On an Aria II, a worn motor/valve assembly will need a twist to get it started, since it will eventually start to jam when it closes. It will be intermittent at first, then become more and more frequent.
To replace it, get a new assembly and seals, close the water valve, disconnect the wiring harness from the controller, and remove the toilet. Remove the motor/valve assembly. The new assembly should come with new well nuts. Push the old ones into the toilet, put in the new ones, install the new assembly and seal, and reinstall the toilet.
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