STC-1000 In fermentation chamber constantly going from heat to cool - Home Brew Forums
Home Brew Forums > Home Brewing Beer > DIY Projects > Fermenters > STC-1000 In fermentation chamber constantly going from heat to cool

Reply
 
Thread Tools
Old 09-22-2012, 08:12 PM   #1
Chaddyb
Recipes 
 
Oct 2010
Minnesota
Posts: 175
Liked 7 Times on 7 Posts



So, I just got my STC-1000 wired up in my old chest freezer. Everything works as it should, it kicks the heat on, and the freezer on when it should. Ive been wathching it all day today as ive ben working out in the garage, the air temp in the garage is roughly 60 degrees. I have the controller set at 68 degrees, and the probe in a gallon jug of water. The unit always keeps the chamber within 67.5-68.5 degrees, so thats good I guess. The problem is, It will kick the heat mode on to bring it up, which it does, then the temp will creep up above the set range, and kick the coolong on, which brings the temp back down, but then it will creep down below the threshold and kicks the heat back on. This cycle seems to continue endlessly. It takes about an hour to swing the temp from one end to the other.

My question is, is this fairly normal? I have a ceramic heater for heat, and im wondering if its heating the air too quick, and getting it too hot? Its a 750 w unit with a fan. I might try to turn the fan off so it heats things less rapid too.

Also the chamber can fit 6 carboys in it, so its rather large.
__________________
Kegged: Grand cru, Ferocious IPA
Bottled: Java stout, Hanks hefeweizen, Grand cru
Primary: Chocolate milk stout, pumpkin ale, Belgian Wit
Secondary: Coffee brown ale
Next Up: ?

 
Reply With Quote
Old 09-22-2012, 09:29 PM   #2
krazydave
Recipes 
 
Aug 2010
Santa Clarita, California
Posts: 924
Liked 32 Times on 30 Posts


I've had the same problem. What I found works best is to use the smallest heat source you can. The small ceramic reptile heaters work great. I also leave a fan running inside at all times. This won't stop the overshooting on the cooling cycle but it will help the heating cycle.

Also I use a lamp dimmer on my heat source which is actually a 150w enclosure heater for an electronics enclosure. I work as one of the head support guys for those tvs that you see across the country on gas pumps and we use those to keep the systems warm when the outside temps drop too low. It's basically a heat sink with a heat coil built in that has a fan mounted on top. If I use that thing at full power, I'll overshoot my heat temp every time. So I have it cranked down to almost nothing and that seems to work the best.
At least my temp stays more stable that way and my freezer cycles a lot less.

 
Reply With Quote
Old 09-23-2012, 03:13 AM   #3
Chaddyb
Recipes 
 
Oct 2010
Minnesota
Posts: 175
Liked 7 Times on 7 Posts


I think I will have to try a different heat source, this one seems to overshoot it every time. I have heard the reptile heaters work good, I'm thinking about building a paint can heater as another option.
__________________
Kegged: Grand cru, Ferocious IPA
Bottled: Java stout, Hanks hefeweizen, Grand cru
Primary: Chocolate milk stout, pumpkin ale, Belgian Wit
Secondary: Coffee brown ale
Next Up: ?

 
Reply With Quote
Old 09-23-2012, 03:21 AM   #4
JuanMoore
Recipes 
 
Oct 2009
The Old Pueblo
Posts: 21,854
Liked 3676 Times on 3498 Posts


A gallon jug for the probe to sit in is a huge amount of thermal mass, which could also be contributing to the overshoots. Do you have anything in there besides that right now? It's generally not a good idea to run empty.
__________________
I'm trying to find some porn filmed by a dog wearing a GoPro. - SharonaZamboni

Hunter, when you get bored, will you put a taco in my elephant's hands for me? - Hat

 
Reply With Quote
Old 09-23-2012, 01:26 PM   #5
Chaddyb
Recipes 
 
Oct 2010
Minnesota
Posts: 175
Liked 7 Times on 7 Posts


Quote:
Originally Posted by JuanMoore View Post
A gallon jug for the probe to sit in is a huge amount of thermal mass, which could also be contributing to the overshoots. Do you have anything in there besides that right now? It's generally not a good idea to run empty.
No its empty other than the jug o water. I had the sensor hanging in mid air, and the fluctuation was much more rapid that way, the water takes it a lot longer.

The only reason I'm running it empty is to see how everything acts, and to try to fine tune things. Maybe I will fill a fermenter with water and try it out.
__________________
Kegged: Grand cru, Ferocious IPA
Bottled: Java stout, Hanks hefeweizen, Grand cru
Primary: Chocolate milk stout, pumpkin ale, Belgian Wit
Secondary: Coffee brown ale
Next Up: ?

 
Reply With Quote
Old 09-23-2012, 06:09 PM   #6
rwortman
Recipes 
 
Sep 2011
West Lafayette, IN
Posts: 5

That controller doesn't have as many options as one would like to see, but by increasing your differential, you should be able to minimize the constant switching you are seeing. What do you currently have it set at? If it is really low (1 or 0 degrees), your system will continuously run trying to stay at exactly the setpoint.

