Hello looking to run either 4inch or 3.5 inch straight pipe from my 6466 but the hotside outlet is very small (3 inch outside to outside)
what have any of you done had a bigger flange made up or something?
Cheers

 

It doesn't need bigger. Just use 3" then expand it to 3.5 or 4.

 

3.5 is plenty. Honestly I don’t know if you would see any gain going over 3”.

 

probably not... depends on set up.

just have the downpipe made to go from 3" up to 3.5