Baxi Fs 701s OF Boiler - continuously venting

[gdickin2]

Hi hope you can help. I have just changed the hot water cylinder connected to a Baxi Fs 701s OF boiler. For some reason the boiler now continuosly vents water back in to the boiler header tank which is also continuously filling up. It seems to have got stuck in some sort of loop where it is constantly recycling water through the boiler header tank.
I have not changed any of the pipework configuration to the cylinder as it was a straight one for one swap.
Any suggestions on what might be the problem ?

Many thanks

 

[JohnD]

if it has suddenly started doing it, then it is probably due to something you did.

either you have piped it wrong, or you have disturbed the sediment and caused an obstruction

please post a photo of the pipework round the cylinder and the pump, and say what you changed.

also, try turning the pump down to lowest speed