Hi all, thought i'd post this up for general interest and to add to the growing list of people using PID controllers for their boilers.
I'm still in the process of completing the still itself (2" Boka for now), so I haven't put any load on this unit to see if the SSR heatsink is adequate. I'll be monitoring the heat output closely when I do my vinegar/cleaning runs initially to see how everything goes. There's no airflow when the cover is on, if this becomes an issue I can create a vent and mount a small fan on the right hand side quite easily.
All work inspected by 2 electrical engineers, all given the A-OK and the only recommendation is to earth the DIN rail, which i'll do today. I tried to make this 'modular', the fantastic keg element I got from the 5SD store here will plug into the GPO you can see on the left side. Using the earth pin in the heating element which runs straight from the power input you can see in the pic. Had to tie a knot in the cable as the black plug thing (Wtf is this called) that screws into the box was too big. Used 2 extension cables from Bunnings, cheaper this way as you get both ends and a bunch of cable for $3, instead of one end for $5!!