Temperature Limited to 1.000 e+000 in a zone of do
 

I am trying to simulate a heat source in a domain. For this purpose I've created a solid (box) Volume with the properties of wood. The strength of the source is 45 W (constant). However, during each iteration a message is flashed - " Temperature limited to 1.000 e+000 in 144 cells on Zone 2 in domain 1." Then I changed the geometry of the heat source zone to cylinderical, and made a denser mesh . The message during iterations was as follows: " Turbulent Viscosity limited to 5000 in 4898 cells in zone 2 domain 1. "

What can I do about these omenous messages ???? The simulation is rendered unsuccessful.

Thanx and Regards.