When querying the bugz database, strings are case sensitive. So, entering "pump" or "Pump" in the Summary field, does not provide the same response for the search. First time I used the querying system, I missed some important information about "pump" becoz somebody entered it with a capital letter at the beggining.
This is currently a limitation of the database. We are working on a solution for this problem.
This functionality should be there now with the new Bugzilla on the query page. Please reopen if not the case.