New Giveaway - Wort Monster Conical Fermeneter!

Home Brew Forums > Home Brewing Beer > DIY Projects > Guide to set internal chest freezer thermostat to >32F; Eliminate external control




Reply
 
LinkBack Thread Tools Display Modes
Old 06-06-2011, 02:36 PM   #11
Brennan
Feedback Score: 0 reviews
Recipes 
 
Join Date: Oct 2010
Location: Dallas, TX
Posts: 14
Default

Would this work on refrigerators as well, to get them up to 65-68 degree range?



__________________
Brennan is offline
 
Reply With Quote Quick reply to this message
Old 06-06-2011, 03:31 PM   #12
microbusbrewery
Senior Member
Feedback Score: 0 reviews
 
microbusbrewery's Avatar
Recipes 
 
Join Date: Jan 2011
Location: West Jordan, UT
Posts: 1,040
Liked 70 Times on 57 Posts
Likes Given: 42

Default

subcribed



__________________
microbusbrewery is offline
 
Reply With Quote Quick reply to this message
Old 06-06-2011, 04:03 PM   #13
gregkeller
Feedback Score: 0 reviews
Recipes 
 
Join Date: Feb 2011
Location: Westwood, NJ
Posts: 177
Liked 3 Times on 3 Posts
Likes Given: 3

Default

Alright, so everyone talks about the accuracy of maintaining a temp with an external controller, seems the digital ones keep the temp accurate to within a degree or so, and the analong ones within 4 degrees. How accurate are the internal thermostats of a freezer? I'm assuming they aren't nearly as accurate, because it just needs to keep stuff freezing, so if there is a big variation in temps, then it's not a huge deal because stuff isn't going to be melting/defrosting. But when we want it to stay around 40, is the internal temp gonna swing too much? I'd imagine that even if the internal temp swings a few degrees the temp of the beer in the kegs will not because of the thermal mass of a few 5 gallon cornies. Any ideas?

__________________
gregkeller is offline
kydan47 Likes This 
Reply With Quote Quick reply to this message
Old 06-06-2011, 04:59 PM   #14
JuanMoore
SACD
Feedback Score: 0 reviews
 
JuanMoore's Avatar
Recipes 
 
Join Date: Oct 2009
Location: The Old Pueblo
Posts: 15,526
Liked 3179 Times on 3087 Posts
Likes Given: 18

Default

Quote:
Originally Posted by gregkeller View Post
Alright, so everyone talks about the accuracy of maintaining a temp with an external controller, seems the digital ones keep the temp accurate to within a degree or so, and the analong ones within 4 degrees. How accurate are the internal thermostats of a freezer? I'm assuming they aren't nearly as accurate, because it just needs to keep stuff freezing, so if there is a big variation in temps, then it's not a huge deal because stuff isn't going to be melting/defrosting. But when we want it to stay around 40, is the internal temp gonna swing too much? I'd imagine that even if the internal temp swings a few degrees the temp of the beer in the kegs will not because of the thermal mass of a few 5 gallon cornies. Any ideas?
What you're referring to is the hysteresis of the thermostat. With the external controllers you're able to set the hysteresis yourself to keep temp swings to a bare minimum. From what I gather most modern fridges have a hysteresis of 6-10F that cannot be easily altered. I'm not sure but I think freezers usually have an even larger hysteresis. IMO this is probably ok for a keezer where precise temp control is less of an issue, but not so great for fermentation chambers. As always, YMMV.
__________________
JuanMoore is offline
 
Reply With Quote Quick reply to this message
Old 06-06-2011, 05:41 PM   #15
howabouttheiris
Feedback Score: 0 reviews
Recipes 
 
Join Date: Nov 2009
Location: Austin, TX
Posts: 231
Liked 2 Times on 2 Posts

Default

Is this true of the standard Walmart/HomeDepot freezer?
Would think that a digital control with a thermocouple would be cheaper now than mechanical controls....

__________________
howabouttheiris is offline
 
Reply With Quote Quick reply to this message
Old 06-06-2011, 07:04 PM   #16
ajwillys
Feedback Score: 0 reviews
Recipes 
 
Join Date: May 2008
Location: Holly Springs, NC
Posts: 1,308
Liked 21 Times on 19 Posts
Likes Given: 32

Default

I agree, hysteresis would be important for fermentation but in a keg its really not that important. If your temps swing from 37-43 degrees, 5 gallons of beer inside a steel keg is not going to change its temperature much, if at all. By the time the beer starts to noticeably warm or cool, the fridge temp is swinging the other way, counteracting it. The result is it will probably stay at a pretty tight average of the two extremes. Personally, I have mine set at 4 degrees with my Ranco, simply to reduce the cycling.

__________________
ajwillys is offline
 
Reply With Quote Quick reply to this message
Old 06-07-2011, 02:32 AM   #17
AssistantBrewer
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2011
Location: Littleton, CO
Posts: 8
Liked 17 Times on 2 Posts

Default

Wow, this thread seems to have generated a lot of interest.

