Thanks Charlie, the placing of drawn comb directly above the excluder seems
to be the trick.

Re moisture, here in the Calif foothills, winter temps hang around above
freezing during the day, often freezing at night, and LOTS of rain during
winter, so cold and soggy.  Yet so long as I have strong colonies and tip
the hive forward, moisture is not a problem, so curious about your winter
temps--seems that if you are colder than me, that the humidity would be
lower.

It would be of interest as a project for you Bromenshenk grads, to
duplicate Toomemaa's study (Journal of Apicultural Research 52(2): 81-87
(2013)), in which they placed sheet metal catch sheets to measure the
amount of condensation above the cluster, on the sides of the hive, and
below the cluster.  In their introduction, they state:

Some researchers have successfully overwintered bees in
conditions of limited ventilation. In experiments with colonies which
had closed hive entrances food consumption and bees’ mortality
decreased, and the amount of faeces in the hindgut of bees
decreased 15.0% on average and up to 37.6% maximum as there
was no free flow of cool air into the hive and the bees were calm
(Perepelova, 1947). Similar results were obtained by Michailov (1964).
In his experiments, the wintering of honey bee colonies was most
successful inside a building. In this case, both entrances were closed
and the colonies were covered on top with a cover cloth only. The
upper entrances were opened on 20 February when brood emerged in
the colonies. Colonies with weak ventilation consumed 15.6% less
food and reared 54.1% more brood in spring. Later experiments with
227 colonies in two winters confirmed the results: poorly ventilated
colonies consumed 0.8 kg (7.0 and 6.6%) less food on average, had
fewer dead bees in winter and reared more brood in spring (Michailov,
1964). It shows that weak ventilation reduced heat loss and created
more favourable conditions for the bees, reducing the metabolism
level, food consumption and mortality of bees and helped to preserve
their energy for spring development.

Vert little water condensed on their upper condensers, which makes me
curious about claims that upper ventilation is important for moisture
control.  Clearly it would be of benefit should the entrance become
plugged, although in my climate, the exiting heat from the colony melts a
cavity in the snow covering the entrance.  It would be valuable to run
controlled trials in the field.

-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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