. If
INFINITY was measured, replace the LOP switch.
c. With the VOM still connected to the LOP switch, set the
AUTO-OFF-MANUAL switch to the MANUAL position.
The VOM should indicate INFINITY once the engine has
had a chance to build pressure.
6. Set the VOM to measure DC voltage.
a. Disconnect Wire 86 at the low oil pressure switch.
b. Connect the black meter test lead to a good ground,
and the red meter test lead to Wire 86. Approximately
3.3 VDC should be measured.
If 3.3 VDC is not measured, go to Test 6 and check
continuity on Wire 86 from the LOP switch back to the J4
connector.
7. Keep the VOM set to measure resistance.
a. Disconnect the J4 Connector from the controller and
disconnect Wire 86 and Wire 0 from the LOP switch.
b. Connect one meter test lead to the disconnected Wire
86 and connect the other meter test lead to J4 Pin 13
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PART 4
(Wire 86). The VOM should indicate CONTINUITY. If
CONTINUITY was not measured repair or replace Wire
86 between the LOP switch and the J5 connector.
c. With Wire 86 still disconnected from the LOP switch and the
J4 connector, connect one meter test lead to disconnected
Wire 86 and the other meter test lead to a clean frame
ground. The VOM should indicate INFINITY. If CONTINUITY
was measured a short to ground exists on Wire 86. Repair
or replace as needed.
Results
1. If the switch operated properly and proper oil pressure
was measured, and Wires 86 and 0 tested good, and/or
the Input would not change on the controller, replace the
controller.
TEST 62 – CHECK HIGH OIL TEMPERATURE
SWITCH
Discussion
If the temperature switch contacts have failed in a closed position,
the engine will fault out on "OVERTEMP". If the unit is in an
overheated condition, the switch contacts will close at 293° F. This
will normally occur from inadequate airflow through the generator.
Procedure
1. Verify that the engine has cooled down (engine block is
cool to the touch). This will allow the contacts in the High
Oil Temperature Switch to open.
2. Check the installation and area surrounding the generator.
There should be at least three feet of clear area around
the entire unit. Make sure that there are no obstructions
preventing cooling air from entering or exiting the enclosure.
3. Disconnect Wire 85 and Wire 0 from the High Oil
Temperature Switch.
4. Set a VOM to measure resistance. Connect the test
leads across the switch terminals. The meter should read
INFINITY (0L).
5. If the switch tested good in Step 4, and a tr ue
overtemperature condition has not occurred, check Wire
85 for a shor t to ground. Remove J1 Connector from
the circuit board. Set the VOM to measure resistance.
Connect one test lead to Wire 85 (disconnected from High
Oil Temperature Switch). Connect the other test lead to a
clean frame ground. INFINITY should be measured.
Testing High Oil Temperature Switch
6. Remove the High Oil Temperature Switch.
7. Immerse the sensing tip of the switch in oil as shown in
Figure 151, along with a suitable thermometer.
8. Set a VOM to measure resistance. Then, connect the VOM
ENGINE/DC CONTROL