CHAPTER!
GENERAL
DESCRIPTION
AND
PRINCIPLES
OF
OPERATION
(1) Oil Dra'(ver Switch (Fig. 4-1): Opens the limit
circuit if the oil drawer burner gun
is
not latched
in
the forward position required for burning oil.
(2) Atomizing Air Proving Switch (Fig. 1-1):
Pressure actuated switch whose contacts are
closed when sufficient atomizing air pressure
from the air pump
is
present for oil firing. Oil
valve(s) will not open or will not remain open
unless the switch contacts are closed.
(3) Air Pump Module (Figs. 1-1 and 7-8): This
assembly provides the compressed air required
to atomize the fuel oil for proper combustion.
It
is
started automatically by the programmer's se-
quence.
It
includes the components described
below.
(a)Air
Pump Motor (Fig. 7-8): This
motor drives the air pump and
an
air
cooling fan. The motor
is
started and
stopped simultaneously
with the forced
draft fan motor.
(b)Air
Pump (Fig. 7-8): Provides air for
atomization
of
fuel oil.
(c)Air Filter (Fig. 7-8):
An air inlet
strainer to clean the air supply prior to
entering the air pump.
(d)Check Valve (Figs. 1-11 and 1-12):
Prevents lubricating oil and compressed
air from surging back through the pump
and air filter when the pump stops.
(e)Air·oil Receiver
Tank
(Fig. 7-8):
Holds a supply
of
oil for lubricating the
air pump and separates the
1 ube oil from
the atomizing air before delivery
to
the
oil nozzle.
CHAPTER 1-12
(f)Lube Oil Level Sight Glass (Fig. 7-8):
Indicates the level
of
lubricating oil in the
air-oil receiver tank.
(g)Lube
Oil Cooling Coil (not shown):
Cools the lubricating oil before it enters
the air pump. A fan driven by the air
pump motor circulates the cooling air
over the coil.
(h)Lube
Oil Fill Pipe and Strainer (Fig.
7-8):
Used when adding oil
to
the air-oil
receiver tank.
(4) Atomizing Air Pressure Gauge (Fig. 1-1):
Indicates the atomizing air pressure at the burner
gun.
(5) Low
Oil Pressure Switch (Optional): Switch
contacts open when fuel oil pressure drops below
a selected pressure. The switch will interrupt the
limit circuit upon loss
of
sufficient fuel oil pres-
sure for correct combuStion.
(6) Oil Solenoid Valve (Fig. 1-1): Opens when
energized through contacts
in
the programmer
and allows fuel oil flow from the oil metering
valve to the burner nozzle. A light oil fired burner
uses two valves operating simultaneously.
(7) Fuel Oil Controller (Figs. 1-1 and 1-5): An
assembly
combining
into a single unit the
gauges, regulators and valves required for
regulating the flow
of
fuel oil. All controllers
have the following integral parts.
In
addition to
these, the controller
used
on a No. 6 oil fired
burner has additional components described
in
Section I.
(a
)Oil Metering Valve: The valve meter-
ing stem moves
to
increase or decrease
the orifice area to regulate the supply
of
fuel oil to the burner nozzle
in
accordance
with boiler load variances.
Stem move-
750-150
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