One major consideration when
installing a floor heating circuit in an
existing hydronic system is the need
to control water temperature. Most
hydronic systems in the U.S. operate
at water temperatures necessary for
common fin-tube baseboard convectors
— usually in the range of 160° to
200°F. In a radiant floor, however,
temperatures this high will overheat
the slab and possibly cause cracking.
Providing lower-temperature water to
the floor heating zone, however, may
cause flue-gas condensation at the
existing boiler.
Large-scale floor-heating projects
use motor-operated four-way mixing
valves and electronic controls costing
as much as $1,000. But small projects,
such as one-room additions or bathroom
remodels, don't have room in
the budget for this kind of equipment.
Here are two piping strategies
for adding