TM 5-3895-374-24-2
Valve. A proven spark ignited gas pilot’ provides ignition for the
main flame. When the gas pilot has been proven by the flame
detector’, the Diaphragm or Motorized Gas Valve opens and allows
gas at a rate controlled by the Butterfly Valve to go to the burner
head for main flame low fire light off. After a short period of time at
the low fire position, the Modulating Motor will drive the Butterfly
Valve and the Air Dampers to the high fire position. The burner
will stay at high fire until the system pressure or temperature
increases to a selected preset point, at which time a modulating
type controller will drive the Modulating Motor to low fire, or
whatever firing position between low and high fire is required to
match the system load demand. The Modulating Motor will
continually reposition the firing rate in an effort to exactly match
system load demand. Firing Head gas pressures can be taken at
the 1/4” Plugged Test Port (8) located between the Butterfly Valve
and the gas Firing Head. Refer to the Burner Specification
computer
printout supplied with the burner, for specific high fire gas pressure
values. When the system pressure or temperature cutoff point is
reached, the Diaphragm or Motorized Gas Valve closes (normally
the burner will be at the full low fire position at this time) and the
Air Dampers will go to the low fire light off position in preparation
for the next firing cycle. This depiction shows the Linkage in the
low fire light off position.
Refer to page 21 for information on linkage adjustments. Also see
page 20 for information on the VaricamTM modulating characterized
fuel
* Not shown in this diagram. See page 4, Fig. 3.
Note 1
Component operational sequencing will vary with specific
Flame Safeguard Control being used. Refer to the specific
Flame Safeguard Control bulletin supplied with the burner for
complete information.
Figure 21
Typical Oil Burner with On-Oil Fuel/Air Control Mode
MECHANICAL OPERATION: The On-Off system uses a single
stage, high suction lift Oil Pump (2) with a Simplex Oil Nozzle. A
direct spark oil ignition system will normally be supplied, but
certain insurance company codes could require a spark ignited gas
pilot' to provide ignition for the main oil flame. The nozzle oil flow
rate is set by adjusting the Oil Pump Pressure Regulating Valve (3)
(5/32” Allen wrench fitting). Turn clockwise to increase the
pressure and counter-clockwise to decrease the pressure to the
Nozzle. Normal nozzle pressure will be 100 to 300 PSI. Refer to
page 31, Table 9 to determine specific nozzle pressures and firing
rates. Nozzle pressures are taken at the plugged Nozzle Pressure
Gauge Port (6). The oil on-off flow to the Nozzle is controlled by
the Oil Solenoid Valve (1). The Air Dampers (4) are adjusted and
locked
in place with the Air Damper Arms (5). The burner operates at one
fixed firing rate. See page 11, Fig. 11 and pump manufacturer's
bulletin packed with the burner for more information.
* Not shown in this depiction. See page 3. Fig. 1.
Note 1
Component operational
sequencing
will
vary with the specific Flame Safeguard
Control being used. Refer to the specific
Flame Safeguard Control bulletin supplied
with the burner for complete information.
Note 2
The system depicted above is based on the
use of an oil pump manufactured by COMBU
Incorporated. If your system uses other than
a COMBU pump, refer to the oil piping
diagram and oil pump manufacturer’s
bulletin supplied with the burner for
specifics pertaining to your system
(page 3-967)
