CleaverBrooks CBLE, Operation And Maintenance Manual

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750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual 2-9
2.5 — Controls Common to Oil-Fired Boilers
Fuel Oil Controller 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
2.1 .
•
Oil Metering Valve: Valve metering 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
movement is controlled by the modulating motor through link-
age and the oil metering cam.
•
Oil Modulating Cam: Assembly consisting of a quadrant, a series
of adjustable allen-head screws and a contour spring provided
for adjustment of oil input at any point in the modulating range.
•
Oil Burner Pressure Gauge: Indicates pressure of the fuel oil at
the metering valve.
•
Oil Pressure Regulator: For adjustment of the pressure of oil at
the metering valve.
Oil Relief Valve Maintains a constant oil supply pressure to the fuel oil controller by
bypassing excess fuel oil.
Terminal Block
Fuel Oil Strainer
Prevents foreign matter from entering the burner system.
Gas Pilot See section 2.4 for description of the various components.
Light Oil Pilot Valve: When a light oil pilot is furnished, a solenoid valve is provided to
control flow of fuel to the pilot nozzle. It is energized through pro-
grammer contacts. It is de-energized to shut off pilot fuel flow after
main flame is ignited and established.
Back Pressure Orifice A restriction located in the oil return line immediately downstream
of the fuel oil controller to create back pressure (100 and 200 series
only).
Component Description