CleaverBrooks 4WI, Operation, Service And Parts Manual

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Burner Operation and Control
2-8 750-211 (revised 2009)
Promethean Boilers, Model 4WI Manual
2.6 — Controls Common to Oil-Fired Boilers (Including Combination)
The following items are applicable to all oil fired or gas and oil fired boilers. Additional controls for No. 6 oil are
listed in Section 2.12.
FIGURE 2-8.
Oil Drawer Switch and Controls for Oil Firing
Component/Control Description
1. Oil Drawer Switch Opens the limit circuit if the oil drawer burner gun is not latched in the forward
position required for burning oil.
2. 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.
3. Atomizing Air Pressure
Gauge Indicates the atomizing air pressure at the burner gun.
4. 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.
5. 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 2.7.
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 modu-
lating motor through linkage and the oil metering cam.
B. Oil Modulating Cam: Assembly consisting of a quadrant, a series of adjust-
able allen-head screws, and a contour spring provided 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 adjustment of the pressure of oil at the metering
valve.