Here is a short list of things to check:
- Is temp probe from FTSs controller properly inserted/seated into thermowell?
- Is your neoprene jacket on?
- Have you confirmed the temp of chill water source? It should be in the 30's or 40's at most and always 10-15F lower than your target beer temp for best results. The bigger the delta between your chill source and target temp the better!
- Given enough time, you should be able to settle out (if you are really pushing the system like with glycol or a large volume of dedicated chill water and not just ice in a box type deal) you should be able to get to within 3-6F of source water temp (there are too many variables for us to give a more exact number - but 3-6F is a reasonable range in most setups.
- Do you have a FULL BATCH in the fermenter? If you are doing a partial, then the coils will only partially engage and you won’t get good efficiency .. Lagers will be a problem!
- Are your lines (in/out chill fluid) insulated? If you are using just the vinyl tubing included with the kit and no insulation, you will have thermal loss. If very low temps are critical to your process/application - then you'll need to tweak your lines for more insulation.
- Did you put some insulation on top of the lid?