When should ballast impellers be replaced?

[Andy1972]

So the brass center holding the impeller doesn’t come off? It slides off over the brass colored hub?

[charlesml3]

So the brass center holding the impeller doesn’t come off? It slides off over the brass colored hub?

Correct. Just grab the impeller vanes and tug. You may need to wiggle it from side to side but eventually it'll slide off the shaft.

-Charles