So I gave up on the controller and installed an aquastat on the buffer tank with a relay for the pump to the air handler/exchanger, seems to be running now. I see lots of discussion on heat temps but what should I set for a cool temp and differential? Currently I have it set to 40F with 4 - 10 degrees differential depending on the weather, is that too low? The system is an Econar 4 ton W2W system.