Hello. My installer has just put in a W. Bosch 12ri boiler with the horizontal part of the condensate pipe rising up by about 2cms as it goes out of the house rather than down (before it elbows vertically) (looks like they've drilled a hole in the wall at a slight upwards angle by accident). He told me that it didn't matter and that the water pressure would push out the water but I'm not convinced. Surely any water coming out should drain downwards? Could this damage the boiler or make it unsafe? 
