Hello,
I am simulating a cooling coil, Type 508a, in TRNsys. I supply air through a fan, and fluid through a pump, and control both of them with the condition that they run only when the air temperature is higher than the fluid temperature (as in the attached photo).
The problem is that when I run the simulation I still get heat transfer output from the cooling coil even when the fan and pump are not running, and in some periods even when the air temperature is lower than the fluid temperature. I have tried to fix this problem but with no results.
Please, do you have any suggestions for this? 
Enxhi Daci
R&D Engineer, HVAC
Gether AS