Quote Originally Posted by Poolsean
The Pure N CLear was designed to operate when the pump was on utilizing a noise sensor. This sensor was mounted on the pipe by the equipment. This was prone to false signals, such as lawnmowers.
This system did not really require the flow for it to operate.
The stuff that you may see coming back to the pool and looks like white flakes, which I can see may look like the inside of pipe deteriorating. It is calcium scale coming off the cell.
Noise sensor ? I think this one is magnetic:. sensor is glued on to the pump itself, seems to work very good: a few mVAC with pump off, 100m VAC @60Hz with pump on. Doesn't have any voltage applied to it, 1 side capacitively coupled to comparator circuit, other tied to local ground.

I did notice that the unit operates whether the pump is on or not, and was trying to troubleshoot that problem. I don't have the schematics, but I've traced out the relevent portion of the circuitry. Looks like a bad IC6 (LM2903), but even if I replace that, I don't see how the circuit will work - it looks like a basic desing error - needs a diode in signal path.

re pipes: yeah, that makes sense

MikeK