How to clear error F.28 & F.29 issue with Vaillant ecoTEC water heater - YouTube
Vaillant Boiler F28 Error Code (causes & fixes)
Glow Worm Boiler Fault F.28 - It sounds like the boiler is trying to ignite, and having short bursts of ignition but not maintaining it. Any ideas? Can I fix it myself? :
Vaillant boiler error F 28 - YouTube
Vaillant F28 Fault Code Repair – MyBoiler.com
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Error f28 on Vaillant Boilers
Vaillant ecotec F28 fault code - Vaillant Boiler Repair Service
F. 28 error code Glowworm Betacom 3 - YouTube
VAILLANT ECOTEC BOILER F54, F28, F29 fault codes, what does this mean? And how to fix? Gas Valve? - YouTube