Chest Freezer Fermentation Question

[brewzofo1]

I bought a small chest freezer on Craigslist several months ago. Only paid $25 and it's a Wood's brand. It works fine. I plugged it in and it got cold very quick. Not sure on the size, but I can fit only 1 carboy at a time. I recently bought a Johnson A419 temp controller for the freezer and am planning on using to control my fermentation. The A419 works fine. but when I set the SP setting at 68 or 70 nothing seems to be happening with my freezer. The freezer still works fine when I plug it in by it self. It seems like the inside temp of the freezer is whatever the outside temp is. It is located in my garage and the temp has been around 64-66F. The freezer does kick on but when I set the 419 at 68 or higher it just sits around 64-66. Even when I bump up the SP to 83-86F it's still around 64 inside the freezer. Am I doing something wrong? Thanks.

 

[alien]

I guess the only heating you have in there is the ferment itself and it's not enough to raise the ambient temperature inside the freezer more than a few degrees.

 

[TCGoose]

If you have the controller overriding the chest freezer thermostat, it will only provide cooling. Since the temperature within the freezer is lower than your set point of 68, the compressor will not run. You will need to add a heat source in order to raise the temperature to 68.

If you just want to test whether the controller is working, make the set point 55-60F. The freezer should cycle to cool to that temperature.

 

[brewzofo1]

Okay. So I need to get a heat source to put inside my freezer. A lamp with light bulb? How bout a regular type heating pad (like for your back/neck/leg/etc.)? Then I need to plug the heat source (heating pad) into an outlet and place it inside the chest freezer? Tape the temp probe to the carboy. Plug the freezer to the Johnson A419? When it temp of the wort inside the carboy reaches 68 or whatever the setting is at A419 will turn on or off the freezer? Am I understanding this right? Thanks again.

 

[TCGoose]

Either would work, but you would be simultaneously heating and cooling at the same time once you reach 68F, which is a waste of energy. 64-66F is a pretty ideal range for ale fermentation.

 

[Rbeckett]

Might also want to consider putting a small fan inside the freezer to circulate the air and facilitate heat exchange from the carboy to the surrounding air. Radiant heat transfer will cause peaks and valleys that will vary your wort temp considerably. I use an Ebay STC 1000 and a seed starter mat and it cycles perfectly within two degrees of my set points consistently. So I have a variance of no more than 4 degrees total from warnest to coolest. Hope this helps, I am not familiar enough with the A418 to be of any use programming it to work any better. An STC-1000 is easy to build and very easy to operate too. Enjoy and dont get discouraged, some one will know the exact solution eventually.
Wheelchair Bob

 

[grainbill]

Put the probe in a jar or bottle of water so you are "reading" the temp of the liquid instead of the air temp. Just remember to unplug the freezer and plug in the heat source...