40 Riello?

Regarding the electrodes, if it fires at all electrodes are usually fine (they don't tend to cause that many probles anyway as long as clean and positioned correctly) but when the burner runs, after 12 seconds listen carefully you should be able to hear them spark (sizzle!) and the fact the techs changed the capacitor and it fired, they sound fine...

I would suspect the pump, if it has tightened it may seem that the capaitor has failed (these can be checked for capacitance using a good multimeter that has a capacitance range on it)

Turn off the oil ,and remove the pump from the motor (3 allen screws between the pump & motor) you will need to disconnect the small copper oil lines fromt he back of the pump also. The run the burner without the pump attached, bet it will run fine! you can also spin the shaft of the pump by hand when its off and it may feel gritty or tighten as you spin it, this would not be a good pump, replace.... your techs should know all this...are they oftec?

T
March 2008