My potterton Lynx 2 has the reset light showing. I have reset it many times and it works most times afterwards until the light shows again. Had an engineer out 3 times now who has changed the pump (made no difference) and is now stumped, he has even phoned Potterton direct and they dont know either, but suggested changing 3 parts but if that didnt work then they dont know what to do from then on. Help. This is getting expensive!