I had a new Danby chest freezer hooked up to a Ranco Duel Staged temp control set to 68. It worked great while it lasted, but the freezer crapped out on me after 10 months. I just got a replacement and I am curious if anyone that uses chest freezers for fermentation chambers have any tips for how to keep it running longer with less wear and tear on the compressor. Should I unplug it when it’s not in use to save the motor?
My guess is that you got a bad one. I am using chest freezer as keezer with a love temp controller, most set to 39 degrees. (in theory it runs more than yours, and is always on). It is almost 5 years old. My previous chest freezer was bought cheap off craigslist, and that one only lasted 3 years.
The only thing that I can think of is if the freezer clicks on and off more often to keep it in a narrower temp range than I would need for my application. I don’t know if you can set a minimum cycle time or a wider temp range with the Ranco.
I think that unplugging when not in use is always a good idea, however…especially if it cycles often to stay within a degree or so of your set point.
You want to make sure that it doesn’t unnecessarily short cycle by having the controller run a reasonable length of time each time it runs and have the timing not permit a quick start up by requiring a greater temperature drop of say 2-4 degrees. Mine was factory set to avoid this, but mine are the blue Johnson A419 model:
I suspect your controller will allow for this adjustment as well, but I have not used the Ranco.
Hmm you might need to fix this
Thanks for the feedback. I had it set up to have a fermwrap heat pad go on when it reaches 67 degrees, and the freezer to turn on when it hits 69 degrees with the probe inside a thermowell.
Not sure you need the heat. I use a chest freezer and dual temp controller as well with a 2 degree variance. When the temp warms the unit kicks on and chills to set point as designed.
Perhaps adding the heat made the temps fluctuate more frequently and caused the unit to cycle more frequently than needed.
This +1. You have a very tight temp window of 68 +/- 1 degree. This means that either the cooling or the heating overshoot, then it yoyos back and forth and short cycles your freezer compressor. In the winter, plug in the heating cycle. In the summer, plug in the cooling cycle. Set your hysteresis to +/- 2 degrees.
Corrected - thanks Euge. Damned iPad always goofs up for me on copying stuff…I know, it’s my own dang fault.
Do you wrap the fermentor with the ferm wrap? I wouldn’t. I use a heat pad simply taped to the back wall of the chest. I’ve had no problems.
How big is the chest? I can tell you that my 14cf Maytag works like a champ but my little freezer that I use for lagering does swing too cold by a couple degrees.
It was chilly a few times this past Winter and my CF’s dropped below ale temps so I just put a bottle of hot tap water in the chamber once or twice a day and it brought temps into line.
BTW the bottle(s) was the 1.75L glass handle type but I bet a growler would work. Idea was the the thick glass is a poor conductor of heat…
If you’re measuring air temperature in the chamber, you could move the thermometer to measure wort temperature - either with a thermowell or by taping it to the side of your fermenter and adding a little insulation over it. The temperature of the wort will swing much more slowly and avoid short compressor cycles. And anyway, that’s the temperature you’re really concerned about.
He is using a thermowell, so he’s measuring beer temp, not ambient air temp.
A 1 degree differential should be fine. i have an similar setup (chest freezer, thermowell, dual stage controller, fermwrap wrapped around a carboy) with a 1 degree differential, and I’ve gotten 10 years of brewing out of my freezer so far.
I think your last freezer was just a lemon. Or maybe my freezer is some sort of prodigy? But 10 months for a brand-new freezer seems really poor.
Maybe your freezer is in a bad spot. Is it crammed into a tight space, or a really dusty location? The compressor motor does need reasonable ventilation.
I have the ferm wrap loosely around the carboy. I have brew haulers on my carboys. The freezer is 7.1 cu. I had a brew going pretty continuously throughout the year so it was constantly toggling between 67-69 degrees, but that’s the purpose of the temp control chamber right?
I have the chest freezer in the garage and here in Northern CA the temp can fluctuate to very warm/hot days to cool to very cold nights, so I have the fermwrap to account for the temp swings when we have an 80/90 degree day and a 50 degree night. Maybe I need to widen the variance.
I don’t think it is in a bad spot, but it is in the garage which I wouldn’t think should be an issue because I have a stand up freezer and a beer fridge in there too that both work fine. Do you have your’s in your garage, or in a spot that has more consistent room temperature?
I find heating during day and night swings isn’t needed at all. In the freezer, with the amount of mass in the fermenter coupled with the yeast activity, the temp shouldn’t really drop more than a degree. I only use heat when the temp is below my target for most of the day.
Yup, looks like you’re doing great.