Water heater does not start at all; no display or lights.

Safety first: Before touching any wiring, switch off the main breaker. Only qualified persons should open electrical compartments.

• Check external supply: Verify that the wall socket or dedicated circuit has power using a known-good device or multimeter.
• Inspect fuses: Check the building fuse/breaker and any fuse inside the Protherm heater. Replace only with the same rating and type.
• Examine power cord and plug: Look for damage, burns, or loose connections. Replace damaged cords.
• Check internal terminals: Remove the front cover and verify that live, neutral, and earth are securely connected at the appliance terminal block.
• Test power switch: If fitted, test continuity of the on/off switch and replace if faulty.

Warning: If fuses blow repeatedly, do not keep replacing them; locate and repair the underlying fault.