The Vaillant Printed Circuit Board 0010028086 is a genuine Vaillant spare part with a Vaillant manufacturer's guarantee. A Printed Circuit Board (PCB) is a boiler's central electronic control. The PCB controls every function via the thermostats, switches, and sensors, ensuring the boiler runs safely and preventing it from working if any internal faults are detected. The PCB is essentially the brain of a boiler! This particular Printed Circuit Board replaces Vaillant Parts: 0020254533, 0020219272, 0020135165 & 0020108264. Part number: 0010028086. Fits: Vaillant EcoTEC Models 2012 Onwards. Always ensure a qualified engineer maintains your appliances on a regular basis.