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Oil-Burner Maintenance | Up
Utilitiesman Basic Volume 02 - Manual for electric, plumbing, water and other utilities | Next
Fuel Pump |
Figure 4-56.—Rotary-cup oil burner.
Clean the nozzles in the shop on a clean bench. A
nozzle is a delicate device. Handle it with care. Use
kerosene or safety solvent to cut the grease and gum;
use compressed air, if available, to blow the dirt out.
Use goggles for eye protection when blowing dirt out
with compressed air. Never use a Jnetal needle to clean
the opening; it will ruin the nozzle. Sharpen the end of
a match or use a nonmetallic bristle brush to clean the
opening.
When you are checking the nozzle, adjustments
may have to be made in the distance of the nozzle from
the tube end, the distance of the ignition points ahead
of and above the nozzle, and the distance or gap
between the ignition points. Figure 4-57 shows these
nozzles adjustments. The nozzle tip is set 5/8 inch
apart, 1/8 inch ahead of the nozzle, and 1/2 inch above
the nozzle center line. These settings are given only for
this particular illustration. Actual adjustments should
always be made according to the specific settings in the
manufacturer's instruction manual. Always tighten
electrodes securely to ensure permanent adjustment.
When reinstalling either the pump or the motor,
check the coupling to ensure there is no end pressure on
the pump shaft as evidenced by lack of end play. If
there is end pressure, the coupling should be loosened,
moved closer to the pump, and re-tightened.
Troubleshooting
When oil burners are operated, operating problems
will occur. These problems can cause interruption of
service, inefficiency, and damage to the equipment in
the system. To ensure proper operation and efficiency,
you will need to be able to identify and correct these
difficulties. A list of common difficulties and their
remedy are contained in appendix II, table L.
Flame Adjustment
After the burner has been visually adjusted and
allowed to run about 30 minutes, reduce the stack draft
until there is just enough over-fire draft in firebox
to keep the pressure from increasing under unfavorable
draft conditions. The draft regulator helps Jnaintain a
constant draft in the furnace regardless of outside
weather conditions. Adjust the draft by properly
setting the ad-juster. Too little draft is likely to cause
firebox pressure, odors in the building, and possible
smoke or smothering of the flame. Too much draft
accentuates the effect of a possible leak in the furnace,
lowers the percentage of CO2 in the flue gas, and, in
turn, reduces the overall efficiency of the unit. After
the burner flame and draft are properly adjusted, a
flue-gas analysis should show a CO2 content of
approximately 10 percent. If it does not, recheck the
burner air adjustment and inspect for air leaks. For best
results, the flame should be just large enough to heat
the building properly in cold weather.
Air supplied to the burner will then be the
minimum for clean combustion. If the furnace is large
enough and the burner has been set for correct oil flow
and minimum amount of air, stack temperature should
not exceed 600°F. Higher stack temperatures indicate
that the fire is too large or the furnace too small, or that
there is too much excess air.
Test Equipment
It is almost impossible to set and adjust a burner
without instruments or test equipment. Proper
instruments, in good working order, must be available
in the heating shop for use by personnel who service
this equipment.
The draft gauge, usually of the pointer-indicating
type, is used to determine suction in the smoke pipe or
combustion chamber. Suction is measured in inches of
water. Carefully follow the instructions for operating
the instrument.
The stack thermometer is used to indicate the
temperature of gases in the smoke pipe. Insert the
4-36
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