Flow Sensor: I have a slight preference for the mps 400 as it has an internal temperature sensor already integrated, does not have moving parts and is slightly smaller. Does this mps 400 specifically need access to the Aquabus High Flow socket because it is transmitting flow and temperature data together and that is why you should not connect the mps 400 to the "Flow" socket?
The internal temperature sensor for the MPS devices is used for the sensor calibration and is not in contact with the water, so it is not representative of the loop water temperature.
This sensor can not be connected to the flow connector of the aquabus because it communicates in a different way, over a bus, either USB or aquabus. The High flow model basically just gives impulses which the aquaero counts and calculates into flow.
MPS version is somewhat quieter, as the High flow version can produce a slight clicking noise, depending on the flow.
Kind regards,
Boris.