U.S. Boiler Company LE DV Series, Installation, Operating And Service Instructions

44

XII.  TROUBLESHOOTING

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 LEDV boiler is the 

result of extensive testing to obtain the best flame 

shape and efficient 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.  FUEL  LEAKS — Any fuel leak between the pump 

and the nozzle will be detrimental to good combus-

tion 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 fire hazard.

3.  SUCTION LINE LEAKS — Any such leaks should 

be repaired, as they may cause erratic burning of the 

fuel and in extreme cases may become a fire hazard.  

Whatever it takes, 

The Oil Must Be Free of Air

.  

This can be a tough problem, but it must be re-

solved.  Try bleeding the pump through a clear tube.  

There must be no froth visible.  There are various 

test kits available to enable you to look at the oil 

through clear tubing adapted to the supply line at the 

pump fitting.  Air eliminators are on the market that 

have potential.  Also, electronic sight glasses are 

being used with good success.  At times, new tubing 

must be run to the tank or new fittings put on.  Just 

make sure you get the air out before you leave.

  Any air leaks in the fuel line will cause an unstable 

flame and may cause delayed ignition noises.  Use 

only flare fittings in the fuel lines.

4.  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 firing rate the greater effect an air leak 

can have on CO

2

 readings.

5.  DIRT — A fuel filter is a good investment. Acciden

-

tal 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 firing 

rate, the smaller the slots become in the nozzle and 

the more prone to plugging it becomes with the 

same amount of dirt.

6.  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 

flame and causes smoke and unburned fuel to pass 

out of the combustion chamber and clog the 

flueways of the boiler.

7.  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 flame 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 locate the tank near the boiler in 

the basement utility room or bury the tank and lines 

deep enough to keep the oil above 40°F.  Check 

environmental issues with local authorities having 

jurisdiction.

8.  FLAME  SHAPE — Looking into the combustion 

chamber through the observation port, the flame 

should appear straight with no sparklers rolling up 

toward the crown of the chamber. If the flame drags 

to the right or left, sends sparklers upward or makes 

wet spots on the target wall, the nozzle should be 

replaced. If the condition persists look for fuel leaks, 

air leaks, water or dirt in the fuel as described above.

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, flame shape, air or water in the fuel lines.

11.  SHUT  DOWN  NOISE — If the flame 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 firing cycles for that 

air to be fully vented through the nozzle. Water in the 

fuel or poor flame shape can also cause shut down  

noises.

NOTICE

CHECK TEST PROCEDURE. A very good test for 

isolating fuel side problems is to disconnect the 

fuel system and with a 24" length of tubing, fire 

out of an auxiliary five gallon pail of clean, fresh, 

warm #2 oil from another source. If the burner runs 

successfully when drawing out of the auxiliary 

pail then the problem is isolated to the fuel or fuel 

lines being used on the jobsite.