In article ,
Robert Gammon wrote:

Nick's will have to be connected ONLY to non-toilet drains. Nick's will
have to be periodically cleaned of matter that goes down kitchen sinks
and out the clothes washer drain.

Connecting a GFX to a toilet drain is not going to be very sensible,
however, unless you heat your toilet water - makes the most sense when
connected to drains that might have hot water - putting it in the
blackwater stack just adds one more way to have a toilet flush make your
shower uncomfortable, and reduces the potential efficiency by reducing
the temperature differential across the heat exchanger.

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Cats, coffee, chocolate...vices to live by