Is my temp controller possibly defective?

[Metallion66]

First off, hello everyone. I've been lurking here a bit but haven't really posted. I'm still new to homebrewing, barely on our third batch. And I recently purchased a freezer and a temp controller (for fermenting but will also turn it into a keezer soon).

Anyways so I'm at work right now so can't really spend time to call the homebrew shop I bought the controller from so thought I would ask here. I'm thinking this thing is either defective, or I am some how doing something really wrong.

I am using a Brewers Edge Digital Controller II. I have it set for 69 degrees, with a 3 degree differential. However for some reason the display shows my temp going from 69 to 55 sometimes. And it seems to go back and forth at least once an hour. And other thermometers I stuck in there seem to agree with the temp the controller is reading. I've kept an eye on my beer thats fermenting, and luckily that has stayed pretty steady. But it still bugs me that the temp is dropping so much, or at least reading that it is.

I tried putting the sensor both in a glass of water, and right now I just have it reading the air. What boggles my mind is that it gets colder. I mean, if I had a gap of air or something, shouldn't the freezer if anything be getting warmer. Any idea what could be causing this? Or should I just straight up see about getting it exchanged?

All your thoughts are very much appreciated.

 

[LordUlrich]

My first thought is you should have the probe measureing the temp of the beer, afterall that is what matters.
As far a what could be causeing your situation the temp of the air may vary quite a lot not a real big deal it happens. The other possibility is you could have an anti-short cycle feature. This is a good thing it protects your compressor as frequent on and off cycles are bad for them. So your controler may have a minimum on time and that is why you are over cooling.
As a solution tape the probe to your fermenter with some styrofoam insulating it from the air and see what happens

 

[Psych]

Test the probe itself first, if it's meant to read the air temp then just leave it beside one or two other thermometers that you trust and see how far off it is. Adjust as needed, if possible. Or, better yet, put a bunch of ice cubes in a bowl of cold tap water, let it sit for 5 mins or so and measure the temp of the water. Should be right at/near freezing, or just above.

Or throw it in boiling water and see if it measures ~212 or so. Be sure your thermometer can measure that high though, don't want to void the warranty.

Past that, you can maybe put a copper jumper (ie: bare wire) between the thermometer probe leads on the device itself, like where your thermometer leads back to on whatever device this is. Then see if it measures ambient temps properly.

Check for excessive warmth on the device itself, perhaps some bit of it is overheating?

 

[Metallion66]

Thanks for the responses.

My controller does have an anti short cycle feature on it. But if it's taking longer to turn back on, wouldn't the freezer warm up as apposed to cool down? That's what doesn't make much sense to me. I'll try the styrofoam thing tonight when I get home. As well as testing the temperature in some ice water.

I have a thermometer on my fermenting bucket which is how I've been able to tell it seems to be doing alright. And overall as long as my temperatures in fermentation stay good, and my temps when its' in keezer mode stay good, I guess I could really care less what the controller reads. It's just a pain cause I over payed for this (wanted it that day instead of ordering one) and I thought the readings would be more accurate.

Thanks again. I'll go talk to the guys at the homebrew shop if if it's still acting wonky in a day or two.

 

[Catt22]

There's nothing wrong with the controller. The air temp will always swing. Do attach the probe to the fermenter and cover it with some type of insulation. Adjust the set point to 1 degree. Set the anti-short cycle delay to at least 5 minutes and preferably more. This should get you going in the right direction and you can adjust from there. I recommend installing a small computer fan to circulate the air.

 

[Catt22]

My controller does have an anti short cycle feature on it. But if it's taking longer to turn back on, wouldn't the freezer warm up as apposed to cool down? That's what doesn't make much sense to me. I'll try the styrofoam thing tonight when I get home. As well as testing the temperature in some ice water

The anti-short cycle delay sets a minimum off time. I like to set it to the max 12 minutes. Nothing much can happen to the beer in a 12 minute time span and it maximizes the protection for the compressor. Keep in mind that the air in the freezer will continue to cool even after the compressor shuts off. This is completely normal and nothing to worry about. Be sure to allow sufficient time for the system to stabilize when changing the set point or differential settings.