Clear out debris from the system. Check the skimmer and Whisper Flo pump basket to see if there is a build up of leaves and dirt. Too much dirt in these two areas will make it more difficult for the pump to suction the water from the pool into the filtration system.
Unclog the impeller. The Whisper Flo's impeller is located behind the pool pump basket after the diffuser assembly. To access the impeller, turn off the filter, open the Whisper Flow pump basket lid, remove the basket and reach down the tube leading to the impeller. Remove any debris or leaves you find there. Also, touch the impeller to see if it wobbles back and forth. If the impeller is wobbly, it needs to be adjusted. A wobbly impeller cannot create or sustain the necessary vacuum it takes to maintain a clean pool. Take the Whisper Flo pump to a technician to have the impeller adjusted.
Check the pool return water flow. If the water flow is weak after cleaning the debris from the skimmer basket and the pump basket then that means that either the filter is dirty, there is a vacuum leak or the pump motor assembly is in need of service.
Read the filter housing pressure gauge. To rule out a dirty filter, check the pressure gauge number. If the pressure reading has risen any more than 8 points higher than it was when you last cleaned your pool filter, its time to clean the filter.
Look at the pool hose connections. If you see water leaking from any of the hose connections, it could be the cause of the vacuum leak. As water drips out, air gets in.
Listen to the Whisper Flo pump. Because the Whisper Flo pump was designed to operate with minimal noise, listen out for sounds such as a grinding or high-pitched whine. If you hear either sound, take it to a service technician for service. The sounds could mean the motor is in need of lubrication or the bearings need adjusting or replacement.