Answer
Aug 17, 2022 - 02:51 AM
Hi there. Thank you for your question.
The rapido diverter will work on a larger diameter downpipe but will not be as efficient at collecting water as the rubber insert will not seal against the inside of the gutter. It will work, but it will take longer to fill the tank. Also, am I correct that the square section pipe you mention is 76mm x 102mm (rather than 7.6 and 10.2mm), it seems a very small size?
Either way, I think I would recommend the standard diverter which takes a little more effort to fit (you need to remove a section of downpipe) but will give you a much more efficient end result. You can see the alternative diverter by clicking this link.
If I can be of any further assistance please feel free to email me at andrew@quickcrop.ie