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System boiler replaced recently, unable to clear air from radiators have bled them frequently, however they fill with air almost immediately. New boiler Ideal 15 fault codes appear FD and FU
3 header tanks on system two of them have open vents. Where is the air getting in and how can it be prevented. Only upstairs taxis get warm and only after bleeding
Grundfos 3speed pump set up high or boiler gives FU fault

I had hoped some one who knows the boiler would have answered, it is likely air drawn into the system due to pump speed being too high, I have seen this in the past, however you say you can't reduce pump speed, the first question has to be if only just fitted why are you not getting the installer back?

ericmark wrote:I had hoped some one who knows the boiler would have answered, it is likely air drawn into the system due to pump speed being too high, I have seen this in the past, however you say you can't reduce pump speed, the first question has to be if only just fitted why are you not getting the installer back?

Unfortunately due to the current situation and lockdown I cannot get him back in