I’m gonna have to go look at some we have. We don’t have three way valves like yours or pumps. The pool pump makes water flow through the heater. Butterfly valve in the 6” line is partially closed between two 6 x 2 1/2 tees. That forces water through the pool heater as I recall. The water isn’t real hot coming out of the heater, guess that’s why it’s all cpvc. I cant remember which brands we use. I’m off all week but I’m gonna check Monday. I’m curious now. I’ll take some pics of the set up we have.
