Just looked at the technical manual for this boiler, if the green light is flashing on and off constantly, there is one of two things going on:
Either there is a HW demand (check for dripping hot taps rectify as necessary).
Or there is a back syphon occuring when any cold tap in the house is used/turned off, the resulting back pressure can make the HW flow switch briefly (firing the boiler), try fitting a non-return valve to the cold supply to the boiler.
Carefree
March 2011
howtomendit.com for free repair help, information and advice.
