Hi Jonathan. The AF 16 is listed at 3HP which probably means you're some distance short on pressure and CFM capability vs a CV Max or an RL 160. My CV pulls a bit over 4 HP with one 160mm drop open. The AF ?probably a 325mm dia impeller or thereabouts.?
Probably best all right not to oversize the drops with that fan.?
The choking effect of the 2x 100mm dia ports on the sander would anyway eliminate most of the benefit of fitting flexibles larger than their open area of 158cm2. Inceasing the vertical drop to 160mm dia above them (202cm2 open area) means it won't cause restriction - whereas your current 125mm dia drop (122cm2) would likely significantly reduce your CFM.?
I don't have much much feel for how large you could make the vertical/how much you could afford slow the airflow before running into transportation difficulties with fine sander dust - perhaps quite a lot unless there's lots of dust.?
Should the proposed 160mm dia new vertical cause any nervousness, you could use 150mm dia instead. ?(also a stock size) That would drop the open area from 202cm2 to 176cm2 - just marginally larger than the open area of the 2 x 100mm dia. Which would avoid choking, but also avoid dropping the airspeed.
The biggie to watch out for with that fan is any sort of choking of the open area below that of the 2 x 100mm (158cm2) ducts anywhere in the run.
ian
