Boiler will not start at all; no display or lights

Safety: Electrical work should be done by a competent person. Isolate power before opening the boiler.

• 1. Check external power: Verify that the circuit breaker or fused spur supplying the Buderus boiler is on and that the fuse is intact.
• 2. Test outlet: If the boiler is plugged in, test the outlet with another appliance.
• 3. Inspect internal fuse: Remove the boiler front panel and locate the internal fuse(s) on the control board or power entry. Replace only with the same type and rating.
• 4. Terminal block: Check that the live, neutral, and earth wires are securely connected at the boiler terminal block.
• 5. Power supply board: If fuses and supply are good but the boiler remains dead, the power supply or main control board may be faulty and require replacement.