Just fwiw: the solar boilers generate 6mb/t steam when they're operating at peak efficiency, and the macerator consumes 4 mb/t.
Two things can govern the efficiency of the boilers: 1) their heat, 2) how long they've been active (they begin to lose efficiency over time)
Make sure you point the solar boiler into the pipe. That's not a vent; you're venting steam. If memory serves, if you have a pipe on the back of your boiler, you want to stand in front of it and wrench the corner to reverse it and point it into the pipe.
Ah! Am at work but will check tonight. Also I think my macerator is right on the chunk boundary meaning the pipe connects accross the chunk to the machine. I don't think that would be a problem though if both chunks are loaded ie I am in one of them?