BoilerFaultCodesWhat the manual says
Manufacturer manualThe product is within the waiting period of the modulation block/operating block function as a result of a water deficiency (flow/return spread too large).
From this model's manual
Verified against the Vaillant/Vaillant Ecotec Pro Ecotec Plus Combi installation & service manual.
DIY fix possible
Check your system pressure gauge to ensure it is sitting between 1 and 1.5 barUse the filling loop to top up the water pressure if it has dropped below 1 barCheck your radiators to see if any are cold and need bleeding to release trapped air
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Related fault codes
All 82 fault codes on the ecoTEC pro 30 H combi A VUW GB 306/5-3
Seeing a different code? Every code this model can display, in one place.
F.00F.01F.10F.11F.20F.22F.23F.24F.25F.26F.27F.28F.29F.32F.49F.61F.62F.63F.64F.65F.67F.68F.70F.71F.72F.73F.74F.75F.77F.78F.83F.84F.85S.00S.01S.02S.03S.04S.05S.06S.07S.08S.10S.11S.13S.14S.15S.16S.17S.20S.21S.22S.23S.24S.25S.26S.27S.28S.30S.31S.32S.34S.39S.40S.41S.42S.46S.54S.57S.58S.61S.62S.63S.76S.88S.92S.93S.96S.97S.98S.99