About losses and tank temperature in SWH model

Hello,
I am runnig a simulation using solar water heating model. I have a problem with the results of tank temperature and the losses to environment, the graphs are showing a very negative values that don't make sense. I would like to know where I could have the probem so that the values of tank temperature and losses are negative. (The cold water temperature have the same profile).
Best Regards.   

Hi Marwa,

Please attach a copy of the .sam file that demonstrates these results.

Best regards,
Paul.

Dear Paul,
Thank you for your reply. Please find in the attached file a copy of sam file.
Best regards.