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Old 09-13-2012, 05:24 PM   #1
scone
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I just installed a fancy new 7 cu. ft. freezer to use as a full time fermentation fridge. It's got 6 gallons of lager in it fermenting at 51F. The freezer seems to cut on every 45 minutes or so, but only for 3 minutes. I've got the tolerance set at 1C, should I raise it to get a longer duty cycle, or is it ok for the compressor to run for such a short amount of time?



 
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Old 09-13-2012, 05:29 PM   #2
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Not sure if that's a problem. My freezer kicks on for about five minutes every hour or so.


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Old 09-13-2012, 05:32 PM   #3
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My gut feeling says that 3 minutes run time is fine. It's more of a problem when it's only been off for 3 minutes and tries to kick back on.
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Old 09-13-2012, 05:41 PM   #4
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IIUC, the off time between runs on the compressor should be at least 5 minutes. More is better. sounds like you are running that compressor to death to get it to keep up with your 1 degree differential.

I have mine set to allow a 3 degree swing from setpoint, and have a fan circulating the air inside the box, and the compressor runs twice a day for about 10 minutes.

 
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Old 09-13-2012, 06:16 PM   #5
scone
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Quote:
Originally Posted by GilaMinumBeer View Post
IIUC, the off time between runs on the compressor should be at least 5 minutes. More is better. sounds like you are running that compressor to death to get it to keep up with your 1 degree differential.

I have mine set to allow a 3 degree swing from setpoint, and have a fan circulating the air inside the box, and the compressor runs twice a day for about 10 minutes.
Methinks you misread my post. My time between runs is ~45 minutes. I'm more concerned about the short "on" time.

 
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Old 09-13-2012, 06:24 PM   #6
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Quote:
Originally Posted by scone View Post
Methinks you misread my post. My time between runs is ~45 minutes. I'm more concerned about the short "on" time.
Maaaaybe, if all it takes is 3 minutes to get the degree change back, then so be it. It's short cycleing the down time that trashes the compressor.

Still, a 3 degree change (I think) is negligible.

 
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Old 09-13-2012, 06:28 PM   #7
scone
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I've never quite gotten around to installing a thermowell on anything, so I don't really know the effect of my temp swings on the fermentation. Does a three degree shift still result in stable fermentation temperatures? My swing is set to 1C, but in reality it's more like 1.6C since the temp keeps dropping even after the compressor shuts off for a little while. I do try to insulate the temperature probe against the ambient temperature by taping it to the fermenter and covering with bubble wrap....

 
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Old 09-13-2012, 06:29 PM   #8
jeepinjeepin
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Quote:
Originally Posted by scone
I've never quite gotten around to installing a thermowell on anything, so I don't really know the effect of my temp swings on the fermentation. Does a three degree shift still result in stable fermentation temperatures? My swing is set to 1C, but in reality it's more like 1.6C since the temp keeps dropping even after the compressor shuts off for a little while. I do try to insulate the temperature probe against the ambient temperature by taping it to the fermenter and covering with bubble wrap....
Neither have I. My probe is under a piece of foam taped to the side of the carboy.
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Old 09-13-2012, 06:37 PM   #9
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Quote:
Originally Posted by scone View Post
I've never quite gotten around to installing a thermowell on anything, so I don't really know the effect of my temp swings on the fermentation. Does a three degree shift still result in stable fermentation temperatures? My swing is set to 1C, but in reality it's more like 1.6C since the temp keeps dropping even after the compressor shuts off for a little while. I do try to insulate the temperature probe against the ambient temperature by taping it to the fermenter and covering with bubble wrap....
Ahhh. I always forget I have an in-fermenter thermowell.

 
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Old 09-13-2012, 06:41 PM   #10
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Also, my five minute every hour or so time is on a keezer with just a wood, no insulation, collar and the probe is just measuring air temp. My fementation fridge, where I tape the probe on the side of the bucket and insulate with foam, doesn't come on that often, maybe every couple of hours.


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