This document may contain valuable information proprietary to CleanTech Analytics which is private and confidential. It may not be shared, copied, stored or transmitted in any form without the prior written consent of CleanTech Analytics
Found the problem.
1) used FiniteDifferenceMethod and got convergence of a very thick heated floor slab -- effect on problem...small
2) Found that the Load Averaging Window was set to 12 for a 60 TimeStep simulation. Reset to 1 -- effect on problem...large
This is a lesson I will not soon forget.
Note: It seems FDM may be a good way of tackling thick constructions, but be aware that it takes ages longer to simulate.