CSA RA 350 - Page 36

Form I-RA/D 350/500, Page 36
Compressed air for atomizing the used oil is supplied by a piston-type
compressor mounted on the service tray. Model RA/RAD 350 heaters
require air pressure within a 12 to 15 psi range for proper oil atomiza-
tion. Model RA/RAD 500 heaters require air pressure within a 12 to 16
psi range for proper oil atomization. To assure that the correct atomizing
air pressure is available, a pressure switch permits oil ow to the nozzle
only when a minimum of 12 psi is sensed.
Combustion air is supplied by a blower contained in the burner hous-
ing. An adjustable air shutter and air band located on the outside of the
burner housing control the quantity of combustion air. Both are preset
at the factory and should be changed only if the CO
2
measurement indi-
cates the need to do so. See Check-Test-Start, for factory settings and
instructions for measuring CO
2
.
Ignition of the atomized oil and combustion air mixture is accomplished
by a high voltage spark across the two electrodes located near the atom-
izing nozzle. Ignition of the oil is detected by a cadmium sulde ame
sensor. Light produced by the ame lowers the electrical resistance of
the cad cell. This change is sensed by the ignition controller which al-
lows a continued ow of oil and shuts off the spark transformer after a
30-second trial-for-ignition period.
If for some reason, ignition does not occur or the ame goes out during
the trial period, the primary control will lockout. To restart, the safety switch
must be manually reset by pushing the red reset button on the ignition
control module. Depress and hold the reset button for three seconds. If
the heater does not ignite, contact your service person.
If the instructions in this manual are followed, excessive amounts of
unburned oil will not accumulate inside the combustion chamber If the
caution statement about resetting the controller more than one time is not
heeded, then unburned oil will accumulate in the combustion chamber. If
unburned oil accumulates, DO NOT attempt to re the heater and burn
off the oil. Remove the combustion chamber access panels as described
in Maintenance Section, “Inspecting and Removing Soot and Ash from
the Combustion Chamber/Heat Exchanger”. Wipe out any accumulated
oil with cloth rags. Properly dispose of the rags.
If the ame fails during normal operation, the heater will go into lockout
requiring manual reset of the primary controller. Depress and hold the
reset button for three seconds. If the heater does not ignite, contact your
service person.
If power fails, the heater will shut down and normal trial for ignition will
begin on call for heat when the power is restored.
Approximately 1-1/2 to 2 minutes after the thermostat calls for heat and
ignition is established, the circulating fans or blowers will come on. The
circulating airow will continue about three minutes after the burner shuts
down.
General
Operation
Continued
CAUTION: Do not
reset the primary
control more than
one time. If the
heater does not
ignite, contact your
service person.