As Frank asked...
Specifically which VersaCamm SP-540?
And a couple of questions.
Are both sets of heads old heads?
Do you get anything at all when you do a test print or is it completely blank?
When you do a medium or power clean, do you see ink coming through the system? You can check this by cleaning the waste bottle completely, do a medium or preferably a power clean and see if there is any ink in the bottle after the cleaning is done.
Did you "initialize the limit" to make sure the heads are aligned to the caps, giving you a good seal?
Do you have a meter to do some resistance measurements?
Based on the answers to these questions, I can try to help you.