Questions on Radiant Heat
With Water Heaters
To the Editor:
Good article on using water heaters
for radiant heating ("Using Water
Heaters for Radiant Heat," 11/98). It
answered several questions I've been
asking myself for awhile. I still have
one question: What's the function of
the expansion tank? Certainly there
will be changes in the volume of the
system as hot water warms up various
parts of it, but the same applies to any
plumbing system. I've always assumed
the difference was made up by flow
back into or out of the supply mains.
Bob Fankhauser
Portland, Ore.
Bill Clinton responds: Traditionally,
plumbers have indeed relied on volume
increases flowing back into the mains
and have not installed expansion tanks
on water