[C320-list] Seaward S600 Electric Water heater - how to reduce water temperature?

[Bob Borelli]

When the boat is in the slip and plugged into the 30 amp 120 volt receptacle, the S600 heats water up to its 'fixed Temperature Control thermostat set 140 degrees F.'  That is hot water coming out of the faucet plus it is adding heat into the already hot cabin.

Other than disconnecting the power wire from the the circuit breaker in the panel, any suggestions on reducing the water temperature or adding an ON/OFF switch in the 120V circuit?

When the diesel is operating, the fresh water in the S600 tank is heated by the engine coolant, not so hot and water seems to cool faster.
But a double whammy after powering into the slip and plugging in, its hot!

Thank you!
Bob Borelli
1995 C320 #209 SAI Sassafras River MD