Does the heroic code expressed in Beowulf conflict with a Christian sensibility?

That is a difficult one, because Christian believes and Beowulf are a matter of interpretation. What one may view as sensibility is actually just a matter of common sense. However, every aspect of life is covered in the Bible and thus to suggest (if this is what you are suggesting) Beowulf is explained taking Christian values into consideration? No. Things were different at that time and thus the perceived sensibility to Christian belief.