INOV8 Model F240 – Edited September 2008
45
generally term this hose the "final delivery hose" since it supplies oil to the "final delivery
passage" that runs to the nozzle. Flow through this hose is prevented by the oil solenoid
until the burner fires. At that time, the opening of the solenoid allows the oil to flow to the
oil gauge and out to the nozzle. Be aware that any pressure showing on the oil gauge
prior to firing is due to heat expansion of the oil in the final delivery passage and has
nothing to do with true circulating system pressure.
THE PRIMARY (ATOMIZING) AIR SYSTEM
This is the air that is supplied by your air compressor and its function comes into play
when the burner fires. On the module, the air solenoid coil will open when voltage is
applied. Opening the solenoid allows air to flow into the module and go into the Bimba
cylinder (to withdraw the needle) and out the nozzle (to atomize the oil stream). From
there an orange jumper wire conducts the voltage over to the left-most screw of the Dirty
Filter pressure switch to which is also attached the oil solenoid coil wire. This is also the
earliest that the amber Dirty Filter light can come on, since the voltage that drives it
comes from the orange wire circuit. Opening the oil solenoid allows oil to flow to the oil
gauge and nozzle. At the nozzle, it flows through the small hole in the 'spinner' and is
then mixed with the 30-lb. air to form a mist as it squirts out the nozzle. For the oil to get
through the spinner there is one other thing that must also happen: The Bimba cylinder
must draw back.
The Bimba cylinder is a pneumatically operated plunger that is attached to a long needle
that enters the spinner hole between firings. It serves the purpose of purging debris from
the nozzle and preventing oil from dripping out the nozzle and being replaced by air. Air
in the final delivery passage cannot be purged by the vapor eliminator and will cause a
rough start at the next firing. As was mentioned earlier, the opening of the air solenoid
allows air pressure into the Bimba cylinder. This causes it to draw the needle back out of
the spinner hole, allowing oil to flow through. There is a hole in the end of the Bimba
cylinder that extends to the actuator. By placing a wire or small screwdriver in the hole,
you can feel it push back when it draws the needle out of the spinner. At this point, you
have hot atomized oil spraying out the nozzle and through the ignition arc that was turned
on at the same time the orange wire was energized. There should be a flame.
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