I have a CPP-2, and here's how I use it in hot weather.
1. Fill the tub.
2. Fill a clean bucket with cold water, and drop some ice packs into it. Using some tubing, hook an aquarium pump up to the Jobo cold water inlet, and put the pump in the ice water.
3. Set the temperature and develop as normal.
The Jobo will add cold water as the water temperature in the tub rises. Be sure to hook some hose to the Jobo's overflow spigot, unless you have the Jobo in a sink.