750-96 (revised 2010)
Model CB Packaged Boiler Manual
4-7
4.7 — Firing Preparations for No. 5 Oil: Series 300-500
Suggested oil pressures at high fire operations:
4.6.4 — Starting
When all of the conditions covered above and in Sections 4.1, 4.2, 4.3, and 4.4 are assured, the burner is ready
for firing. Refer to Section 4.10 for further starting and operating information.
4.7 — Firing Preparations for No. 5 Oil: Series 300-500
Prior to initial firing, oil flow, pressure, and temperature should be established and verified. Atomizing air pressure
should also be established as outlined in Section 4.4. The schematic flow diagram in Chapter 1 indicates the flow
of fuel and atomizing air.
If the boiler is a combination fuel model, make certain that the main gas shutoff cock is closed and set the gas/oil
selector switch to “oil.” Insert the burner drawer gun into its most forward position and latch it in place.
4.7.1 — Oil Flow
Open all valves in the oil suction and oil return lines. Momentarily energize the fuel oil pump starter to check for
proper pump rotation. With the rotation verified, prime the suction line strainer with oil and start the fuel oil pump
by closing its power entrance switch. Observe the oil supply pressure gauge for indication that oil flow is estab-
lished. If no pressure shows on the gauge after a few moments, stop the fuel oil pump and re-prime. Heavy oil in
the storage tank must be at a temperature to provide oil viscosity that will permit flow through the oil pump and
suction lines. If oil flow is not established after priming the pump on one or more occasions, conditions preventing
oil flow must be determined and corrected to avoid damage to the pump’s internal mechanism.
A vacuum (or compound pressure-vacuum) gauge should be installed in the oil suction and its reading observed
and recorded for future guidance. This gauge reveals the tightness of the system.
4.7.2 — Oil Pressure
With flow established, check the oil pressure on the gauge at the oil heater. The pressure should be 75 psi.
This adjustment is regulated by the relief valve in the line to the oil heater. Make any initial adjustment necessary to
this valve.
On a cold start, or with cold oil, it may be necessary to open the orifice valve on the fuel oil controller. This valve
must be closed as soon as flow is established.
The pressure reducing valve on the fuel oil controller should be adjusted if necessary to obtain a pressure reading
on the controller oil gauge of approximately 40-50 psi.
After the burner is firing and with properly heated oil, further adjustments can be made, if necessary, to these
valves.
Oil Supply 75 psi
Oil Burner Pressure 42-45 psi
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