Boiler Fault Codes

Modern boilers display fault codes when something goes wrong — but the same code can mean different things on a Worcester Bosch than it does on a Vaillant or Ideal. These guides break down the most common fault codes for every major UK boiler brand, explain what is actually happening inside the boiler, and tell you whether it is safe to reset and wait or whether you need to call a Gas Safe engineer. We cover Worcester Bosch Greenstar (4000, 8000, CDi, Si), Vaillant ecoTEC Plus, ecoTEC Pro, ecoFIT Pure, Ideal Logic, Logic+, Vogue Max, Baxi 600 and 800, Viessmann Vitodens 100-W and 200-W, Glow-worm Energy, Alpha E-Tec Plus, and Potterton.