beautypg.com

Generac Power Systems Recreational Vehicle Generator 5413 User Manual

Page 53

background image

Section 7

DIAGNOSTIC TESTS

TEST 25 – CHECk FUEL SUPPLY

DISCUSSION (GASOLINE MODELS):
If the engine cranks but won’t start, don’t overlook the

obvious. The fuel supply may be low. Many RV gener-

ator installations “share” the fuel tank with the vehicle

engine. When such is the case, the Installer may have

used a generator fuel pickup tube that is shorter than

the vehicle engine’s pickup tube. Thus, the generator

will run out of gas before the vehicle engine.

PROCEDURE:
Check fuel level in the supply tank. Attach a fresh fuel

supply if necessary and restart. Fuel may be stale,

causing a hard start.

RESULTS:
1. If necessary, replenish fuel supply.
2. If fuel is good, go to Test 26 (for Problem 7,

Section 6).

Go to Test 29 for Problem 8 (Section 6).

DISCUSSION (LPG MODELS):
LP gas is stored in pressure tanks as a liquid. The gas

systems used with these generators were designed

only for vapor withdrawal type systems. Vapor with-

drawal systems use the gas vapors that form above

the liquid fuel in the tank. Do NOT attempt to use the

generator with any liquid withdrawal type system.

REGULATOR

PRIMARY
REGULATOR

11 - 14" WATER COLUMN

CARBURETOR

VAPOR
WITHDRAWAL
TANk

Figure 7-27 – Typical Propane Gas Fuel System

Gas pressure delivered to the solenoid valve must be

properly regulated by means of a primary gas regula-

tor. Mount the primary regulator at the gas tank outlet

or in the supply line from the gas tank. The following

rules apply:

• For best results, the primary regulator supplies gas-

eous fuel to the secondary regulator at 11 inches

water column. Do NOT exceed 14 inches water col-

umn.

• The installer must be sure the primary regulator is

rated at sufficient gas flow to operate the generator

plus all other gas appliances in the circuit.

NOTE: Recommended MINIMUM gas flow rate for

all air-cooled RV series generators is 67 cubic feet

per hour.
If an existing primary gas regulator does not have

a sufficient flow capacity for the generator and

other gas appliances in the circuit, (a) install a

primary regulator with adequate flow rate, or (b)

install a separate regulator only and rated at least

67 cubic feet per hour. The inlet side of any pri-

mary regulator that supplies the generator must

connect directly to a gas pressure tank. do NOT

tee the generator line into a gas circuit feeding

other areas.

$

CAUTION! Use only approved components in

the fuel supply system. All components must
be properly installed in accordance with appli-
cable codes. Improper installation or use of
unauthorized components may result in fire
or an explosion. Follow approved methods to
test the system for leaks. No leakage is per-
mitted. Do not allow fuel vapors to enter the
vehicle interior.

LP gas vapors should be supplied to the second-

ary regulator inlet at about 11 inches water column

(positive pressure). The engine pistons draw air in

during the intake stroke (Figure 7-28). This air passes

through a carburetor venturi, which creates a low

pressure that is proportional to the quantity of air

being pumped. The low pressure from the carburetor

venturi acts on the regulator diaphragm to pull the

diaphragm toward the source of low pressure. A lever

attached to the diaphragm opens a valve to permit

gas glow through the carburetor.

GAS IN

TO CARBURETOR

Figure 7-28 – LP Gas Carburetion Diagram

Page 51