And here is a new twist on the issue. Up until yesterday there was never an incidence of this issue when the damper conduit/extension styrofoam was not in place; as long as it remained off, the problem was kind of ok, except the the finished area of the FF section was not finished. Lights and ceiling panels were/are removed.
Then yesterday, the FZ temp showed to be -16F; previously the lowest temp recorded was -13f. This new temp occurred without the damper extension styrofoam in place which is also a first. Thinking about this left me a bit confused until I decided to check the opening (the damper door was open). Reaching in toward the FZ I found the opening to be round and not square and blocked by frost buildup by about 35%. After clearing the frost and within a few hours the FZ temp dropped some 5 degrees.
Have to assume this has something to do with humidity, but there hasn't be much rain recently, so it leaves me kind of stumped.
My review of the interior workings with a bore-scope was a bit revealing, but at the same time confusing. The evaporator was clear of ice on the front side just above the ice maker, but the back side looking through the damper opening was all white, apparently clogged with ice. Couldn't really get a good focus on it because of the angle.
Have to assume that the cause of all this is somehow related to the ice buildup.
Anyone have any thoughts?
TIA, Nick