CHAPTER
I GENERAL DESCRIPTION AND PRINCIPLES
OF
OPERATION
ment
is
controlled by the modulating
motor through linkage and the oil
meter-
ing cam.
(b)Oil Modulating
Cam:
An
assembly
consisting
of
a series
of
adjustable allen-
head screws and a contour spring
provid-
ing for adjustment
of
oil input at any point
in
the modulating range.
( c )Oil Burner Pressure Gauge:
Indicates
pressure
of
the fuel oil at the metering
valve.
(d)Oil Pressure Regulator: For
adjust-
ment
of
the oil pressure at the metering
valve.
(8) Fuel
Oil Pump (Not
~hown):
Transfers fuel
oil from the storage tank and delivers it under
pressure to the burner system.
(9)
Oil Relief Valve (Fig. 1-1): Maintains a con-
stant oil supply pressure to the fuel oil controller
by
bypassing excess fuel oil.
(10) Fuel Oil Strainer (Fig. 1-1): Provided
to
prevent foreign matter from entering the burner
system.
(11) Gas
Pilot: See Section G for description
of
the various components.
(12) Light
Oil Pilot Valve (Not Shown): When
a light oil. pilot
is
furnished, a solenoid valve
is
provided to control the flow
of
fuel to the pilot
nozzle. It
is
energized through programmer con-
tacts.
It
is
de-energized to shut
off
pilot fuel flow
after main flame
is
ignited and established.
(13) Back Pressure Orifice (Fig. 1-1): A
restric-
tion located
in
the oil return line immediately
downstream
of
the fuel oil controller
to
create
back pressure
(100 and 200 series only).
750-150
L ADDITIONAL
CONTROLS
FOR
HEAVY
OIL
NOTE:
Items 6 and 7 are applicable only
on a hot water boiler.
(1)
Oil Heater Switch (Fig. 1-7): Manually
provides power to the oil beater system.
(2)
Oil Heater (Electric) (Figs. 1-2 and 1-8):
Used for heating sufficient fuel oil for low fire
flow during cold starts before steam or hot water
is
available for heating. The heater must
be
turned
off
during extended boiler lay-up, or any
time that the fuel oil transfer pump
is
stopped.
(3)
Oil Heater (Steam/Hot Water) (Figs. 1-2 and
1-8): Heats fuel oil through the medium
of
steam
or
hot water. The electric heater
is
housed
in
the
steam heater, but
is
housed separately on a hot
water heater.
Steam oil heaters on 15 psi boilers
will operate at boiler pressure.
Steam oil heaters
furnished on high pressure boilers are also
to
be
operated at less than 15 psi. This
is
accomplished
through use
of
a steam pressure regulator valve.
(4) Electric
Oil Heater Thennostat (Figs. 1-2 and
1-8): Senses the fuel oil temperature and
ener-
gizes or de-energizes the electric oil heater
to
maintain the required temperature
of
the fuel oil.
(5)
Steam Oil HeaterThennostat (Fig. 1-8): Sen-
ses the fuel oil temperature and controls the
opening and closing
of
the steam heater valve
to
maintain the required temperature
of
the fuel oil.
(6) Hot Water
Oil Heater Thennostat (Fig. 1-2):
This control
is
used on a hot water boiler
to
sense
the fuel oil temperature and control the starting
and stopping
of
the booster water pump to supp I y
hot water to the pre-heating assembly
to
maintain
the required temperature
of
the fuel oil.
(7) Booster Water
Pump (Fig. 1-2): Started and
stopped by the hot water thermostat
to
regulate
the flow
of
hot water through the hot water oil
heater
to
maintain the temperature
of
the fuel oil.
CHAPTER 1·13
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