Keezer cycle time

What are people's keezer cycle times seem to be averaging? I have a 7cf keezer I just finished and got my temp controller on last night. I have the probe submerged in a glass of water to help with the swings. Just wondering if my cycle times are average of if I need to make some tweaks to my setup. So let's here what others are saying....how long between freezer cycles are people seeing?

I just set mine up as well with a digital temp gauge. Mine doesnt seem to be turning on any more than every 20 or 30 min or longer. It is in the garage and it is in the low 40's where I live (I have my temp set at 40 degrees). Therefore, I think this may be slightly abnormal (as in, I'm going to see what happens in the middle of the summer). What is yours cycling at?

So yours turns on ever 20-30 min?

I think it may be longer actually. I think that was soon after I set it up and was tinkering with everything often. I have been looking at it tonight and I do not think it has been on for like an hour or so. But like I said, its cold outside and my keezer is in my garage.

I have my temp controller set at 5c with a 2 degree differential. Seems to be losing a degree ever 30-45 min so is kicking the freezer on every few hours. Mine is in my house at 70. Does this sound reasonable to others? Or do I need to work some insulation issues?

I am actually surprised it is not running more often in a 70deg environment. Think about it though, the freezers are made to run pretty much continually. Sounds fine to me.

I figured it was okay, I was just curious to see what other people's cycle times were. I know most people also have a smaller differential set to .5 - 1.0, but I figured fewer cycles and the beer wouldn't change temp that fast in a keg....so there wouldn't (or shouldn't) be THAT big of a difference for a 1 degree more diff. Seeing as I lose a degree every 30-45 min, that isn't that big of a deal and if it adds a few years of running time to my freezer, well worth it.

if you have no mass in the keezer, it will cycle way more often.

get two kegs in there and it'll cycle a lot less

regardless, a 1-2-3-4 degree differential in air temp control won't really change the beer temp at all. it takes a lot of energy to get 5 gallons of liquid to move in temp.

Yeah, currently I have 2 kegs in there. I'm trying to maintain that at the very least. Ideally, I'll get 2 more kegs and have 2 on tap, 2 carbing naturally to fill the space.

Have a 20 cuft set at 39* in the house runs about every 45mins. for 5-7 mins with e-bay temp control

Sounds good. Thanks guys. I'll just take it that my freezer turning on every 2-3 hours for 10-15 minutes is well in the range of being fine. Just trying to minimize the work the freezer does to help it last as long as possible.

Thanks

Brewnoob1 said:

Yeah, currently I have 2 kegs in there. I'm trying to maintain that at the very least. Ideally, I'll get 2 more kegs and have 2 on tap, 2 carbing naturally to fill the space.

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carbing naturally, or carbed naturally? naturally as in yeast and sugar? that won't work too well @ 40° :cross:

Brewnoob1 said:

Sounds good. Thanks guys. I'll just take it that my freezer turning on every 2-3 hours for 10-15 minutes is well in the range of being fine. Just trying to minimize the work the freezer does to help it last as long as possible.

Thanks

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oh, yeah, that's well within the range. that's really good actually.

Pdeezy said:

carbing naturally, or carbed naturally? naturally as in yeast and sugar? that won't work too well @ 40° :cross:

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Sorry, carbED lol...thanks for catching that

motobrewer said:

oh, yeah, that's well within the range. that's really good actually.

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Awesome...that's what I was hoping. The freezer may be taking a little longer than the 15 min, but whenever I see it close to turning on, next time I check usually within an hour, it's already down to 3-4 and is off. So, the 10-15 min run time is a guesstimate.

I haven't timed mine, but a 5cf with two 1/2 full kegs seems to kick on every 30-45 minutes or so for 3-5 minutes and then shuts down. And I just have the temp probe measuring ambient air inside the keezer.

Building that keezer was the best thing I did last year. Although, my beer consumption has sky rocketed. Go figure.

Fly_Rodder said:

I haven't timed mine, but a 5cf with two 1/2 full kegs seems to kick on every 30-45 minutes or so for 3-5 minutes and then shuts down. And I just have the temp probe measuring ambient air inside the keezer.

