Just plugged a brand new chest freezer into a brand new Johnson analog set at 34 degrees (lagering). The chest freezer power lights lit up and I thought everything was fine. Checked the next day and the lights were off. The power lights popped on here and there after unplugging/plugging back in and fiddling with the freezer's control knob. When I plug the freezer directly into the outlet, it works totally fine.

Is my Johnson control busted? Or does the freezer only kick in when the temperature raises above the Johnson's setting of 34?

Seems weird to me. Thoughts?

2 Answers 2


Read the configurations instructions. Commonly over looked things are.

  • Mistakenly set to heating, not cooling
  • Large temp variant. Should be set to 1-2 degrees
  • Fahrenheit / Celsius toggle.
  • Set freezer to coldest setting
  • Temp prob placement. Best to be in a thermowell in the wort. Alternatively tapped to the middle section of the fermentor. The metal part of the prob shouldn't be touching the fridge wall, if going for an ambient temp.

Edit: Didn't catch it was a analog controller. Only the prob placement and freezer setting applies. The controller works by cutting all power to freezer once it is at or below the set temp. Lights off on the freezer is normal unless currently cooling.

  • What he said ;-). I'd like to add that, after having used both, I'm absolutely sold on the digital version. Also, in case you didn't know: the temperature probe is NOT submersible. The cable (the capillary tube, whatever) is clad with some presumably waterproof plastic, but the joint is not sealed.
    – Glasseyed
    Commented Mar 7, 2016 at 0:58
  • @Glasseyed indeed, that's why I said to use a thermowell. Pretty sure it's not an option on the analog though. Its all copper with a large bulb. Just won't fit. Commented Mar 7, 2016 at 15:06
  • @ Evil Zymurgist: Yes, I noticed 'thermowell' in your post, but figured some forum members might not know what a thermowell is and why it's essential. If you're not immersing the sensor in anything, it's still essential to keep it away from the freezer/kegerator cooling coils. As for sensor size, the 2 analog controllers I owned (before giving one away and tossing the other) had the same style of sensor as the 2 digital controllers I have now. Cheers!
    – Glasseyed
    Commented Mar 7, 2016 at 20:57

The freezer will not run constantly. It will cycle on when the temp rises above the set temp and more cooling is called for.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.