Troubleshooting guide

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Q: What are the advantages of each type of LP fuel system?
A: LP Vapor Withdrawal
• Simpler system for the generator set.
• Same low-pressure vapor system as other appliances.
LP Liquid Withdrawal
• Better operation in cold temperatures.
• Complete vaporization pressure regulation system is on
the generator from the factory.
Q: Can LP fuel plug up the regulator?
A: The most common contaminants found in LP fuel are the oils from the LP
pumping facility. The oil is removed from LP fuel at the location the fuel
vaporizes. In liquid withdrawal LP fuel systems, this occurs in the regulator.
Oil contaminants can then clog the regulator. The Marquis Platinum
™
,
Marquis Gold
™
and Emerald Advantage
™
liquid withdrawal LP fuel systems
provide a drain for oil removal. See your Onan Authorized RV Service and
Parts Dealer for assistance.
Q: Can I use the Camp Power 4000, MicroQuiet 4000 or
Emerald 4000 generator to run two air conditioners?
A: No.
Q: Will the starter motor continue to be engaged if the start
button is held too long?
A: All Onan and Camp Power
™
generators are equipped with a start
disconnect feature which will not allow the starter to crank once the
generator is producing electrical output.
Q: Why don’t I have as much power as I think I should?
A: Battery chargers run as “invisible” loads, and can draw as much power as
two air conditioners, depending on size. This can continue for several hours,
depending on battery charger and battery bank size.
Q: Should I get an LP or a diesel generator for my diesel
motorhome? What are the differences?
A: Each fuel option has its own advantages. LP generators generally have a
lower initial cost than diesel units. Plus, they’re smaller and lighter weight,
allowing for more flexibility in the floor plan of large RVs. LP generators also
have less exhaust fume smell. Diesel generators have a much longer engine
life. They consume less fuel, and diesel fuel usually costs less than LP, which
brings additional savings. A diesel generator gives you a common fuel
system, and the convenience of operating your generator from the vehicle’s
main fuel supply. The generator best for you depends on how you use it
and your own personal preferences.
Q: How is LP fuel supplied to my generator?
A: LP fuel is stored in the fuel tank in liquid form with some vapor at the top of
the tank at relatively high pressure. The pressure in the tank is determined by
the ambient (outdoor) temperature. The higher the temperature the higher
the pressure. Ambient heat vaporizes fuel until the pressure won’t allow any
more liquid to vaporize. The tank pressure will be about 200 psi at 110°F,
70 psi at 40°F, and 0 psi at -40°F.
In order for the fuel to be burned at a controlled rate in the generator (or
any other appliance) it must be converted to a vapor form and supplied at
a controlled pressure.
LP fuel systems for many Onan
®
generators are available in two forms,
vapor withdrawal and liquid withdrawal.
Q: What is the difference between LP Vapor and LP Liquid
Fuel Systems?
A: LP Vapor Withdrawal — With a vapor withdrawal system, the LP fuel is
vaporized in the fuel tank by heat input from the environment. The pressure
is reduced to about 11-inches of water column (0.4 psi) at the tank outlet
with a regulator. The vaporized LP fuel flows to the demand regulator on
the generator, which reduces the pressure before it enters the carburetor.
LP Liquid Withdrawal — With a liquid withdrawal system, liquid LP fuel flows
at tank pressure to the generator where heat from the generator converts
the fuel from liquid to vapor form. A two-stage regulator reduces fuel
pressure before it enters the carburetor.