Author Topic: Freezers for crash down  (Read 6080 times)

Offline Bevo

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Freezers for crash down
« on: February 24, 2016, 04:26:26 PM »
I'm using upright freezers with Ranco ETC's for the fermentation and subsequent crash. I have went through a few freezers now. Wondering what's failing in them. Has anyone else had problems with consumer grade freezers? I have even went as far as to buy an aftermarket heavy duty capacitor and start relay.

Thanks,
Bevo
« Last Edit: February 24, 2016, 04:37:20 PM by Bevo »

Offline brewfun

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Re: Freezers for crash down
« Reply #1 on: February 24, 2016, 04:39:23 PM »
Generally, the cycle time for beer is rather short. This isn't good for the compressor in the freezer.

One method to smooth out the cycles is to place the sensor bulb into a pint or quart of water. This acts as a buffer from air temp and lengthens the cool/rest cycles.

Make very sure that the door is fully sealing, too.
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Offline Oginme

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Re: Freezers for crash down
« Reply #2 on: February 24, 2016, 04:42:32 PM »
What are you using for a controller?  Most freezers are poorly designed for temperature control above freezing.  Constant cycling of the compressor on and off causes failure of the compressor fairly quickly.  A good controller will allow you to set a dead band and reset time so that you are not fighting constant on-off-on of the compressor.
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Offline Bevo

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Re: Freezers for crash down
« Reply #3 on: February 24, 2016, 04:56:50 PM »
Ranco Electronic Temperature Control I think model no. 111000

Offline brewfun

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Re: Freezers for crash down
« Reply #4 on: February 24, 2016, 05:05:54 PM »
Ranco Electronic Temperature Control I think model no. 111000

That unit has a differential of 1o to 30o F. Setting the differential to 15 degrees or so should make a big difference. At least 5, if you take the water buffer idea I gave.
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Offline Oginme

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Re: Freezers for crash down
« Reply #5 on: February 24, 2016, 05:24:53 PM »
I tape the probe directly to the carboy with insulation on the outside.  This has helped greatly with reducing the cycling of the compressor.
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Offline StatsnBrew

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Re: Freezers for crash down
« Reply #6 on: February 25, 2016, 10:26:15 AM »
If you insert the Ranco probe into a thermowell immersed in the wort in the fermentor you will eliminate the short cycling, lengthen the life of the freezer and control the temperature of the wort itself rather than the air mass inside the freezer. 

I use a two stage Ranco with one stage controlling the freezer power and the other stage controlling a FermWrap heater.  This system has worked well for me with plastic carboys as well as stainless conicals. 

I set both stages to the same temperature thereby controlling my wort temperature to +/- 1° F.  For example, if fermenting at 65° F I set both the heat and cool stages to 65°. This way the heater kicks on if the temp drops to 64° and goes off again when it hits 65°.  The freezer comes on if the temp goes to 66° and goes off again when the temp drops back to 65°.  The big thermal mass of the wort surrounding the thermowell and the low power density of the FermWrap make this work very well.
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Offline twhitaker

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Re: Freezers for crash down
« Reply #7 on: February 25, 2016, 12:57:23 PM »
 I used to put the probe in a one liter plastic beer bottle full of water in the kegerator. Seal with foil tape. Basically  Immersion in a smaller version of the brew without sanitation or thermowell installation  issues.  It worked well. The compressor didn't cycle much. 

 BUT: Now for something you probably don't want to hear but you are by now realizing: cheap domestic freezers have no inherent designs  to drain the amount of condensation that builds up on the coils, when you convert it to a kegerator as they  are supposed to be kept frozen not above zero. So I have found the coils  failed from corrosion (pin holes)  draining the system of refrigerant, ruining the compressor.

 PS: I have some commercial refrigeration experience. There is a reason why fridges built for beer kegs and commercial keg coolers cost thousands of dollars more. Any long term keg cooler solution requires you to look further into the design of the commercial units and decide to go pro, or try and replicate,  or keep turning freezers into fridges which have a lot more internal design differences than just the control.
Evaporator and condenser coil material, shape, configuration, capacities, etc...

 I have  posted about this before  with pics but the majority disagrees and doesn't want to hear it. I have found a nice kegerator that was designed to keep beer kegs cold and it works fine for the past few years now and my old "converted"  kegerator is a  table now.
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Offline StatsnBrew

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Re: Freezers for crash down
« Reply #8 on: February 25, 2016, 04:18:10 PM »
Thanks for the tip on the possible failure mode, twhitaker.  You just triggered an a weekend inspection on my freezer.
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Offline Bevo

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Re: Freezers for crash down
« Reply #9 on: February 26, 2016, 05:59:47 PM »
Just wanted to say thanks for all of your replies and thoughts.

What make and model is the kegorator that you speak of?

Offline twhitaker

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Re: Freezers for crash down
« Reply #10 on: February 27, 2016, 09:30:09 AM »
 I picked up a 5.8 cu ft Danby keg cooler at a liquidation warehouse for half price. It fits a full size commercial keg, has reinforced steel floor and rack to support it with keg coupler, which I cut off and installed ball lock fittings. I can fit 3 corny kegs at 19 liters each and some bottles at once. The Evaporator coil is a self contained plate at back sealed  in anti corrosion coating. I also have an old frigidaire upright fridge that fits carboys and kegs and used to be my front tapped kegerator with a shank through the front door. I keep yeast and bulk hops in there as well . Both work flawlessly.

 The chest freezers to watch out for are the ones that have the evaporator coil, which is steel tubing, encased in foam behind the cabinet of the freezer. It wraps around inside the cabinet. You can't inspect it. It's sealed in there invisible to you. The only evidence of imminent failure is rusty water building up inside on the bottom of your kegerator. But even if you can't see it, over time the condensation is working against you because it cannot go anywhere it is trapped inside the foam insulation against the steel tubing. Corrosion is imminent. Steel tubing with trapped moisture against it constantly is not going to last. If you see a coil on the back or outside the unit, that is the CONDENSER coil . That is differrent and changes the gas freon back to liquid before it gets to the compressor.Thats why these units are cheap. There is no need for better materials or configuration as the original working design of these units has these coils constantly frozen; building up frost but not water. It is also very in-efficient to run a unit designed for sub zero temperatures above zero from a refrigeration design point of view. Changing the evaporator design temperature  affects the way the freon changes state from a liquid to a gas, straining the system - i.e.- the compressor. If you study making a small refrigeration system from scratch,  you will see how although similar to the casual observer,a freezer and a fridge are two very different animals.
A converted kegerator  is not a permanent solution to keg cooling. I know it feels great to make one though,I've  Been there; but this is a case of a little knowledge actually being worse than no knowledge. 
On tap: 1/2keg cream ale with corn grits
             1/4 keg-  Trappist Quad Ale w/ oak
Day 10 primary: West Coast I.P.A. with homegrown columbus hops 46 liters