Hi Pete, long time. Looks like the new administration has removed edit facilities. Even with my new hub cap false bottom I slowly build up the flow rate and don't start the recirc for at least 10 min after mash in. I'd have to measure but think flow rate would be about 1.5l/m maximum.
Hi S, I suppose it depends on the surface area of the fb but using a 80ltr tb my flow rate is around 2.75ltr/min, best to leave the mash to settle for 10 mins or so before starting recirc helps too if you've not tried it.