Immersion chiller questions

I am setting up my all grain system and was given 2- 25ft copper (3/8) immersion chillers. One I have set up as a pre-chiller in an ice bath and the other in the wort. It took 45min. to cool 6 gallons wort to just under 80 (in a keggle with the coils submerged). Is there anything I can do to decrease that time? I didn't stir the wort while cooling and will try that next time.
Thanks

Stirring the wort tends to make a big difference. I run my tap water through a chiller plate inside a jockey box (filled with ice) and then a 25 ft Immersion chiller in the wort. Two weekends ago it was upper 80's in my garage and I cooled the entire batch in exactly ten minutes. It was the first time I used that set-up and dropped the time it took me to chill the wort by 75%.

I bet stirring the wort would cut the time by at least 10 minutes - if not 20 minutes.

Definitely stir. Once the output cools down, stir it a few times and you will see how hot the output gets again.

Thanks. I didn't think about stirring last time, but will give it a go next week.

Stirring or just moving your coil up and down is important. What temperature is your groundwater? How fast are you running water through the coils? Did you look to see if maybe the ice in the pre chiller "bridged" around the coil.

I have 2 chillers as well and I was able to get mine from just short of a full rolling boil to pitching temps in about 20 mins. I have a submersible fish tank pump that maxes out at 291gph (according to the label on the pump). I put that into my kitchen sink and filled it with ice and just a little water to get the pump started. Off the pump, I have 1/2" silicone tubing that goes to my first immersion chiller (3/8", 25ft, stainless steel) that's sitting in my brew kettle. From there, the water goes through 3/8" silicone tubing to my second chiller (3/8", 25ft, stainless steel) that's sitting in my bottling bucket that's also filled with ice. Off the 2nd chiller, it goes through 3/8" silicone tubing and empties back into the kitchen sink where the pump picks up the water and cycles it through all over again.

When I turned the pump on initially, I watched the temp drop right in front of my eyes from 210* (give or take) down to 190*, almost instantaneously. From there, it was a relatively steady decline until it leveled out right at 100 degrees at 15mins. By then, all my ice had melted since I wasn't as prepared as I thought I was. My tap water was only getting as cold as 65* and the water coming out of the 2nd chiller was still holding right at 95*-100*. I kept the pump running with cold tap water and after the final 5mins, I was able to pitch at 85*.

Next time I'm going to try using my 2nd chiller as a pre-chiller rather than a post-chiller just to see if it makes a difference. I'm trying to stay away from salting the water because I don't want my pump to ingest the salt and tear it up. Maybe I can salt the water that the chiller is in (either pre- or post- ) and next time I'll have more ice and hopefully I can get it down to pitching temps right at 15mins.

Thanks for the advice. I used an ice water prechiller and stirred most of the time and got it from boil to 75 in 12.5 minutes. That will work for me.

Stir stir stir.
Or, do what a friend of mine does. Get a march pump, and use that to recirculate the wort (out from the drain valve, back up into the pot). It makes a huge difference in the cooling time. For big batches, it helps a lot.

Update: this time I put 1 chiller in a bucket of ice and just enough water to let the chiller sink all the way. The 2nd chiller was in my kettle and it emptied into the kitchen sink where my aquarium pump picked it back up. The sink was also full of ice. I turned the pump on and within about 4-5mins, the ice in the sink was almost completely melted. So I drained a majority of the water and dumped more ice in on top of the pump. By about 8 1/2 minutes I was at 90 and by 10 I was pitching at 85. I bet some salt in the prechiller bucket would keep it even colder and I may be able to get it down even faster.... 7 minutes may be in my grasp. I'll give it a shot next time. It blew my mind how fast it cooled!!

even with a prechiller, 25' is going to take a long time to cool a keggle.
Its not the wort, its that big piece of stainless holding heat.