Check Wire 14 Power Supply - Generac Power Systems Guardian 5410 Repair Manual

Section 7
DIAGNOSTIC TESTS
The greater the airflow through the carburetor venturi,
the lower the pressure at the venturi throat. The lower
the pressure at the venturi throat, the greater the dia-
phragm movement, and the greater the movement
of the regulator valve. The more the regulator valve
opens, the greater the gas flow that is proportional to
airflow through the generator.
The following facts about the secondary regulator
must be emphasized:
• The regulator must be sensitive to venturi throat
pressure changes throughout the operating range.
• The regulator must be properly adjusted so it will
stop the flow of gas when the engine is not running
(no air flow through the carburetor).
• The slightest airflow (and vacuum in the venturi
throat) should move the regulator valve off its seat
and permit gas to flow.
PROCEDURE:
A water manometer or a gauge that is calibrated in
"ounces per square inch" may be used to measure
the fuel pressure. Fuel pressure at the inlet side of the
LPG Shut Off Valve should be between 11-14 inches
water column as measured with a manometer. The LP
system must be able to maintain 11-14 inches water
column under all load requirements.
1. Turn LP supply to generator off.
2. Remove the Gas Pressure Tap from the fuel regu-
lator and install manometer to this port.
3. Turn LP supply to generator on, the gauge should
read 11-14 inches water column.
4. For Problem 8 only (Section 6), start the engine
and the gauge should read 11-14 inches water
column.
GAS
PRESSURE
TAP
Figure 7-29. – Fuel Regulator
RESULTS:
1. If the LP gas pressure is less than 11-14 inches
water column the fuel supply system must be
corrected in order to maintain 11-14 inches water
column.
Page 52
FUEL HOSE
BRASS
HOSE
FITTING
2. If the LP gas pressure is between 11-14 inches
water Column, proceed to Test 26 for Problem
7 (Section 6). Proceed to Test 29 for Problem 8
(Section 6).
TEST 26 – CHECk WIRE 14 POWER SUPPLY
DISCUSSION:
When the engine is cranked, Printed Circuit Board
action must deliver battery voltage to the Wire 14 cir-
cuit, or the engine will not start. This is because the
Wire 14 circuit will operate the Fuel Pump and Fuel
Solenoid on Gasoline models. On LP models it oper-
ates the LPG Shut-off valve.
PROCEDURE:
Inside the generator panel, locate the 4-tab Connector
(Figure 7-30). Then, proceed as follows:
Figure 7-30. – The 4-tab Connector
1. Set a VOM to read battery voltage (12 VDC).
2. Connect the meter positive (+) test lead to the 4-
tab Connector, the common (-) test lead to frame
ground.
3. Crank the engine and the meter should read bat-
tery voltage. If battery voltage is not measured,
proceed to Step 4.
4. Check Wire 14 for poor connection from the 4-tab
Connector to the Printed Circuit Board.
5. Crank the engine. The meter should indicate bat-
tery voltage.
RESULTS:
1. If the meter indicated battery voltage, go to Test
20 "Check Start-Stop Switch".
2. If battery voltage was NOT indicated in Step 3 but
is indicated in Step 5, check Wire 14 between the
4-tab Connector and the Printed Circuit Board.
a. Repair, reconnect or replace Wire 14 as neces-
sary.
3. If battery voltage was not indicated in Step 5,
replace the Printed Circuit Board.