Freezer to fridge conversion, where to put temp probe?

[rikun]

Hi there,

This is not a keezer (at least for now), but I think this forum is the best source of information for these conversions.

I converted a deep freezer into fridge with the STC-1000+, and test ran it yesterday. I inserted my temp probe into the original place after I pulled the original probe out. My intention is to run it around 32 F and store large quantities of meat in there. And when I don't need it for that, it's time for some brewing ;-)

It runs fine, but it runs pretty frequent and I have a hard time keeping it stable. It is pretty empty, but I tried to add some thermal mass with 3 x gallon bottles of cold water in there.

My set point is 32 F, but after the compressor stops it gets a lot colder, down to 25 F. And vice versa, it gets a lot warmer than my set point + hysteresis is set to. In other words, there is pretty long delay for the cooling to start/stop after the compressor kicks in/out. My cooling delay is set to 5 minutes currently and the compressor almost cycles that frequently.

Would placing the temp probe into small glass of water help? I wouldn't want it to run too cold for too long, so the meat doesn't start to freeze on the outside. Generally meat starts to freeze around 29 F.

Is it a good practice to try to emulate "meat temperature" by the water, or just try to stabilise the air temperature around 32 F? I shouldn't have the need to add anything warm in there, just meat that has been transported in ice to my place.

I was thinking of raising my set point to around 35 F and setting my hysteresis to zero to try to counter the extended cooling after getting down to the set point...

Or should I just fill it with thermal mass and give it few days to stabilise?

 

[owmatooth]

thermal mass will help stabilize things the best, but I also would place the probe in a container of water to keep the cycling down. The bigger the bucket the more stable the temp. I use a 2 qt mason jar. Air temperature is too variable to try to keep within a few degrees.

 

[rikun]

Thanks. If I have lots of water where my probe is, should I adjust my hysteresis pretty tight around my setpoint?

Maybe just a glass of water?

My thinking is that, if I have big hysteresis with large thermal mass with the probe, my air temp is going to swing wildly just to keep the big mass stable.

Normally I wouldn't mind that, but I don't want my air temp to drop too low so that my meat doesn't start to freeze on the outside...

 

[owmatooth]

why would the big mass be less than stable? it'll be more set than the glass of water would be. How long are you storing the meat, and why aren't you freezing it?