When I primed my system I lifted the res' up and 'poured' it down the pump!, the pump needs a
continous stream of water going into it to prime a system. did yours have a continous stream?, or were there bubbles from the system flying into the pump?(I could only do it cause I have a 2litre res!)...
Once it had been primed it would have run OK on parrallel, don't know what difference the temps would have made, but it would have run two rads parrallel if primed...
Glad it's running anyways...
PS. the OCPC Atlantis is my favorite block of the moment
, I'd have one myself if I'd £$% right now!...
OCPC...