On Thu, 20 Sep 2012 01:35:32 +0000 (UTC), gregz
wrote:

Not much to it. You also have option of external flap on vent. What did you
do before, use no venting ?

It was venting but there was no damper at the oven. From what others
said, it is not specific to that unit and it may be at the other end
of the line.