For the KitchenAid KUID508ESS2, if by “water running all the time” you mean fresh water continually entering the reservoir, I’d start by separating a stuck inlet valve from a control/sensing problem.
Quickest test
While the water is continuously entering:
- Unplug the ice machine.
- Watch the incoming water.
If the water keeps flowing with the machine unplugged: the water inlet valve W10897719 is mechanically stuck open. Replace the valve. That valve is the model-listed inlet valve.
If the water stops immediately when unplugged: the valve itself is capable of closing. Something is keeping it electrically energized, so don’t replace the valve yet.
If it stops when unplugged
This model uses a water-level sensing system associated with the circulation pump. A bad water-level signal can cause incorrect reservoir filling; the model-listed circulation pump is W11542867.
I would check it in this order:
1. Watch the reservoir.
Does the reservoir fill and then water simply run down the overflow/drain continuously? If yes, the machine isn’t recognizing the proper water condition or isn’t shutting the fill command off.
2. Check the circulation pump/water-level sensing system.
Inspect the pump connector and wiring for corrosion, moisture, loose terminals, or damaged wires. The water-level sensing function is incorporated into this system on this version.
3. Check voltage at W10897719.
This is a live-voltage test, so use caution.
When the machine should not be filling, measure across the two inlet-valve terminals.
- ~120 VAC continuously: the control is commanding the valve open. Concentrate on the water-level sensing/pump circuit and ultimately the electronic control.
- 0 VAC but water continues: W10897719 is stuck mechanically open.
- Voltage appears only during the normal fill and then disappears: valve/control operation is normal; determine whether what you’re seeing is actually recirculation water rather than fresh supply water.
One important distinction: during normal ice production, this machine does continuously circulate water from the reservoir over the evaporator plate. That water running is normal. The fresh household water inlet should not run continuously.
If you tell me where you see the water running—into the reservoir, over the evaporator plate, or down the drain—I can narrow this down to the exact component/test.