Odd Fermentation Control - Good Beer Temp

[tofuguy]

Hi all, so I have been using my Brewpi fermentation chamber for almost a year now with little to no issues. I am not going to say this is an issue, but rather an odd notable.

So I brewed a APA (1.053 OG) and cooled to 70F and pitched one packet of US-05. Everything started off normal, but as you look at the attached picture, around 1.5 days later the Brewpi started to walk up the chamber temperature to hold a 67F beer temperature. (I have an upper limit of 85F set for protection.) I have a liquid crystal temperature strip on my glass carboy, and it reads between 66F and 68F, so the beer temperature probe is not out to lunch, and when I open the chamber, its definitely near 80F. I felt my cold plate in the fridge to see if the the cooling relay was welded, but its not cold.

My question is, has anyone else experienced this with a fermentation?(Brewpi or not) Where the chamber had to heat quite a bit higher than the beer during a time period where you expect active fermentation and the chamber to be at a temperature lower than the beer temperature to counteract the fermentation heat.

 

[tofuguy]

So, update...

I went down to my chamber, opened the door to feel the carboy and move the chamber temperature probe about 2 inches (where you see the sudden drop in chamber temperature from 85F). Now the chamber temperature seems to be at a more appropriate level. Very odd, I cannot explain this.