"BigWallop" wrote in message
om...
If the boiler has an electronic ignition, then check all the electrical
connections inside the boiler control panel. Vibration from running fans,
temperature changes Etc. can cause the connector to loosen off from their
mounts. The cold boiler will spark, but if it's hot it wont, sort of
scenario.





thanks for the replies so far, the boiler has electronic ignition. i have
checked all the connections and they look ok, the only thing i have noticed
is that one of the wires going to the electrodes has a sooty deposit on it
so there may be a short to the case, does the electronic ignition produce
high enough voltages to arc through poor insulation?. looking at the wire
the insulation looks ok