The rapid cycling will really decrease the lifetime of your compressor.

I'd recommend setting the differential (how far the temperature can swing from the setpoint) to 2 or 3 degrees and put the temperature probe in a gallon or half gallon of water. That temperature will swing faster than your beer assuming you have more than a gallon of it.

Also, you may disconnect the side that you don't need. If it is colder outside the chamber than you want it (or warmer), unplug the compressor (or heater). The ambient temperature will slowly change the interior temperature to its trigger point, where it will turn on the cooler or heater to bring it back to the target.

 
Reply With Quote
Old 09-23-2012, 06:17 PM   #7
pvtschultz
Recipes 
 
Feb 2010
New Berlin, Wisconsin
Posts: 457
Liked 8 Times on 8 Posts


I had the best control running with two full carboys, whether or not they were both full of wort. The added thermal mass really slows things down. I started with a 150W ceramic reptile heater but that was just way too big. I then found a 60W one and that one was better. Anymore, I just use the one that is going to be most likely needed. I really only need heat when the ambient temperature is below the fermentation temperature, otherwise I leave it unplugged during the remainder of the year.
__________________
Brewing: Amber Ale, Dunkel
Drinking: Sour Brown, Schlitz...
On Deck: Berliner Weisse, Spotted Cow Clone, CAP...
2016 Gallons Brewed: 10 :(
Gallons Brewed '11-'15: 319

http://www.homebrewtalk.com/f170/pvt...inally-298407/

 
Reply With Quote
Old 09-23-2012, 09:10 PM   #8
JuanMoore
Recipes 
 
Oct 2009
The Old Pueblo
Posts: 21,854
Liked 3676 Times on 3498 Posts


Quote:
Originally Posted by Chaddyb View Post
The only reason I'm running it empty is to see how everything acts, and to try to fine tune things. Maybe I will fill a fermenter with water and try it out.
It will behave completely differently with 5-15 gal of liquid in there. Freezers aren't designed to be run empty, and freezer manuals usually have strongly worded warnings advising against it. Not only are you not getting an accurate picture of how it behaves, you're also needlessly cycling the compressor and reducing it's life expectancy. You can prevent the temp overshoots without changing the temp differential by changing the probe placement (once you get some thermal mass in there). Since it sounds like this is a ferm chamber, I'd suggest taping the probe to the side of the fermenter of the most recently brewer beer, and then taping something over it to insulate against the ambient air a little (folded paper towel, piece of foam, rag, etc). This will give you very accurate temp control, eliminate your overshoot issue, but still give enough thermal mass close to the probe that opening the lid won't cause immediate changes. If you really want a permanent location for the temp probe, I'd suggest using a much smaller container of water, like a yeast vial, or 8oz water bottle.
__________________
I'm trying to find some porn filmed by a dog wearing a GoPro. - SharonaZamboni

Hunter, when you get bored, will you put a taco in my elephant's hands for me? - Hat

 
Reply With Quote
Old 09-24-2012, 12:36 PM   #9
pvtschultz
Recipes 
 
Feb 2010
New Berlin, Wisconsin
Posts: 457
Liked 8 Times on 8 Posts


The best place for the probe is taped to the side of a carboy with insulation like a sponge (or inside it) giving you a direct temperature measurement of the wort temperature. The wort will heat/cool much slower than a baby food jar full of water and will reduce the freezer compressor cycling.
__________________
Brewing: Amber Ale, Dunkel
Drinking: Sour Brown, Schlitz...
On Deck: Berliner Weisse, Spotted Cow Clone, CAP...
2016 Gallons Brewed: 10 :(
Gallons Brewed '11-'15: 319

http://www.homebrewtalk.com/f170/pvt...inally-298407/

 
Reply With Quote
Old 09-24-2012, 09:51 PM   #10
Chaddyb
Recipes 
 
Oct 2010
Minnesota
Posts: 175
Liked 7 Times on 7 Posts


Cool, thanks for the suggestions, I will try to throw a couple fermenters in there and move the placement of the probe. Then I can see how this thing reacts. Thanks again.
__________________
Kegged: Grand cru, Ferocious IPA
Bottled: Java stout, Hanks hefeweizen, Grand cru
Primary: Chocolate milk stout, pumpkin ale, Belgian Wit
Secondary: Coffee brown ale
Next Up: ?

 
Reply With Quote


Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Heat source for fermentation chamber smittygouv30 Fermenters 26 07-17-2012 07:34 PM
How long did your fermentation chamber take to cool? Newguy3420 Fermenters 10 06-05-2012 09:37 PM
Guess I'll be looking for a better way to heat my fermentation chamber G-Hog Fermenters 7 02-14-2012 10:54 PM
Will my old Absocold dorm fridge work to cool a fermentation chamber? Hoppopotomus Fermenters 6 11-08-2011 08:53 PM
Adding heat to fermentation chamber thermostat AJC16 Fermenters 1 08-05-2010 09:58 PM


Forum Jump