Here's a pic of my Love TSS2 with 10' stainless steel tip probe. The outlets on the 2 relays are fused to protect the controller. The switches are a fancy way of unplugging the chest freezer or 40W aquarium heating pad to prevent cycling them if not wanted without changing an internal parameter or to prevent a mistake from a bad parameter setting.
I have a Johnson A419 and have trended data showing that 3F temperature variations is the tightest control possible with the controller probe insulated-over on the outside of the fermenter.
I've trended data with the TSS2 and it can match the A419 control response and also improve control to about 1.2F temperature variations with the controller probe insulated-over on the outside of the carboy. The TSS2 has a lot better program options and seeing the decimal point temperature read-out on the display is really handy.
I've learned that when my freezer turns off after a cycle, the fermenter temperature drops another 1F no matter how big the differential is set. I've found it best to set the cooling differential to 0.5F to keep tight control (freezer cycles about every 1-2 hours) and increase it to 2F-3F when temperature fluctuations don't matter (freezer gets cycled about every 4-10 hours).
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