Building that keezer was the best thing I did last year. Although, my beer consumption has sky rocketed. Go figure.

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I just tapped my first keg and it carbed up the other night...I anticipate my beer consumption may follow. And with no bottles lying around, the wife won't be able to referee as easily.

My digital temp probe is in a glass of water and I also have a temperature probe measuring ambient temp in the freezer. I am realizing that the ambient temp is not that helpful because of the vast difference in the temp of the air versus the temp of the kegs. If the lid is not opened for awhile (like over night), they read the same. I have heard of people taping the temp probes to the kegs. Maybe I will try that. I guess I originally wanted the extra probe to serve as a check on the digital controller. Not working too well at this point.

It always surprises me when people control their freezers using beer temp instead of freezer air temp. Water, which is what mostly makes up beer, has one of the highest heat capacities of any material meaning it takes a ton of energy to get it to change its temp. Air has a fairly small heat capacity, it will change temp quickly. If you stick your temp probe that controls your temp controller on your keg/fermenter, your freezer may cool to a temperature well below the temperature of your beer. In a large enough freezer, this could cause your beer to continue cooling past the desired temp then slowly creep back up to your target. By that point the temp in the freezer could be well above your target. While this may reduce cycle times, in theory, your beer temp would be more consistent if you put your probe in the freezer air, midway up and a good distance from the side. Maybe in practice this is wrong though, it seems everyone gravitates towards sticking the probe on the keg or in the fermenter. Personally, I put the controlling probe in the freezer or chamber air then another in/on my wort/beer then set the air temp a smidge above my target temp. Works like a charm with only a little babysitting in the first few days of fermentation.

Spintab said:

It always surprises me when people control their freezers using beer temp instead of freezer air temp. Water, which is what mostly makes up beer, has one of the highest heat capacities of any material meaning it takes a ton of energy to get it to change its temp. Air has a fairly small heat capacity, it will change temp quickly. If you stick your temp probe that controls your temp controller on your keg/fermenter, your freezer may cool to a temperature well below the temperature of your beer. In a large enough freezer, this could cause your beer to continue cooling past the desired temp then slowly creep back up to your target. By that point the temp in the freezer could be well above your target. While this may reduce cycle times, in theory, your beer temp would be more consistent if you put your probe in the freezer air, midway up and a good distance from the side. Maybe in practice this is wrong though, it seems everyone gravitates towards sticking the probe on the keg or in the fermenter. Personally, I put the controlling probe in the freezer or chamber air then another in/on my wort/beer then set the air temp a smidge above my target temp. Works like a charm with only a little babysitting in the first few days of fermentation.

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You make a good point about the thermal capacity of water v air. A good compromise would be to put the probe in a small volume of liquid (eg, a cup of water) to keep the freezer from coming on every time the lid is opened, while maintaning a more stable beer temp than if the probe were in a fermentor or against a keg.

Spintab said:

[...]If you stick your temp probe that controls your temp controller on your keg/fermenter, your freezer may cool to a temperature well below the temperature of your beer.[...]

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It appears the entire premise is based upon a malfunction as described above...

Cheers!

To the points above, I have my probe sitting in a glass of water to measure liquid temp, not air temp.

With that said, I made a few slight adjustments this weekend. The freezer now swings much slower. It runs for about 30min to an hour to bring it down to about 4 degrees Celsius and takes up to 6 hours before hitting 7 degrees to flip the freezer back on. I'm happy with it running only 4 times in a 24 hour period.

I have my probe in the air inside my keezer. Temp set at -2C with a 5C differential, so my temp range is -2C to 3 (28F - 37F) which keeps my beer around 34, and the keezer cycles every 45min or so for about 3 minutes.

scottland said:

I have my probe in the air inside my keezer. Temp set at -2C with a 5C differential, so my temp range is -2C to 3 (28F - 37F) which keeps my beer around 34, and the keezer cycles every 45min or so for about 3 minutes.

