Wondering out loud if I could accomplish a few objectives by deploying an Alpha pump pumping INTO the mix side of a typical Honeywell or simmilar mix valve. In my system my goal would be to minimize return volume and thus mixing into the bottom of my storage tank ( maximize stratification ). See my sketch. Would the mix valve set at say 120* cause a downstream head condition that the Alpha would 'see' as a varying number of zone valves? If there was little heat demand in my house the 180* supply water would come back to the shop at say 170*, the mix valve would clamp down on the hot side, and the Alpha would trim back to low flow. If the sidearm water heater, furnace fan ( coil in plenum ) and in-floor system were running in the house the return water cools below 120*, mix valve opens up, Alpha spools up, and it should stabilize at 120* ? I know the sensor on a mix valve is on the mix port, but will it modulate correctly with 'backwards' flow ??? Also, since my in-floor system in the shop has to mix down to a low temp, instead of returning that 120* house water to the bottom of the tank, I'd like to route it as supply to the shop manifold. If the system were in perfect balance it could conceivably return only 85* water to the bottom of the storage tank. Somehow I know I'm missing a thing or two in this sketch to allow both the shop system and the house system to operate independantly without some weird repurcussions. If you see it, please chime in, as I've never seen a sketch like this before. There probably is a reason...... One issue is the shop floor system has to pull it's full supply thru the house loop. I wondered if it would be 'starved' if the Alpha was clamped down - but even if it were at a meek 2gpm, with dT = 120*-85* = 35*, it would equate to 35,000BTU. I'd suspect if I needed more than that in my shop floor, that my house would also have a heat call somewhere.