It’s probably just defrosting during those times. Your freezer should spend the better part of the day in the -2 to +2 range, but if it goes up to 20 or 25 then quickly drops back down an hour later either once or twice a day, I wouldn’t be concerned.
(ETA, an hour does seem like a long time for a residential freezer, our commercial reach ins only deforst for 30-45 minutes twice a day, OTOH, they use either hot gas or electric defrost, a residential probably either uses an air-over method or electric but not quite as blazing hot as our defrosters get.)
I’ve been datalogging and have periods of time where it’s over 0 for almost 80 minutes, with 20-30 minutes of that time over 20f.
The thermometer we’re using is specially built for use in a freezer. The temp on it doesn’t change just cuz we open the door a few times. It’s wireless so we don’t have to open the door to check the temp. It’s got an alarm that goes off when it goes over 0 degrees, and says that the temp should be between -20 and 0.
It won’t change the displayed temp just because the air temp changed … it takes several minutes for its temp to change, same as food and other stuff. So for it to be over 0 for 80 minutes, the air temperature must have been over 0 for longer than that.
So it sounds like something is definitely wrong with the freezer.
It’s so difficult to find good information about this online, or from talking to service technicians, or from talking to the service guys at Sears. I get different info from all of them - some say defrost is 20 minutes in this model of freezer, some say it’s 10 minutes, some say it “varies” depending on how much stuff is in the freezer.
This isn’t the kind of thing I can demonstrate for a technician - they’re going to have to take my data log at face value.
When this was discussed earlier, I put a data logger in my freezer to see what it was doing. It normally regulates the temperature to about 0 degrees Fahrenheit. When a defrost cycle starts, the temperature rapidly climbs to 42 degrees in about 20 minutes, stays at 42 degrees for about 6 minutes, and then cools down back to 0 degrees in about 45 minutes.
And I assume that your freezer keeps your food good for the extended periods of time most people expect from their freezers?
If you put food in there with an expiration date, and you haven’t opened the package, the food is good up until the expiration date (even if it’s 6 months or 1 year from when you bought it)?
I suppose it’s possible something other than the temperature fluctuation I’ve noticed is wrong with my freezer. Or maybe, as one service technician stated, my expectations are too high. I thought if I put something in with an expiration date in June 2009, that 3 weeks later (in October 2008) it wouldn’t be so badly frostbitten that it’s inedible.
Check the seal. Close the door over a dollar bill and try to pull it out, if it offers some resistance, you’re good, if it pulls right out, that’s bad. Work your way all the way around, if anywhere you go it just slips out, the seal needs to be replaced.