Oso water heater shows E19 and may not follow programmed schedules.

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Failed backup battery on control PCB, Corrupted non‑volatile memory, Power interruptions during programming, Faulty control board

Safety first: Turn off power before removing the control cover.

Reprogram settings: Restore power and re‑enter time, date, and schedules. Observe if they are retained after a short power loss.
Check backup battery: Some Oso boards have a coin‑cell or supercap for memory backup. Replace if accessible and specified by the manufacturer.
Firmware reset: Perform a factory reset via the menu if available, then reconfigure.
Replace PCB: If E19 persists and settings are not retained, replace the main control PCB.

Medium 3/5

Oso main control PCB

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