Temp Controller is way off...

[DarkUncle]

I have one of these:

http://www.amazon.com/Johnson-Controls-A19AAT-2C-Temperature-Controller/dp/B0002EAL58

I dropped a thermometer in my chest to monitor the temps inside and I'm noticing that to keep the ambient air inside the chest freezer around 66-67 degrees I have to turn the temp controller down to like 50-55 so it seems this controller is not very accurate. Also, the temps can rise 5-10 degrees before that thing switches my chest freezer back on.

I need something more accurate and I would also like to employ a heater strap or pad of some kind during the cold months as my freezer is sitting in the garage which can see temps down to 50 degrees or so in the dead of winter.

What's my best setup to regulate my temps in this chest freezer? Are the digital temp controllers more accurate? Something like the Uni-Stat II? A bit more expensive I know but I need more accuracy.

Thanks,
Chris

 

[gandelf]

For a mechanical controller it is the nature of the beast. A PID or digital controller can be accurate
to +/- one degree. A PID and RTD is economical and very accurate for controlling temps.

 

[Dolomieu]

Where is the probe located?

Though a pid is more accurate I have a hard time believing that they would work with a freezer, with out short cycling and killing the compressor.

I tape my probe to my fermenter with insulation holding it against it.

 

[DarkUncle]

I keep my probe in the air inside the freezer as I typically have more than 1 batch fermenting at any given time. But the temp controller I'm using typically allows for temp swings approaching 8-10 degrees. That seems to be a bit much. I know the fermenting wort is typically higher than the ambient temp so I try to keep that ambient temp about 5 degrees lower. So if I want the temp in the freezer to be 67 I dial back the temp controller to 62 to account for the warmer wort. However, my thermometer typically reads 68-69 before the freezer switches back on even though it's set at 62.

If there is a better way I should be doing this please do make some suggestions.

Thanks

 

[Indian_villager]

Keep the probe in a 1/2 gal growler. If all else fails pick up an STC-1000

 

[Dolomieu]

So with one probe/one controller and two fermenters you are kind of limited. Maybe not limited but you have to make choices. One way is to take another container like a 2 liter bottle and put the probe in it with water. then position in between and in contact with both your fermenters.

Or if you are just conditioning one fermenter and actively fermenting in another, attach the probe to the active fermenter.

IF you want to continue just dealing with ambient temp you need to at least get a fan in there. It will help homogenize the ambient air, though getting the probe next to, or in your beer is the better option.