Robert Gammon misunderstands again:

Power-Pipe now has a US web site that gets them around the customs issue.

That's irrelevant.

The pump with differential temperature control is the secret to higher
recovery rates. Flow rate thru the coil in excess of flow rate of
greywater will more efficiently transfer heat to the potable water.

That's quite different from what I have in mind.

How do you manage to be so wrong so often? :-)

Nick