[Oscar]

Update:

I reinstalled the pump even with the broken impeller and it surprisingly works and is generating bubbles and full flow.

There were 2 steps to get the pump primed:

1. As Lee9 suggested put my finger on the end of the intake valve for 10-15 seconds to allow the pump to build up a bit of pressure.

2. Do not open the air valve to 100%. Turn it until you hit the "SWEET SPOT" where the pump becomes almost silent. That trick was posted on the DD website although it does not appear in the manual.

Thanks all for the prompt feedback.