Samsung EHS 904 fault code

What it means

DHW tank temperature sensor error

The dhw tank sensor sensor reads open or short circuit.

Safety: Safe isolation before disconnecting sensors or working on the PCB.

UK models this code applies to

From the Samsung service literature we hold (Samsung MWR-WW10N user & service manual DB68-08470A-17 (Appendix: error codes)) — not a scraped list.

Now the harder half: proving what caused it

904 names a symptom, not a root cause. In the app, the same code opens a guided investigation: what to measure first, the expected values for your exact model, and an honest verdict — including “nothing in this machine is broken” when that's what the readings say.