Pool pump loses prime

[coachsaca1226]

I have a solar pool heater in a home we just moved into. All the equipment works well except when I take out the pool cleaner before swimming. The pump has difficulty holding its prime and the pump basket loses some water. This only happens when the cleaner is not attached to the pool. Any ideas what would cause this? Thank you.

[Denniswiseman]

The short answer is air
How is thr cleaner connected, to the skimmer or vacuum port
Do you just lift it out or disconnect the hose from the pool first

[coachsaca1226]

It’s connected to a vacuum port. I generally turn off the pump. Then lift out the cleaner and turn the pump back on. The pump basket takes a while to fill back up. When I turn the pump off and back on again, the basket empties and then fills up again. Hope this makes sense.

[Denniswiseman]

Is the vacuum port still sucking when the hose is disconnected or is there a valve or other device to stop the suction

[coachsaca1226]

There is a flap on a spring hinge that covers the whole when the cleaner is out