Junkers Short Cycling / Unstable Combustion

Furnace starts but shuts down after a few seconds, no error code displayed

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 gas pressure, Blocked burner or injector, Faulty flame detection, Over-sensitive temperature sensor

Safety first: Turn off gas and power. Combustion issues can be hazardous.

1. Observe operation: Through the inspection window, note whether the flame is stable or lifts off and goes out.
2. Clean burner: Remove and clean the burner and injectors as per Junkers instructions.
3. Check sensors: Inspect and clean the ionisation electrode and temperature sensors. Replace if damaged.
4. Professional combustion check: Have a qualified technician measure gas pressures and adjust combustion using a flue gas analyser.

Professional Required 5/5

Burner Assembly

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