I’m having trouble controlling my Johnson, a419…couldn’t help it. I’m using it with a mini frig the kind with the ice maker cooling shelf. The readings seem to be all over the place and do not match the thermometer I hung inside. I have the probe dangling in the center. Its cooling way below what my set point is. I have differential set at 3 and auto cycle at 1. It could be the nature of how the mini frig cools but I’m just wondering if there is something with the setting I could do to make it work better.
Try attaching it to a carboy/pail with just water. If you have a temp strip on the fermenter , after 12hr or so you should see a steady temp.
Opening the door with the temp prob free in the air can make things wacky.
Whether I tape my temp probe to the side of the fermenter, put it in a glass or bottle of water, or hang it in free space, I find that I need to set my controller about 2 to 3 degrees above my desired temp. I like to keep the actual fermenter at around 64. When I set my controller to 66 or 67 and leave it alone, quit chasing temps, and let it settle down, the crystal temp strip on the fermenter locks in at about 64 and stays. I then just let the setup do its thing.
My biggest fault in the beginning was chasing temps. When I set it and forget it, “so to speak”, everything settled down.
Hope that helps.
Thanks seems like a very logical approach