Figure 4-57.Setting of ignition points and nozzle.
thermometer halfway between the center and outside
of the smoke pipe and not more than 12 inches from the
furnace between the smoke pipe connection and the
draft regulator or barometric damper. Be careful to
prevent the thermometer from being influenced by
cold air taken in by the draft regulator.
The flue-gas analyzer is used to determine the
percentage of CO2 produced by combustion. The CO2
reading shows how much excess air is being used.
Along with the stack temperature, it denotes the
efficiency of the furnace. If, despite a good flame
setting, CO2 readings are low, examine the furnace for
Maintenance requirements include cleaning the
strainer, servicing the valve seat and needle valve, and
adjusting the pressure regulator. Strainers must be
cleaned frequently to prevent the screen from clogging
and causing a shutdown. A good test for valve
operation consists of removing the nozzle line at the
pump connection, starting and stopping the pump, and
observing whether the valve cuts off sharp and lean.
When necessary, the valve is easily serviced by
removing the valve chamber cover, holding spring,
washer, adjusting spring, cap, and bellows assembly.
Then, by taking off the nut that is marked "Nozzle," the
valve, valve guide, and plug assembly can be removed.
Adjustment of the pressure regulator can be done
by replacing the vent plug with a pressure gauge,
removing the cover screw, and using an Allen wrench
to turn the adjusting screw clockwise to increase the
pressure or counterclockwise to decrease the pressure.
Burner failure or improper unit operation can be
caused by various problems. Often the problem can be
pinpointed by observing the type of failure and giving
it some thought before attacking the problem. At other
times, the cause can only be determined by a process of
elimination. Table M in appendix II lists specific oil
pump troubleshooting procedures, while table K, also
in appendix II, lists general oil burner troubleshooting