On Thu, 29 Dec 2011 17:30:56 -0800 (PST), ChrisCoaster
wrote:

Oil heat + circulator. Should rads be bled when hot or cold?

-ChrisCoaster

Doesn't matter.
If I drained my system then refilled I'd open a second floor rad as I
refilled. When I got water there I'd crack all the others to check.
Every one.
Circ pump is only on when heating.
Same deal, start at the highest, then check the others.
On mine I could feel the that the top of the radiator wasn't hot
and needed bleeding.
But once they are all bled they're good until you drain again.

--Vic