The pre-chiller is recommended for areas with warm tap water, or to simply increase the efficiency of a wort chiller. If your tap water is 80 F (27 C), you will never be able to use it to chill a wort to 75 F (24 C). The solution: a pre-chiller placed in a five-gallon bucket with a bag of ice to dramatically reduce the water temperature before the water runs through the wort chiller. This will increase the efficiency of the wort chiller.
The pre-chiller is an addition to a wort chiller, not a substitute. A wort chiller is still required. The pre-chiller comes with a female garden hose fitting on the inlet side and a male garden hose fitting on the discharge side that fits the inlet side of most wort chillers and plate heat exchangers such as the Therminator™. Add the kitchen sink adapter to hook up the pre-chiller to a kitchen sink faucet.
An ice saving tip: If using the pre-chiller with an immersion chiller, run the chiller for 5 minutes to bring the wort temperature down before putting the bag of ice into the bucket with the pre-chiller.