We have a 20" x 48" Intex Ultra Frame. We've been running a 1500 pump on it for the past 3 years and decided to purchase a 2500. We bought the 633 and hooked it up. The water fills into it, you can hear the motor running, but no water is being sucked in or pushed out the hoses. Any ideas? We watched the video, we checked for air lock, etc..... We aren't very mechanical folks either. Any ideas would be appreciated. Thanks in advance. We did hook the old pump up and it still works so we know the hoses are fine.