Fuel Supply Lines.15; Excess Flow Valve.15; Leakage Tests.15 - Generac Power Systems NP Series Installation Manual

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 air flow (and vacuum in the venturi throat
should move the regulator valve off its seat and permit
gas to flow.
LEAKAGE TESTS
Do not place the generator into service until you have
properly tested the gas system for leaks. To test the
system, you need a separate source of 12 volts DC to
open the gaseous fuel solenoid valve.
The leak test must comply fully with NFPA, Paragraph
318. AN connections, hoses, valves regulators, fit¬
tings, and other fuel system parts must be tested
under gas or air pressure of not less than 90 psi
(620kPa), while using soap and water or equivalent
solution to check for leaks. Other approved methods
of testing for leaks may be used, if appropriate. DO
NOT USE ANY FLAME TO TEST FOR LEAKS.
FUEL SUPPLY LINES
• Propane gas lines must be accessible, but protected
against possible damage.
• Do NOT connect electrical wiring to any propane gas fuel
line or run wiring alonside the lines.
• Route gas lines away from hot engine exhausts.
• Retain gas lines with metal clamps that do not have
sharp edges.
• Install an approved length of flexible hose between the
gaseous fuel solenoid valve and rigid fuel supply lines.
The flexible line must be non-metallic, non-organic and
non-conductive. It must be approved for use with LP gas.
DANGER; GASEOUS FUEL LINES BETWEEN THE
TANK AND THE SECONDARY REGULATOR ARE
UNDER A POSITIVE PRESSURE (ABOUT 11 INCH¬
ES WATER COLUMN). GAS PRESSURE AT THE
OUTLET SIDE OF THE SECONDARY REGULATOR,
HOWEVER, IS A NEGATIVE PRESSURE AND CAN
DRAW FLAME INSIDE A LINE OR FIHING AND
CAUSE AN EXPLOSION.
EXCESS FLOW VALVE
Propane gas tanks should have an excess flovy valve,
according to NFPA 501C, Paragraph 3-4.4. This valve
and the gas lines must be carefully sized so the valve
will close when a fuel line is severed or broken.
Consult the Natural-LP Gas Association for informa¬
tion and limitations of excess flow valves.
Manual shutoff valves on the supply tank and else¬
where in the system must be fully open when operat¬
ing the generator. The excess flow valve functions
properly only if all valves are fully open.
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