I called up as no hot water. somebody came out (Tuesday 8th) and said they had never seen our type of system before - our house is only 4 years old so wouldnt imagine its that rare! Anyway, he couldnt fix anything there and then and said he would call me next day with prices for parts and a solution. I called Plumbing Force for an update on Thursday 10th and they said they would chase the call back, at the time of writing i still haven't heard from anybody and still have no hot water. pretty rubbish, will not be using them again, and have called a local plumber to come out. All this and i still got charged £94 - daylight robbery springs to mind. Avoid!