The part number you're mentioning (EG+G Vactec VTB8440BH) is it from RH manual or some other good source? Because if that's the case, then it would make sense. I will say though that the early Zone VI heads head a different looking cell.
I do know at this point that what Zone VI used was a Hamamatsu branded photocell, but am still waiting on a reply with actual part number. At the end of the day it is the specs not the brand that count. Will post here when available, but if anyone can pitch in on what Ken has upstairs would be just as good.
Last edited by superd; 04-05-2013 at 12:10 PM. Click to view previous post history.