I’m testing out my temp contoller on my mini fridge to dial in the settings. One thing I had a question about is compressor delay. Its default setting is 3 minutes and can be adjusted to a max of 10. I remember reading in mini fridge manual that if the unit is unplugged or losses power you have to wait 3-5 minutes before you turn it on again. So should I change the setting to 5 mins to be safe? It seems like adjusting the temp swing value would also help reduce the chance of a compressor cycle before the delay. Another thing is if I only have a fridge plugged in and no heating device should I adjust the set temp higher or adjust the swing value to compensate.
I’d set the short cycle protection to 5, if that’s what the manual says…
You’ll have to play with the cooling settings, but attach the probe to a carboy filled with water so it’s more like a real fermentation. Temps swing too easily in an empty box. My controller let’s me control how far off set point the compressor turns on, and how close when it turns off. I see that when the compressor turns off, the temp continues to drop for a few more minutes. The goal is to minimize how much you overshoot the target temperature. My compressor comes on a 1 degree over set point, and turns off at 0.8 over set point. The heater comes on 1 degree under set point, and off at 0.5 under. Minimizing overshoot becomes important when you do add a heater, because you can end up ping-ponging between cooling and heating, which seriously wastes electricity.
For a heater, I use a <$20 heating pad from CVS. Look for the cheapest one, it needs to have a real switch, that you can leave in the on position. The higher end ones have on buttons that you have to press. It still has a 2-hour auto-shutoff, but mine typically never runs for more than 30-40 minutes. Pet lizard heaters are the same, but cost about 2x. Beer heater mats are also the same but cost even more. It’s all the branding; the more niche the market, the more the cost.
Awesome thanks for the info. I was just testing it on the mini fridge but I have a full size fridge that I’m in the process of finishing. I did also notice the temp keep dropping a few degrees after compressor turned off. Again I was just going by air temp like you said and not fermenting wort or liquid temp. I think my controller will only adjust temp difference for both heating and cooling. I set the compressor delay to 5 and temp difference to 2 degrees for now. Do you insulate the probe side that isn’t touching the carboy from the ambient air?
Yes, sort of. I used duct tape and cotton to make something that looks like like a big grey band-aid for each of my carboys/buckets. The probe slips in between the pad and the glass/plastic. It’s better than nothing, and I could probably do better, but it seems to work OK. I’ve thought about rigging a thermowell, but I think I’ve reached the point of diminishing returns, and it would be more to sanitize.
For your burn-in test with the mini fridge, if the probe is water proof, stick it in a 2-liter bottle filled with water. It will give you a much more stable test.
Try a bungee cord & a large sponge to put the probe under…
1 Like
When I used carboys it was a piece of packaging foam secured with an ace bandage. I hated the tape residue look. 
After all the work I put into making the doors for the fridge I found the missing lower fridge hinge. I was carrying it back down to the basement from outside and I heard something fall out from underneath. But having already thrown out the freezer door for a temporary fix I jammed a 1" piece of insulation in the freezer opening. Since the opening is angled the piece is super snug. I might put another piece of 1" over it and use some foil tape on the edges.
Anyone know if the ITC 1000 temp probe is waterproof. It looks rubberized but I don’t want to risk it.
