Hi!

I've spent a lot of time contemplating how these things are powered.
There are no wires running to the valve assembly. There is a small
encasement, but not large enough to hold a substantial battery supply,
which, IMHO, would be necessary to power some kind of solenoid valve.

Does anyone know how these things work? It would give me something
else to think about when I'm at work.

The one at my place of work is electric. It runs on 4xAA batteries that
supposedly last for at least 2,000 flush cycles. It is of the Sloan Valve
Company brand. That's as per the user's manual.

At first I thought that this thing might be recharged by water flow, but
sometimes the water pressure isn't very good...and as a result the unit
would not get charged up.

William