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Typical Field Supplied Items - By Others
Shutoff Valve
Suction Supply
Line
Return to Tank
(No Manual
Valves in This
Line)
Typical Field Supplied Items - By Others
Air Filter
Compressor
Oil
Metering
Valve
Low Oil
Pressure
Switch
Gauge
A standard oil pump provides oil at a pressure of about
300 psi to the nozzle. At high fire, the bypass is closed or
nearly closed and all of the pressure is available to the oil
nozzle for maximum flow. As the burner modulates to low
fire, the oil metering valve is opened, causing some oil to
flow through the metering valve and to the return line. As
the metering valve continues to open, more oil is bypassed
and the flow through the nozzle continues to drop. At high
fire, the pressure in the return line is about 150 psi. At low
fire, this pressure drops to about 65 psi. Reducing the
JBE(X) Manual
Optional Low Oil
Pressure Switch
Strainer
Relief Valve
Check
Valve
Figure D-3 Pressure Atomized Oil Schematic
Relief Valve
Size At
Discharge
Air Chamber
Opening In
(200-300 BHP only)
Air Chamber
(Field Piped)
N.C. Main Oil
Safety
Valve
Oil Valve
Ball or
Gate Valve
Optional Pump Set
Factory Assembled
Air Atomizing Light Oil Schematic
Pressure
Gauge Solenoid
Valve
Oil Pump
Modulating
Check
Oil Metering
Valve
Valve
Silencer
Ball Valve to
Adjust Air Volume
Low Atomizing
(Modulating or
Pressure
Fixed Position)
Switch
Check
Valve
Ball
Valve
Back Pressure Reg.
Compound Gauge
Gauge
Oil Pump
Figure D-4
pressure too low can result in poor atomization and a
smoky fire, which limits the turndown to about 3:1. On
standard linkage systems, with combination gas, the
gas turndown will be about the same as the oil turn-
down, based on the air damper positions. Optional
multi-point modulation motors or parallel positioning
systems can be used to improve the turndown of gas
firing on a combination burner. The multi-point modu-
lation motor can provide different low fire positions for
gas and oil, and therefore different turndowns.
Page 31
Solenoid
Valve
Pressure
Gauge
Note: Oil Pump shipped loose
for field piping & mounting
Gauge
Flexible
Oil
Metal
Gauge
Hoses Or
Copper
Tubing
Check Valve
Gate
Check
Valve
Strainer
Valve
Typical Field Supplied Items By Others
Section D - Fuel and Electrical Systems
Oil Nozzle
(Bypassing)
Nozzle
Return
to Tank
Oil
Suction
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