Hi,
During a recent kitchen remodeling project, we had a sub-zero model
642 side-by-side installed. So far, it is everything we expected, but
I have an "Is this normal?" kind of question. Every time the freezer
door is opened and then closed, a vacuum is created by the warm air
contracting as it cools. The air that equalizes it enters through the
main seal around the door making a hissing noise for 15 to 30 seconds
during which time, the door can't be opened. I am impressed that the
freezer is sealed well enough to cause that to happen, but I would
think sub-zero would have added some sort of check valve to control it
rather than having it hiss at you for 30 seconds. The manual has a
"noises that are normal" section, but doesn't describe this. Is there
something that got blocked off during installation that I should open
up? The installers mumbled something about "That's to dehumidify the
moist air that entered the freezer while the door was open", but that
doesn't make a lot of sense to me.

One more detail. About 20% of the time, a gurgling sound is made in
addition to the air entering through the seal as though air was also
entering through the defroster drain line.

Thanks,
Pat