I finished the heat exchange piping this morning. This is how the heat exchanger works. Notice the hot in the upper corner going IN and the warm after exchanging its heat going OUT in the lower corner. Conversely the cold is going IN at the lower corner of the other side and the warm is going OUT. In other words the temp exchange is piped opposite of one another.
This is my piping before I hooked up the chiller.
On the left upper side hot is being pumped into the heat exchanger and so it will be leaving its heat in the exchanger and returning to the storage tank much cooler on the right hand side. Conversely, the cool water from the radiant pipes is entering on the right lower side, it will heat up and is being pumped back into the radiant system on the lower left–to the boiler in this case.
Cooling works in a similar fashion. The chilled water leaves the upper outlet on the chiller and enters the upper left corner of the heat exchanger. But it also flows to the input of the chiller at the tee just before the exchanger. This is where the system can be turned off for the winter. Then it gives up its chill to the water in the radiant system and leaves at the upper right corner of the system and back to both the output of the chiller and the input of the tank. The radiant system water enters again at the lower right side of the heat exchanger and leaves to chill the floors at the lower left. Either the cooling or the fireplace heater can be closed off from the heat exchanger system with ball valves depending on the season.
I switched the wiring on the pump outlet to allow the pump to run continuously and plugged in the chiller controller with the temperature sensor and power connected from the chiller. With the pump running and the water running through just the top of the heat exchanger the chiller compressor kicked on and ran for about 10 minutes as the temperature on the controller dropped from 64.9 to 55.5. For some reason the controller continued to drop the temperature reading until it reached about 44.2! Then it started to go back up. I ended up unplugging it when we left the house for a few hours. But at least I know it works. (Rather I was tricked into thinking it was working–but it was not cooling the water as much as the internal sensor indicated at least that is what the new external sensor showed.)
The trick will be to get the valves to open and the circulation pump to start on a call for cooling instead of a call for heat. (Not a problem with the correct re-wire of the thermostats.) That should involve the valve from the heat exchanger to the radiant system which I may just leave open, and the valves to the floor piping which need to have the thermostats rewired for the cooling function. Plus changing the pump wiring around again and hoping it all works.