[TRNSYS-users] HELP: Error creating the wall transfer coefficients

[Marshall L Sweet/sweetml/O/VCU <sweetml@vcu.edu>]

TRNSYS Users,

I am using TRNBuild to create a type 56 building model.  When I save the building I get the following error message:

Error creating the wall transfer coefficients:
Unable to find a root after indication that a root exists.
Maybe the timebase is too small.
Please check the INF file for further information.

Upon checking the INF file the error is occurring at the end of the file reading:

UNABLE TO FIND A ROOT AFTER INDICATION THAT A ROOT EXISTED
 
 CHECK THE WALL TYPE AFTER THE LAST CALCULATED WALL
 OFTEN THE WALL CAPACITY IS TO SMALL TO CALCULATE A TRANSFER FUNCTION !
 
 CHECK ALSO YOUR TIMEBASE !

The wall type after the last calculated wall is a ceiling consisting of two layers (wall_board and R-13 insulation).  I have used this exact same wall type in other models and it has worked fine.  The coefficients (A, B, C, and D) of the transfer function for this specific wall type are identical in both models.  The timebase is also the same.  The capacity is different but I have increased the capacity and I am still getting the same error.

What is going on here?  Where exactly is the capacity?  What is meant by "unable to find a root after indication that a root existed?"

Thanks in advance,

Marshall