Hi fellas I have a few questions. I recently got a inkbird itc 308 temperature control. I’m trying to get my freezer to stay at 68. I set up the heating and cooling differential to 1F with my compressor relay at 3 minutes. I attached my probe to the side of a big glass of water with foam to insulate it. Freezer is set to minimum temp. My temperature takes a very long time to get to 68F, then the compressor shuts off at the set temp but will continue to cool and overshooting to about 61F so I’m constantly getting the alarm going off. What am I doing wrong? Cheers and thanks for any advice.
Until the liquid temp stabilizes expect longer run-time. The basics: When you set 68 the compressor doesn't see that . . . only that the temp probe is telling it that temp is too warm and to run. It puts out something like -20 degree air until the entire glass of water is equalized to the set temp (68). So the interior of your unit is probably sub-zero, that's why the relatively small glass of liquid continues to drop in temp. Once it's liquid is stabilized it should have much shorter run times and the interior will be at or slightly below set temp. Nothing happens fast when chilling liquids. A few times I've put a five gallons of 70 degree liquid in a freezer set at 38 . . . it took over 24 hours to bring the temp down. A better test is to put five gallons of liquid in your unit (or whatever size your primary is) and let it stabilize. Also, I would be cautious of using a compressor cycle time of 3 minutes. You really don't want the compressor cycling every 3 minutes (mine is set to maximum of 10). This will not affect the temp of your wort/beer. In ten minutes you won't see 5 gals increase any significant amount. Ideally you want your freezer to cycle much like your fridge, not much more than once an hour (lots of variables here). It will be more efficient if you fill up any extra space with buckets of water (or bottles of beer). It's the air leaking out that's inefficient, once stabilized any liquids tend to retain their temp and overall less run-time.
Check out post #3 by @PortLargo in the following thread and see if that helps. https://www.beeradvocate.com/community/threads/fermenting-temps-fermometer-accuracy.576635/ edited: I see PortLargo is quick on the draw. Good stuff from that guy.
How big is your freezer? Can you put more mass in it? By minimum temperature, do you mean its warmest or its coolest temperature? Also what is the temperature when it is set to that without the inkbird attached? You need to figure out how to balance the system and need to learn what the variables you are playing with are. If you have the temp probe insulated to the point where the freezer has to cool off a lot more so the insulated probe will reach the desired temp, then yeah the rest of the freezer will be cooler and slowly cool the water more. Additionally, 1 degree is hard to hold with this kind of set up in my experience. Do you have a heat source you can add to help the temperature not under shoot? I bought a cheap heating pad to use in mine, and can typically maintain a +/-3 degree swing from my target temp.
My freezer is about 5ft, minimum as in warmest. The probe is insulated but not overtly so. I’ve never thought about the heat pad but that sounds like a good idea. Thanks for the insight bud.
I added more thermal mass last night and set the relay to 10 and this morning it seems to be workin, will update to see if it continues to work. Thanks for the help!
