This decommissioned shower head heater is due to be thrown in the garbage. Before doing that to my former 11 year old heater, I wanted to open it up.
Step 1: Taking Off the Top.
Using a large flat blade screwdriver I removed the selector switch for warm off hot. You can see the power and ground wires easily.
Step 2: Accessing the Flow Switch.
These heaters contain a flow switch that relies on water pressure to force the movable contacts (3 of them) onto the fixed contacts below the top I removed. This top is held around the circumference by 5 Phillips head screws.
As you can clearly see, those contacts are pitted. I don't trust this arrangement for low pressure utility water supplies like in my area. Pitted contacts generate excess heat and will eventually cause failure of the heater. Since my old unit was in service for over a decade, I guess I got good life our of it regardless.
Step 3: Retrieving the Heater Element.
The base needs to be unscrewed to access the heater. This element is in good working condition so I shall keep it for use in the new shower head heater.