8
OIL BURNER
P*LBX furnaces are equipped with
Beckett AF Series oil burners with the
Beckett CleanCut pump and R7184B oil
primary control. The oil burner must align
properly with combustion chamber
(firepot). The combustion chamber is
initially quite soft, but hardens and
becomes quite brittle after the first firing.
The firepot is held in place by a retaining
bracket; however, it is possible for the
firepot to shift if subjected to rough
handling during transit.
BEFORE OPERATING THE
FURNACE CHECK BURNER
ALIGNMENT WITH COMBUSTION
CHAMBER. THE END CONE OF THE
AIR TUBE MUST BE CENTRED TO
THE ACCOMODATING RING
PROVIDED IN THE DESIGN OF THE
COMBUSTION CHAMBER. ADJUST
ALIGNMENT AS NECESSARY
BEFORE THE FIRST FIRING.
OIL BURNER NOZZLES
All furnace models are certified for
multiple firing rates. Choose the firing
rate that most closely matches the
calculated heat loss of the building.
Models, firing rates and nozzles are
listed in Table A-1.
BURNER ELECTRODES
Correct positioning of the electrode tips
with respect to each other, to the fuel oil
nozzle, and to the rest of the burners is
essential for smooth light ups and proper
operation. The electrode tips should be
adjusted to a gap of 5/32”, 1/16” ahead
of the nozzle, 5/16” above the centerline
of the nozzle. The “Z” dimension (front
edge of the burner head to the front face
of the nozzle is 1-1/8 inches.
Electrode positioning should be checked
before the first firing of the furnace.
The electrode porcelains should be free
of cracks, the electrode tips should be
tapered and free of burrs, and the
contact rods must be clean and be in
firm contact with the ignition transformer
contact springs. The electrodes must not
come into contact with the burner head.
OIL BURNER SET-UP
The burner air supply is adjusted to
maintain the fuel to air ratio to obtain
ideal combustion conditions. A lack of air
causes "soft" and "sooty" flames,
resulting in soot build-up throughout the
heat exchanger passages. Excess
combustion air causes a bright roaring
fire and high stack temperatures
resulting in poor fuel efficiency.
PREPARATIONS:
Drill a 1/4” test port in the venting, ideally
at least 2 flue pipe diameters away from
the furnace breeching, if venting
horizontally from the furnace, (typically
P*LBX) or from the flue pipe elbow if
venting vertically before reaching the
furnace. (see Figures 4 and 5).
The test port will allow flue gas samples
to be taken and stack temperatures to be
measured.
Before starting the burner, check the
burner alignment with the combustion
chamber (fire pot), check that the correct
nozzle is tightened into place, and that
the burner electrodes are properly
positioned.
The Beckett burner bulk air band should
be closed, and the air shutter initial
setting should be approximately 7.00.
Note A: Locate hole at least 6 inches on
the furnace side of the draft control.
Note B: Ideally, hole should be at least
12 inches from breeching or elbow.
PROCEDURE:
Start the burner and allow it to run at
least ten minutes. Set the air shutter to
give a good flame visually. The
combustion air supply to the burner is
controlled by adjusting the air shutter on
the left side of the burner, and, if
necessary, the bulk air band. To adjust,
loosen the bolt on the movable shutter.
Move the shutter gradually until a good
flame (visually) has been achieved. Re-
snug the bolt.
Check the initial draft setting as the
furnace warms up. The draft may be
measured at the test port. The final
breech draft should be - 0.02 inches
W.C. to provide adequate over-fire draft.
Check the oil pump pressure. Standard
operating pressure is 100 PSIG.
After reaching steady state, take a
smoke test. If not indicating a trace, set
the combustion air controls to provide a
trace.
Typically, the CO
2
reading will range
from 11.5% to 13.5%.
After the air adjustments have been
completed, and the air shutter or air
Fig. 4: Horizontal Smoke Test Port Location
Fig. 5: Vertical Smoke Test Port Location
