Hi, yes I did look at the manual, but to be honest it wasnt clear to me what they were doing. I have a buffer tank, so the next question is how would I balance either side of the buffer? I have 2 manifolds and they both have the send to them and return all be it 10-15m apart. They are not casacaded ie ones return feeding the other which I believe can be the case.
My theory was the primary bypass wouldnt be needed as if the ASHP has a demand then there would be flow and if not then the pump would be off anyway and bypassing back a percentage of your hot water back to the tank will only lose heat on its trip round and this would be better just going round the manifold loops that was calling for heat.
I have to assume the installers didnt touch either primary or secondary.