Need Help - Fermenter not controlling

[kevinb]

I finished my fermenter with a 5.0 Cu ft freezer, tc9102 controller, and a My Heat Personal Ceramic Heater. I can't get the temp to control. I am just testing it out. The temp probe is in the air. Not only is it not controlling, there is a big different between the temp reported by the controller vs. my secondary thermometer.

I would appreciate any advice. If anyone else is using this model, can you please tell me what you are using for settings for differential and the cycle time settings?

 

[flars]

Try putting you probe in a bucket of water. Start out with the water in the bucket the same temperaturre as the wort.

 

[ryan_george]

First off, please check your spelling and grammar. It can make a big difference in what you're actually asking

Where is this "secondary thermometer"?

I assume the main issue is that your main temp probe is sensing the temperature of the air in your chamber; which isn't necessarily a big thing, except for the fact that air cools/heats much quicker than liquid/wort. Your chamber is shutting down before the large mass of wort has had a chance to react to the relatively small mass of air around it. You need to dampen the response of that temp probe by putting it in to some vessel filled with liquid, or (ideally) the wort itself.

If you can't measure the temperature of the wort directly, you can set the temperature of the controller a few degrees lower (or higher) than your desired temperature to account for the lag. It won't be perfect, but it should help.

 

[kevinb]

Ryan_george

You are right, I typed that quick and did not proof read.

I think part of the problem is that the ceramic heater is too big. It runs for a minute and overshoots so the freezer kicks on which then over cools. The system ends up oscillating back and forth. I bought a reptile heater that a saw in another thread that is a much lower wattage than the ceramic heater. I am also going to put a temp probe right on the side of the carboy as suggested to see what the wort temp actually is (is this case test water. I can't imagine what beer would taste like at this point). Wish me luck.