Some electronic oil and gas burners are programmed to go into "latch-up" mode after three unsuccessful attempts at lighting the burner in order to start the boiler. Latch-up mode prevents you from continuing to attempt to light the burner until you reset its electronic controls. It is meant to compel you to contact a service technician who will reset the burner for you after he repairs any underlying burner or boiler problems. However, you can get some models of burner out of latch-up mode yourself.
Locate the control panel of your electronic gas or oil burner and note which indicators are lit to signify that the burner is in latch-up mode. Examples include a single red LED, and both a red and an amber LED.
Press the reset button on your electronic control and hold it until the lit indicator or indicators begin flashing. This usually takes anywhere from 10 to 30 seconds. Hold it for another 20 seconds or so or until the indicators are no longer lit, depending upon the model of your burner.
Press the reset button again to reset and restart your burner. Light your burner as you normally would. You will have three more attempts to do so. Call a technician if you cannot get your burner to ignite after these three attempts and it goes back into latch-up mode.