Water Heater No pressure

40 Gallon Gas Rheem water heater. We have low pressure on all the hot water taps in the house. While trouble shooting I pullled the cold water inlet off the top of the heater and discovered that at the top of the dip tube there is a plastic ball about 3/8" diameter with a stem sticking up about 3/4" stuck in the top of the dip tube. It is immobile, I can not move it at all. Is this supposed to be there? Whatever is it for?

I am trying to add a picture of it here:

Thanks in advance for any help I can get!

Bill

It's a heat trap. There's a corresponding one on the hot side. Water flow causes it to move, otherwise, it floats or drops to close when there is no flow.

So is mine just stuck? Should I try a little more force, to knock it free?

FIXED!! Tapped it gently with the end of a screw driver and a small hammer. It popped free and now I have hot water. Until it gets stuck again.