<!-- from fixya rte -->Oil leaking from a burner - Heating & Cooling

if its burning it then it would be the piston rings or the valve stem seals, their are the two oil burners. if you cannot see a leak, but there is a place you can get a leak and not see it and that is the main crank oil seal behind the flywheel. this will only leak when the engine is warmed up and under pressure. you will need to remove the inspection plate to have a look inside.

Get a new one sounds like rust

My first guess would be that it sounds like a clogged oil filter, air in your fuel line, is piping overhead, or leak in a fitting or connection causing it to loose it's prime when running.

I have also seen primary controls that are faulty do this, watching the complete cycle of the run time will give you more clues as to when the control actually locks out. Does it lock out during the run cycle as the boiler reaches temp.? If so,check for oil line and suction issues as stated above.

If it locks out on start up after reaching boiler set temperature, if hitting reset right away burner doesn't start and lock out occurs with no motor engaging, check motor (Note: Some motors when HOT will not kick in when powered, but after they cool down naturally they start, motor shaft may also be bound up tight, replacement is necessary) if burner motor spins but does not fire, check for fuel flow to the nozzle, be sure oil is pumping to the nozzle, if it is, clean cad cell eye, and check transformer for spark, if all is good.. replace primary control.

Disclaimer:
Of course all this information is technical troubleshooting information and should be performed by a Licensed Technician, not knowing how to properly test for flame failure can cause injury, fire or worse! Consult a technician in your area if you are not proficient at oil burner repair!

I looked at the drawings from this unit and it is completely sealed between the heat exchanger and supply air. So you should not smell oil at any time you have a leak some place look for that .

Do you see oil or water? If oil then the pump seal is broken and you need oil Tec to change the pump.

Remove the electrodes & nozzle assy

Clean nozzle & check that it is tight

Sand electrodes clean,file ends flat
& set gap

Check the pump for leaks

If the main burners didn't light there shouldn't be a problem. If the main burners came on there could be some damage to the tank but there is no corrective action that can be taken. If damage was done it will usually leak cooking oil when filled. Was the gas valve turned to "pilot" or "on"?

On the oil pump (left hand side of burner) there will ba a small bleeder screw with a 3/8" hex nut attached to it. Get a 2' length of clear hose and make sure itr fits tight in the bleeder. Put the other end in a coffee can or something. Have a helper turn up the thermostat to start the burner motor. At the same time unscrew the bleeder and watch for oil to flow out of the screw. The oil should not have any air bubbles in it. The safety control will time-out between 15 and 45 seconds and shut off the burner. When this happens, tighten the bleeder. You will have to reset the safety control by waiting a minute and depressing the red button. You may need to perform it again to get all the air out. If you are not getting any oil, you may have a plugged oil line, plugged oil filter, a kink in the oil line, a leak at a fitting upstream of the oil pump allowing the pump to **** air or a bad oil pump. There is also a small screen inside the oil pump accessible by removing the 6 Allen head screws on the end of the pump. You will need a pie pan to catch the oil and some thin gasket material to replace the oil seal between the end cap and oil pump. At this point you are on your way to being a top notch oil burner technician!

problem is pump-must replace- there is a valve inside unit that holds pressure to about 150psi -it is leaking by when unit shuts down- causing problem. If left unrepaired you could blow chimeny connection with bad ignition. good luck