Vaillant Ecomax Pro 828E (Fault Codes) Leave a Comment / Boiler Fault Codes, Vaillant Boiler / By Emergency Plumbers / May 3, 2012 May 3, 2020 / Boiler Fault Codes, Domestic Gas Boiler, Vaillant, Vaillant Ecomax Pro 828E, Vaillant F Codes, Vaillant Fault Codes Vaillant Ecomax Pro 828E Fault Code Possible Cause F.00, .04, .05, .10, .14, .15 All of these are NTC faults, and are best resolved by first changing all NTC to make diagnosis earlier. F.21 The pilot flame has failed. F.22 There is insufficient water in your system. F.11 A blockage in the appliance is preventing the system from flowing as it should. F.12 A blockage in the appliance is affecting the system’s pressure. F.13 The appliance is blocked because of a water deficiency.