On Wed, 4 Nov 2015 21:35:01 +0000, rick wrote:

Can't do that ... max temp I can have store get to is 60 degree
any higher and you risk damage to underfloor heating pipes.

They should have a mixing valve to prevent the floors getting too
hot.

No the design has a mixing valve on the DHW take off, but the main feeds
off for the UFH loop is not via a mixing valve ... the main tank stat
prevents it going over 60 degree.

Strikes me as bad design then. Can't you fit a mixing valve between
the flow and return of the floor loop such that the pump circulates
via the valve when the temp approaches 60 C.

--
Cheers
Dave.