CleaverBrooks CBEX Elite, Operation And Maintenance

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750-368
CBEX Elite 100-1200 HP 2-5
2.4 — Oil System
2.4 — Oil System
The following items are applicable to all oil fired or combination fired boilers.
11. High Gas Pressure Switch A pressure actuated switch that is closed whenever main gas line pressure is
below a preselected pressure. Should the pressure rise above the setting, the
switch contacts will open a circuit causing the main gas valve(s) to close, or pre-
vent the burner from starting. The switch is usually equipped with a device that
must be manually reset after being tripped.
12. Butterfly Gas Valve (not
shown) The pivoted disc in the valve is actuated by connecting linkage from the gas mod-
ulating cam to regulate the rate of gas flow to the burner.
Component Description
Oil Drawer Switch Opens the limit circuit if the oil drawer burner gun is not latched in the forward
position required for burning oil.
Atomizing Air Proving Switch 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 switch contacts are closed.
Atomizing Air Pressure Gauge Indicates the atomizing air pressure at the burner gun.
Oil Solenoid Valves Opens when energized through contacts in the programmer and allows fuel oil to
flow from the oil metering valve to the burner nozzle. A light oil fired burner uses
two valves operating simultaneously.
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 inte-
gral parts.
A. 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 accor-
dance with boiler load variances. Stem movement is controlled by the oil
fuel actuator.
B. Oil Burner Pressure Gauge: Indicates pressure of the fuel oil at the metering
valve.
C. 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 Provides connections for fuel oil supply piping.
Fuel Oil Strainer Prevents foreign matter from entering the burner system.
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).
Low Oil Pressure Switch
(optional) Switch contacts open when the fuel oil pressure drops below selected pressure.
Switch will interrupt the limit circuit upon loss of sufficient fuel oil pressure for
correct combustion.
Component Description