my boiler decided to stop working the other day.it would not fire up and the fan kept revving on and off.was told i needed a new fan, so bought one and fitted it to no avail.had a second opinion and was told APS so i bought one and fitted it ,to no avail.Funny thing is that when i link out the APS the boiler works perfectly.I ve cleaned the tubes ,venturi,cleaned the old fan and refitted it,cleaned the flue.Stumped every body even the tech team at ideal.Any body got any ideas whats up with my boiler.Its 3 an half years young.Any help appreciated.