How to reset a Vaillant ecoTEC boiler - AB Plumbing Heating
Vaillant F28 Fault Code Repair – MyBoiler.com
How to clear error F.28 & F.29 issue with Vaillant ecoTEC water heater - YouTube
Vaillant UK on Twitter: "If you are experiencing problems with your boiler related to fault codes F28 and F29, it may be likely your boiler condensate pipework has frozen. Here are some
Vaillant F28 Error Code - How To Fix (UK Guide) - iHeat
Vaillant Boilers' Problems: How to Fix Common Error Codes