Hi My name is Brian. Unfortunately Wickes dont actually make this machine it is just branded with their name, so its quite a hard one to answer. E4 error generally refers to the water container being full or the lid not fitted properly, it could also be the switch that senses the water container that is faulty. I apologise for the lack of assistance on this matter, obviously if the above information does not assist you please contact the moderators on site to have your question cancelled. Best regards Brian.