Dickinson Adriatic - Page 28

27
FUEL METERING Cont’d
When the valve is empty of fuel
the float, having no fuel to float
in, drops down.
This lowers the needle inside
the seat, fully opening up the
fuel inlet.
Lowered
open
When fuel is allowed to enter the
valve, it will trickle in around the
lowered needle to fill the reservoir to
its oil level.
Once the reservoir has been filled,
the valve is ready to meter fuel.
When the reservoir is filled up to the
oil level, the float rises and pushes on
the needle until the needle’s rubber
tip seals off the fuel inlet.
Once the valve is filled, more fuel
cannot enter the valve until some of
the reservoir has been depleted.
As the valve drip feeds fuel to the
burner, the oil level will maintain
itself by allowing an equal amount of
fuel to enter.
The valve automatically replaces the
amount of fuel gone into the burner
by replenishing the reservoir
immediately.
Turn Counter
clockwise to ‘ON’
to open fuel flow
A.
< 3 psi
C.
D.
OIL LEVEL
↑ FLOODED VALVE
↑ FLOODED / OVERPRESSURE
↑ EMPTY
↑ FILLING
↑ PRIMED
↑ METERING FUEL
A valve that has accumulated enough
fuel residue to limit the movement of
the float may overfill to the level of the
overflow tube inside.
This is called an overflow. It will result
in increased fuel flow to the burner, as
well as excess fuel escaping via the
overflow line.
If the overflow fitting is blocked (A) or
directed to run uphill to a point higher
than the overflow tube (B) excess fuel in
an overflowing valve will have no
means of escape and will flood the
housing.
A valve in this condition will cause fuel
to fill the valve and leak outside the
metering valve.
OVERFLOW
TUBE
If an overflowing valve with a blocked or
capped overflow fitting (C) is subject to
incoming pressures of greater than 3 PSI
(D) fuel will flood the inside of the valve.
A valve in this condition will leak fuel
from the housing as long as the pump
delivering fuel continues to run.
OIL LEVEL
B.
↑ OVERFLOWING VALVE
VALVE OPERATION:
VALVE MALFUNCTION:
Fuel shut
off closed
Fuel shut
off open
FIG 43
FIG 44
FIG 45
FIG 46
FIG 47
FIG 48
FIG 49