Lpg Fuel Tank Components; Fuel Gauge; Service Valve - Daewoo G420E Service Manual

LPG Fuel Tank Components

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3
1
4
6
5
Figure 5
(1) Fuel Gauge (2) 80% Stop Bleeder
(3) Pressure Relief Valve
(4) Service Valve (Tank end male coupling) (5) Filler Valve
(6) Alignment Pin
(7) Vapor Withdrawal Tube (Only used with Vapor Withdrawal)
(8) 80% Limiter Tube (9) Liquid Withdrawal Tube
(10) Foot Ring (11) Fuel Level Float (12) Collar

Fuel Gauge

In figure 5 a visual fuel gauge is used to show the fuel
level in the tank. A mechanical float mechanism
detects the liquid propane level. A magnet on the end
of the float shaft moves a magnetic pointer in the fuel
gauge. Some units have an electronic sending unit
using a variable resistor, installed in place of a gauge
for remote monitoring of the fuel level. The gauge
may be changed with fuel in the tank. DO NOT
REMOVE THE FOUR LARGE FLANGE BOLTS
THAT RETAIN THE FLOAT ASSEMBLY, WITH
FUEL IN THE TANK!
WARNING
It is not a legal practice to fill the tank
through the liquid contents gauge.
In some applications a fixed tube fuel indicator is
used in place of a float mechanism. A fixed tube
indicator does not use a gauge and only indicates
when the LPG tank is 80% full. The fixed tube
indicator is simply a normally closed valve that is
opened during refueling by the fueling attendant.
When opened during refueling and the tanks LPG
level is below 80%, a small amount of vapor will exit
the valve. When the LPG tank level reaches 80%
liquid propane will begin exiting the valve in the form
of a white mist (Always wear the appropriate
protective apparel when refueling LPG cylinders). In
order for this type of gauge to be accurate, the tank
must be positioned properly. When full (80% LPG)
the valve is closed by turning the knurled knob
clockwise. Typically a warning label surrounds the
fixed tube gauge which reads STOP FILLING WHEN
LIQUID APPEARS.
Tier
G420E/G424E
7 8
12
11
LP Engine

Service Valve

The service valve is a manually operated valve using
a small hand wheel to open and close the fuel supply
to the service line (fuel supply line). The service valve
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installs directly into the tank and has two main
categories, liquid and vapor service valves. Liquid
service valves used on portable LPG tanks use a 3/8"
(3/8" NPT) male pipe thread on the service valve
outlet for attachment of a quick disconnect coupler.
An excess flow valve is built into the inlet side of the
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service valve as a safety device in case of an
accidental opening of the service line or damage to
the service valve itself. The excess flow valve shuts
off the flow of liquid propane if the flow rate of the
liquid propane exceeds the maximum flow rate
specified by the manufacturer.
Figure 6
CAUTION
When the tank is in use the service valve
should be completely open. If the valve is
partly open, the vehicle may not be
getting enough fuel to operate efficiently.
In addition to possibly starving the engine for fuel,
a partly open valve may restrict the flow enough
to prevent the excess flow valve from closing in
the event of a ruptured fuel line.
Most liquid service valves have an internal hydrostatic
relief valve and are usually labeled "LIQUID WITH
INTERNAL RELIEF". The hydrostatic relief valve
protects the fuel service line between the tank and
the lock off from over pressurization. The internal
hydrostatic relief valve has a minimum opening
pressure of 375 PSIG and a maximum pressure of
500 PSIG. These type of relief valves have an
advantage over external relief valves because the
propane is returned to the tank in the event of an over
pressurization instead of venting the propane to
atmosphere.
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Outlet
Excess Flow
Valve
LPG and LPG Fuel Tanks