Is it possible to start the burner outside the boiler ? If this is possible one can quickly get an idea as to what is happening regards the sequence of events. Of course the burner must be positioned so as to be safe in the event it does fire. Before the burner is removed from the boiler certain checks should be carried out regards does the fan run after the lock out button is seen to be 'lit' and depressed. Ist check after the fan runs and then the burner goes to lock out --is the photo cell head clean (accessed at the front of the conrol box when the control box is withdrawn ??
The sequence is then as follows-- fan runs -then ignition high tension spark accross electrodes (provided the gap is set at 3mm at the electrode points and they are in the correct position as per the burner settings in the riello manual) seen inside draught tube (at safe distance) fuel solenoid opens so as atomized fuel discharges. If sequence of events is as stated burner fires. If there is water in the fuel,more usual with corroded steel tanks the burner does not fire although the spark appears to be enveloped by the 'fuel' mist. If this is seen to be the symptom then a gallon or so of fuel must be drained from bottom most connection on tank and water will be seen below any fuel that is in a clear container.Any other water must be cleared from all fuel lines and filters. If there is no spark at the high tension electrodes usually the transformer is the fault because the electrode rods go directly into the transformer in the case of the g5 burner.
The riello site on the web is excellent in respect of a breakdown of their burners but as they point out certain work must be carried out by suitably experienced personel.
Mick Hall, January 2011
