I just finished installing...everything. Anyways, I'm using my sidearm heat exchanger on an electric water heater (still on). I took the drain off of the water heater and hooked up the sidearm domestic side down there. It feeds back in at the hot outlet. While showering, I get hot water right off, then it cools off throughout the shower. It never did that before. I suspect I need to switch the sidearm to feed back into the cold water inlet instead of the hot water outlet. I'm thinking that the hot water draw off of the tank is sucking some water off of the top of the tank, as it should, and some water through the sidearm as well. Since the sidearm isn't capable of heating domestic water to shower temps on demand, my shower cools off. Is my thinking correct?