"IMM" wrote in message
...
SNIP
Having 80C water through UFH pipes is ridiculous. It makes the floor far
too, hot. Then there is expansion contraction, etc. The Danfoss system
is
assuming that the supply water is less than 55C.

SNIP

IMM.
Read the link http://tinyurl.com/4blyr.

"Maximum flow temperature 90°C "

" Used in systems which are predominately heated by radiators (normal system
design temperatures 82/71°C) and where Underfloor Heating represents only a
minor part of the system, for example a single room or small extension "

The water will not flow through the pipes at 82/71 because the water is only
let out of the system after it has given up some of it's heat, so it is only
topping up.

Baz