LPG
Supply
Pressure: LPG supply pressure must
be maintained
at
9-13 inches (229-330 mm) water
column (WC) under all conditions. Adjust the supply
pressure as follows:
1.
Close the gas shutoff valve(s) at the LPG con-
tainer(s).
2.
Remove the 1/8 inch pipe plug from the regula-
tor test port (Figure 6-30) and connect a ma-
nometer calibrated
in
inches
or
mm WC having
a scale range of at least 14 inches (350 mm).
3.
Open the LPG container shutoff valve and try
starting the genset.
4.
While the genset is running, check the ma-
nometer and adjust the LPG supply pressure
regulator to obtain
11
inches (279 mm) WC. (If
there is a secondary pressure regulator
in
the
supply line, adjust the secondary regulator
instead of the primary regulator at the LPG con-
tainer.)
5.
If the genset will not start, jumper the fuel sole-
noid to the battery cable connections on the
genset so that it stays open (the regulator will
keep gas from flowing)and then check and ad-
just the LPG supply pressure.
6.
If the genset is operable, check LPG supply
pressure under full load. If it drops below the
minimum required pressure, either the LPG
container is too small to provide the rate of va-
porization necessary or it is less than half full or
the supply line is too restrictive.
7.
Disconnect any jumpers which may have been
used to energize the fuel solenoid and thread
in
and tighten the pressure test port plug unless
tests are going to be continued.
Fuel
Shutoff
Solenoid Valve: Replace the fuel so-
lenoid
if
it fails to open (as indicated by the absence
of gas pressure on the manometer scale
in
the pre-
vious test) when it is jumpered across the the bat-
tery cable connections at the genset.
6-33
Demand Regulator
Lock-Off
Pressure Test:
Lock-off pressure is determined as follows by pres-
surizing the back (vent) side of the regulator dia-
phragm to simulate carburetor venturi vacuum:
1.
Continue with the test setup for adjusting LPG
supply pressure shown in Figure 6-30. If the
regulator is being tested on the bench, connect
it
to
a source of air pressure regulated to
11
in-
ches (280 mm)
we.
lA CAUTION!
If
this
is
a bench test
of
the reg-
ulator, make
sure
the diaphragm
is
in
a ver-
tical plane (see Figure 6-29), otherwise the
weight
of
the diaphragm
will
cause erro-
neous readings
of
lock-off
pressure.
2.
''T''
in
two hoses to the end of the hose con-
nected to the regulator vent fitting (3/8 inch
I.
D.). Use one hose to provide the test pres-
sure and the other to measure pressure by con-
necting it to an inclined manometer calibrated
with
0.01
inch or 0.2 mm
we
divisions and hav-
ing a range of at least 1 inch (25 mm) WC.
3.
Disconnect the hose to the carburetor and at-
tach a soap bubble to the regulator outlet hose
fitting. While reading the pressure indicated by
the inclined manometer and watching the soap
bubble, blow lightly into the hose being used to
pressurize the regulator. Regulator lock-off
pressure is the minimum pressure that will
cause gas to flow through the regulator, as indi-
cated by the expanding soap bubble. (At first
the soap bubble may expand due to diaphragm
movement but will stop expanding
if gas
or
air
is not flowing through the regulator.)
For
Gensets
Beginning
Spec F: Repiace the
demand regulator if the lock-off pressure does
not fall between 0.15 and 0.25 inch
we
(3.8
and 6.4 mm WC).
liiwARNINGI
Unauthorized
modifications
or
replacement
of
fuel, exhaust,
air
intake
or
speed
control
system components
that
af-
fect engine
emissions
are
prohibited
by
law
in
the State
of
California.
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