47
A.
COMBUSTION
1. NOZZLES — Although the nozzle is a relatively
inexpensive device, its function is critical to the
successful operation of the oil burner. The selection
of the nozzle supplied with the MPO boiler is the
result of extensive testing to obtain the best fl ame
shape and effi cient combustion. Other brands of the
same spray angle and spray pattern may be used but
may not perform at the expected level of CO
2
and
smoke. Nozzles are delicate and should be protected
from dirt and abuse. Nozzles are mass-produced
and can vary from sample to sample. For all of
those reasons a spare nozzle is a desirable item for a
serviceman to have.
2. FLAME SHAPE — Looking into the combustion
chamber through the observation port, the fl ame
should appear straight with no sparklers rolling up
toward the crown of the chamber. If the fl ame drags
to the right or left, sends sparklers upward or makes
wet spots on the chamber walls, the nozzle should
be replaced. If the condition persists look for fuel
leaks, air leaks, water or dirt in the fuel as described
above.
3. FUEL LEAKS — Any fuel leak between the
pump and the nozzle will be detrimental to good
combustion results. Look for wet surfaces in the air
tube, under the ignitor, and around the air inlet. Any
such leaks should be repaired as they may cause
erratic burning of the fuel and in the extreme case
may become a fi re hazard.
4. AIR LEAKS — Any such leaks should be repaired,
as they may cause erratic burning of the fuel and in
extreme cases may become a fi re hazard.
5. GASKET LEAKS — If 11.5 to 12.5% CO
2
with a
#1 smoke cannot be obtained in the breeching, look
for air leaks around the burner mounting gasket,
observation door, and canopy gasket. Such air leaks
will cause a lower CO
2
reading in the breeching. The
smaller the fi ring rate the greater effect an air leak
can have on CO
2
readings.
6. DIRT — A fuel fi lter is a good investment.
Accidental accumulation of dirt in the fuel system
can clog the nozzle or nozzle strainer and produce a
poor spray pattern from the nozzle. The smaller the
fi ring rate, the smaller the slots become in the nozzle
and the more prone to plugging it becomes with the
same amount of dirt.
7. WATER — Water in the fuel in large amounts will
stall the fuel pump. Water in the fuel in smaller
amounts will cause excessive wear on the pump,
but more importantly water doesn’t burn. It chills
the fl ame and causes smoke and unburned fuel to
pass out of the combustion chamber and clog the
fl ueways of the boiler.
SECTION XI: TROUBLE SHOOTING
8. COLD OIL — If the oil temperature approaching
the fuel pump is 40°F or lower, poor combustion or
delayed ignition may result. Cold oil is harder to
atomize at the nozzle. Thus, the spray droplets get
larger and the fl ame shape gets longer. An outside
fuel tank that is above grade or has fuel lines in a
shallow bury is a good candidate for cold oil. The
best solution is to bury the tank and lines deep
enough to keep the oil above 40°F.
9. HIGH ALTITUDE INSTALLATIONS — Air
openings must be increased at higher altitudes. Use
instruments and set for 11.5 to 12.5% CO
2
.
10. START-UP NOISE — Late ignition is the cause
of start-up noises. If it occurs recheck for electrode
settings, fl ame shape, air or water in the fuel lines.
11. SHUT DOWN NOISE — If the fl ame runs out of
air before it runs out of fuel, an after burn with noise
may occur. That may be the result of a faulty cut-off
valve in the fuel pump, or it may be air trapped in the
nozzle line. It may take several fi ring cycles for that
air to be fully vented through the nozzle. Water in the
fuel or poor fl ame shape can also cause shut down
noises.
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B.
OIL PRIMARY CONTROL
1. Burner (control) will not come on.
a. No power to control.
b. Control is in lockout or restricted mode. Press
reset button for one (1) second to exit lockout. If
control has recycled three times within the same
call for heat, it will enter into restricted mode.
To reset from restricted mode, refer to Section
VIII, Paragraph I, No. 2 for details.
c. CAD cell seeing light.
d. CAD assembly defective.
e. Control motor relay is stuck closed (see note
below).
2. Burner (control) will light, then shut down after a
short time, then restart after one (1) minute.
a. CAD cell is defective.
Summary of Contents for MPO Series
Page 6: ...6 Figure 1 MPO 84 Thru MPO 231 Water Boiler ...
Page 22: ...22 Figure 13A Water Boiler Piping for Circulator Zoned Heating System Supply Side Circulator ...
Page 38: ...38 Figure 27 L1 L2 and V1 Head Electrode Positioning and Gun Setting Beckett AFG ...
Page 49: ...49 SERVICE RECORD DATE SERVICE PERFORMED ...
Page 50: ...50 Bare Boiler Assembly ...
Page 52: ...52 Bare Boiler Assembly ...
Page 54: ...54 Jacket Assembly ...
Page 56: ...56 MPO84 Thru MPO231 Water Boilers Trim and Controls ...
Page 58: ...58 Beckett AFG Burner ...
Page 61: ...61 Figure A2 LWCO Location ...
