Richard WeedonFeb 281 min readVaillant Fault Code F.23F.23 Safety switch-off: Temp.spread too large: Pump blocked, insufficient pump output, air in product, flow and return NTC connected the wrong way round Landlord gas safety inspection Cheshunt, Ware, Hertford0 views0 commentsPost not marked as liked
F.23 Safety switch-off: Temp.spread too large: Pump blocked, insufficient pump output, air in product, flow and return NTC connected the wrong way round Landlord gas safety inspection Cheshunt, Ware, Hertford