How can I repair the Ravenheat 503 efd ignition board. The boiler fires up OK. runs up to heat(maybe 30 mins whatever) then shuts down as normal. To fire up again the fan starts but there is no ignition. Switching off and then pause and back on again is a tempoary fix, so I am using a 24hr preset timer to create the false interruption every hour or so.
A component level cicuit would be great.
Please, can you help ?

David Coxell, November 2010