Boiler controller shows E04 and burner does not start; low water level alarm active.

Safety: Isolate power and allow boiler to cool. Never bypass low water level safety on a Danstoker boiler.

• Check system pressure and fill: Confirm that the system pressure is adequate on the pressure gauge. Open the make-up water valve and bleed air from radiators or system vents until pressure stabilizes.
• Inspect level probe: Locate the water level probe assembly on the boiler shell or level column. Isolate and remove the probe. Clean any scale or sludge from the electrode and sealing surfaces. Reinstall with new gasket if needed.
• Clean level chamber: If fitted with a level column or chamber, isolate and drain it. Remove inspection plugs and flush out sludge and scale. Ensure all isolation valves to the boiler are fully open after reassembly.
• Check wiring and level controller: Inspect the cable from the level probe to the Danstoker level control module. Tighten loose terminals. If the module shows level fault despite correct water level and clean probe, it may require replacement.

After cleaning and refilling, reset the controller and observe operation. If E04 returns, have a boiler specialist test the level safety system.