Quote:
Originally Posted by carrotmalt View Post
So looking at the diagram, it looks like I'd be loosening (lefty loosy) the screw to get it above freezing right? In your experience, how many turns should I start off with for my first stab at 40 degrees? I'd love to not have to buy another controller for my keezer build!!!
The direction you turn is dependent on the particular thermostat you have. It could be left or right. The diagram is just for the concept. Here is one way to find out; If the freezer is at temperature and the compressor is off, unplug the unit and turn the screw a few turns in each direction and listen for the thermostat relay to click on. When it does you know the direction you were turning when it went on makes it colder.

Quote:
Originally Posted by Brennan View Post
Would this work on refrigerators as well, to get them up to 65-68 degree range?
Absolutely. I used this method for a long time on my fermentation fridge (dorm style fridge) to ferment Kolsch during the summer.

Quote:
Originally Posted by gregkeller View Post
Alright, so everyone talks about the accuracy of maintaining a temp with an external controller, seems the digital ones keep the temp accurate to within a degree or so, and the analong ones within 4 degrees. How accurate are the internal thermostats of a freezer? I'm assuming they aren't nearly as accurate, because it just needs to keep stuff freezing, so if there is a big variation in temps, then it's not a huge deal because stuff isn't going to be melting/defrosting. But when we want it to stay around 40, is the internal temp gonna swing too much? I'd imagine that even if the internal temp swings a few degrees the temp of the beer in the kegs will not because of the thermal mass of a few 5 gallon cornies. Any ideas?
One clear advantage of a digital thermostat is that you can set it where you want it without trial and error. The disadvantage is added complexity in wiring and cost. For my keezer once I've set the temperature I forget it. The ability to control "deadband" or hysteresis to 1 degree is unnecessary, IMO. The mechanical thermostats do have a several degree hysteresis. The reason is the manufacturer understands that several degrees of hysteresis prevents the compressor from rapid cycling thereby saving on the electrical bill and increasing the life of the compressor. Remember the volumetric heat capacity of air is about 1/3000 that of water so while the ambient air temperature in the freezer will vary by several degrees a corny (or even 12oz bottles) will vary relatively little. I see less than a degree of fluctuation in my keezer with a floating thermometer in a 12oz glass of water but around 5 degrees in the air temperature.

Quote:
Originally Posted by JuanMoore View Post
What you're referring to is the hysteresis of the thermostat. With the external controllers you're able to set the hysteresis yourself to keep temp swings to a bare minimum. From what I gather most modern fridges have a hysteresis of 6-10F that cannot be easily altered. I'm not sure but I think freezers usually have an even larger hysteresis. IMO this is probably ok for a keezer where precise temp control is less of an issue, but not so great for fermentation chambers. As always, YMMV.
I have yet to see one with a 10 degree deadband. My experience has all been right in the 5 degree ballpark. Remember, 5 gallons of wort has a very high heat capacity and will likely fluctuate only a fraction of a degree even with a 10F deadband. Think how long it takes to bring it up to boil with XX thousands of BTUs under it. And yes, of course, YMMV

AssistantBrewer
__________________
AssistantBrewer is offline
2
People Like This 
Reply With Quote Quick reply to this message
Old 06-07-2011, 04:27 AM   #18
ftlstrings
Feedback Score: 0 reviews
Recipes 
 
Join Date: Mar 2008
Location: Salem, Oregon
Posts: 296
Default

I think I like this...

__________________

"I asked God for a bike, but I know God doesn't work that way. So I stole a bike and asked for forgiveness."

ftlstrings is offline
 
Reply With Quote Quick reply to this message
Old 06-07-2011, 04:34 AM   #19
Yuri_Rage
Gritty.
Feedback Score: 0 reviews
 
Yuri_Rage's Avatar
Recipes 
 
Join Date: Jul 2006
Location: Southwest
Posts: 13,863
Liked 574 Times on 357 Posts
Likes Given: 52

Default

Fantastic thread. I'm very interested to hear other success stories with this method.

__________________
Homebrewed Blog..........YouTube Channel .......... Shirts, posters, etc
Yuri_Rage is offline
burton178 Likes This 
Reply With Quote Quick reply to this message
Old 06-07-2011, 10:12 AM   #20
marzsit
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2009
Location: kent, wa.
Posts: 315
Liked 5 Times on 5 Posts

Default

been there, done that... depending on the thermostat design and where the sensing bulb is located, the results can be hit or miss. i had an old whirlpool chest freezer that was re-adjusted to work between 35-46 degrees, it was fine as long as the ambient temperature of the room was kept between 60-70 degrees. outside of that range, it was pretty unpredictable and would get too warm or too cold.



__________________
marzsit is offline
 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
External HEX Vs. Internal CoalCracker DIY Projects 20 03-01-2012 05:11 AM
Chest freezer: to bypass (or not) the thermostat paledragon DIY Projects 3 01-28-2011 02:01 AM
anybody know where to get a cheap external thermostat? kair DIY Projects 2 07-24-2010 09:23 PM
External T/stat for chest freezer ILOVEBEER DIY Projects 12 03-22-2010 06:34 AM
Temp Control For Chest Freezer PT Ray DIY Projects 0 01-19-2010 01:26 AM