The heat exchanger where it attaches to the pipe that used to go over the ceiling from the boiler directly to the basement slab. Now I cut it off with that blue-handled ball valve, grab it in that near-horizontal pipe, send it through the heat exchanger primary (where it emerges from that diagonal pipe to go down to the boiler again), indirectly heating water in the secondary which goes upward to the slab in that pipe in the top right corner.

The other end of the heat exchanger, with the new expansion tank and pressure release valve. You can also see the top left corner of the circuit breaker box and the top of the solar sufficiency controller in this photo.

The new pressurized antifreeze supply. At the bottom is the unpressurized antifreeze reservoir with the drillpump used to pressurize it. In the middle is the hydronic expansion tank that I use as a pressure tank. On top are the pressure relief valve, gauge, check valve, and taps for that attachment of hoses. The small plywood board serves as a step allowing me to get up to the large shelf (unseen to the right) which lies beneath my solar plumbing. That black boxy thing is a pressure-activated switch normally used in well pump applications. The blue box on the right side of the photo is its analog in our well pump system.

A close look at the pressurized antifreeze supply.