Fan flue proximity to opening window/vent

[Backboiler]

Assuming the mi's state the normal 300mm distance from the fan flue termination, to an opening window/extractor. Am I correct in thinking if the distance is less than 300mm and the opening is above the flue, I would classify it as AR but if the opening is below or to the side of the flue it would be NCS?

 

[glenno1]

you could contact manufacturer and ask them but id say less than 300mm is at risk because you cant know what it does in all weather conditions you can only know what it is doing while you are there