On Tue, 15 May 2007 17:37:01 GMT, Lobster
wrote:

Actually, I don't want to position it anywhere near a window; I want
it to go straight out through a cavity brick wall, to appear about 8
ft above the public pavement outside. Is this acceptable?

Sounds fine in principle to me, but there might be other issues (eg
proximity to a boundary). And where does your pressure relief drain go?
That might be an issue 8' above the pavement!

Thanks for the tips. Good point about the pressure relief drain. I
could route that into a nearby bathroom sink waste pipe. Would that
breach any building regs or otherwise pose any problems?

Duke