Sounds a stupid question but I seem to be getting conflicting answers as to whether I can reduce the extractor hoods we're looking at down to 4" or not. One hood manufacturer (LUXAIR) said reducing from 5" to 4" (100mm) would invalidate warranty. NEFF have said SOME of their hoods can be reduced down but only to a minimum of 120mm. I want to continue using the existing 100mm outlet pipe that runs through the ceiling void if at all possible, but don't want to screw up the extractor hood...
100mm / 4" outlet pipe for oven extractor hoods ok?
100mm / 4" outlet pipe for oven extractor hoods ok?