Came across an unusual flue arrangement today,it was fitted in a building I was visiting to change some trv's.It is a mexico he24,the flue comes out of the building into an alleyway with the boiler being situated where the flue would blow down the alleyway length-ways if it was a standard type flue.This flue however terminates as normal with regards to the inlet pipe(outer one),the flue outlet is about 6" longer through the wall,has an elbow on it pointing up,the flue outlet pipe goes up vertically for about 2 metres,another elbow and then a short piece of pipe with a 45 degree cut on the end,all the parts look like Ideal factory stuff,even the brackets holding the inner pipe as it goes up the wall.It has obviously been done to take poc up and out of the alleyway over a flat roof,but I have not seen this done before and cannot find any mention of it in the installation manual as a flue option.I am going to phone Ideal tech help tomorrow to find out if it is legit or wether someone has chopped it about to suit themselves as I suspect.Has anyone else seen similar?