Vaillant 251955 fuse 2.0At

The Vaillant 251955 is a 2.0 A fuse used as a protective electrical component in Vaillant boiler and water heater assemblies. It sits in the appliance's electrical circuit and interrupts the supply when the current drawn exceeds its rated value, shielding the control board, wiring and other components from damage. It is a serviceable spare, typically reached for during fault-finding when an appliance has lost power altogether.

Because a fuse is a sacrificial part, it fails for a reason. Replacing it restores the circuit only if the underlying cause of the overcurrent has been identified and corrected.

• The appliance is completely dead, with no display, LEDs or audible response
• There is no reaction to a call for heat or hot water
• A multimeter shows no continuity across the fuse
• The fuse body is blackened, scorched or shows a broken element
• A replacement fuse blows again straight away, indicating a fault elsewhere in the circuit

• Confirm the rating on the removed fuse matches 2.0 A before fitting a replacement
• Check the part number 251955 against your appliance's parts list or the marking on the original component
• Isolate the electrical supply at the fused spur before removing or fitting the fuse
• If the fuse has failed more than once, trace the underlying electrical fault rather than continuing to replace the fuse