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If your on and off intervals are both accurate, your keezer must have a large compressor and terrible insulation. To have your temp rise by 9 deg F over 45 minutes is super fast. Even if I left my keezer open for 45 minutes it may not rise by 9 deg. To have it cool back down by 9 deg in 3 min is also insanely fast, especially considering the poor insulation. Putting your probe in a small container of water will reduce the frequency at which the keezer turns on. The 3 minute 'on' time is baffling. My 4 keg keezer comes on for 15 min every 3 hours, it's set at 40 deg F with a 2 deg swing.

I'll put a different spin on this. I don't have a keezer but I lager in a freezer so it's pretty much the same thing. My temp controller is an arduino so I've coded how it cycles. I set a target air temp, and a heating/cooling mode. Obviously it's in cooling mode for this. Heating if for my HLT. When the temp is above the target, it turns the freezer on for 30 seconds, once it's run for 30 seconds, it checks the temp every 10 seconds until the target temp is passed. Seeing as it's a 3cu.ft freezer, 30 seconds is usually enough to get the fluid running through the freezer and drop the temp below the target. A 30 second run usually drops the freezer air about 5 degrees, 4 of which happen after the compressor has already shut off. Pretty sure it cycles about once every hour and a half or so. I've never really timed it. As long as it's not cycling so fast that it's causing damage to the compressor I've never really cared.

Edit: Geez nevermind. That cycle was 15 minutes. I think the deal is the probe is too close to the inside wall of the freezer. Hah, it's probably holding the average temp to a degree or two. Oops.

Edit Again: No it needs a differential. Don't turn on until you're a (differential amount) past the target, don't turn off till you've passed the target. Unless the freezer is big it will always drop the temp enough by 30 seconds to shut down the compressor.

Yeah, I think I'm going to call mine in the sweet spot. 6hr average time to raise from around 4 degrees C to 7 when there it turns on the compressor. It then takes 30-45 min to bring it back down. My probe is in about 30-36oz of water. So average run time is around 4 times a day for less than 4hrs.

I bought a 14oz. tub of plumber putty, and put the temp probe in the middle of the putty. It's a good small thermal mass, and its not liquid so it doesn't spill. My keezer runs for probably 20 minutes every 1 1/2 hours. Now, I know thats not super efficient, but I have 4 taps 5 feet from the keezer so there is a well insulated line running from the keezer to where the taps are, and I made a custom top. I know there is some heat loss in my system, but that's the only way I can make it work. I don't think placing the probe in the air, is a smart thing when talking about a freezer. If I did that, the compressor would cycle for a few minutes at at time, and do it frequently. Nothing kills a compressor faster than that!

Of course, this thread is 5 years old, so don't know if anyone cares at this point!

It depends heavily on how you have the probe. I attach my probe to the side of a half gallon jug of water.

With the probe attached to the side of the jug with a layer of paper towels for insulation (but no tape covering the top and bottm of the paper towels so slightly open to the air) it cycles every 1.5 hours or so. I tested by doing the same thing but this time adding more paper towel insulation and also taping the top and bottom of the paper towels so no air could get in and it cycled every 2.5 hours. I decided to use option one since it barely overshoots the temperature too low this way. Option 2 overshot the temp downwards 2 or 3 degrees. Oh yeah and this is with it set to 35F with a 3F differential.

Taping to the side of a keg with more thermal mass would further increase the time between cycles but also the swing downwards. You just have to find the balance you like.

And actually now that this thread brings the topic back up its making me rethink my decision. Perhaps 1 or 2 degrees downswing is ok and worth more than the decreased life of your keezer with increased cycling. Then again when your temp is so close to freezing once your keg makes it to 35 and downswings 1 or 2 degrees the actual air temp is going to be below freezing. Not ideal. May call for more testing.

I should have mentioned, I have the probe inside the putty about 12 inches off the bottom of the keezer in a pipe, and its in the middle of the kegs, away from the walls. So, its really meant to represent the middle of the keezer. I also have a fan circulating in there, so the there aren't really any layering or pockets of different temps. I have found this to be a happy medium. I actually had an old keg that leaks, and I filled it with water and put the probe in the middle of that, hung from the top. I found I found that it maintained the same temps, but as you said, there were much longer times between cycles, and the cycles were much longer. I think I am at a good spot now.