Cause: Your Shell Thunder's fan might have gotten stuck to the side during shipping.
Is there a solution?: Yes!
Here's what to do (takes about 7 seconds): With your Thunder open, plug it into a power source, then gently nudge the fan to help it begin spinning. It should then spin for 5 seconds, and stop until the enclosure gets hot enough to engage the fan again (when it reaches 35 Celsius).