The message ews.net
from "Doctor Drivel" contains these words:

Better having it connected to a drain od course. But if one is difficult to
get to the Atmos is ideal.

And expensive! I'm going to have to do a good deal of thinking before I
choose a boiler, but it looks like a stainless heat exchanger is going
to be right up there high on the list.

--
Skipweasel
Pay no attention to the man behind the curtain.