Boiler is completely dead; no display, no lights, and no response to controls

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

Steps to check:

• Check external power: Verify that the circuit breaker or fuse feeding the boiler has not tripped. Reset if necessary and observe if it trips again.
• Inspect power cable: Ensure the supply cable to the boiler is intact and not damaged.
• Check boiler main switch: Confirm that the boiler's own power switch is in the ON position and not faulty.
• Internal fuse: With power isolated, remove the boiler cover and locate the internal fuse on the control board or power module. Replace only with the same type and rating if blown.

When to call a technician: If fuses or breakers repeatedly trip, there is likely a short circuit or component failure that requires professional diagnosis.