Well, bit the bullet, got a 4 inch, 4 plate bubble cap bubbler. Washed the parts, did a vinegar clean, then a sacrificial run. Had 6L of 60% from a previous SAC run which I watered down to about 20%. I have a keg with a 2200W weldless element and I ran this full bore. All seemed to be going well even with a long heat up time but first of all when the bottom plate started to load up I just could not stop it weeping at the bottom seal. I checked it after the run and I could not see anything wrong with the gasket seating etc.
Next I had it on full reflux and the the bottom and third plate loaded up but the second and top plate did not. Just like the return flow was going straight past. I was doing this on my verandah with the keg wrapped in a sleeping bag but it was cool out there. I had tap water for cooling and it was so cold that the flow was almost completely turned off to get anything going past the RC.
Ended up with less than a litre at 85% abv. Very frustrating. Any thoughts guys?