Symptom: pump does not turn on

A new PhD Ultra or Pump 11 Elite pump does not turn on.

To resolve the issue:

Please slide the 'Power Source' slider switch (which is located on the back of the pump, next to the power plug, see photo) down to 'RS-485' and then back up to 'DC in'  (or ‘AC-in, for PhD Ultra). If that does not solve the problem, please contact technical support.