Defro Delayed Ignition

Boiler ignites with a loud bang or pop, especially after a long off period.

Safety Warning

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

Incorrect ignition electrode gap on Defro burner, Low gas pressure at ignition, Dirty burner head causing gas build-up, Slow-opening gas valve on Defro boiler

How to Fix / Troubleshooting

Safety: Delayed ignition can be dangerous. If bangs are loud or frequent, turn off the boiler and call a qualified gas technician.

Visual burner check: With power and gas off, inspect the Defro burner and ignition electrode for dirt and misalignment. Clean and adjust according to the service manual.
Gas supply: Ensure gas supply is stable and that other appliances are not affected.
Professional adjustment: A technician should check ignition gas rate, electrode position, and gas valve opening characteristics.

Repair Difficulty

Professional Required 5/5

Required Part

Defro ignition electrode set

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