dwhr

Currently have 4" cast iron stack, from WC, it's connected to an elbow, followed by two 4x4x2 wyes that connects the kitchen sink and the bath/lav, another elbow and goes vertical into the 4" abs stub that goes into the bench footing (main horizontal drain that goes to municipality's sewer)...

I've purchased a 42"x4" power-pipe drain water heat recovery system ($450 online!) and I'm trying to decide the best way to plumb it into the supply for our system. We are on well water which, according to the pressure indicators on our filters, maintains 40-55psi on a 1" copper line. The...