Panasonic WH-SDF03E3E5 Series Design Handbook page 52

Products, functions and technical data
Accessories
Note
52
If two Aquareas are coupled together the secondary inlet and outlet
pipes must be balanced. The units must be fitted on the same level.
No valves must be fitted between the expansion vessel and the
storage cylinder(s).
Combination Valve
I.V. I.V.
Aquarea air / water heat pump – design handbook 07 / 2014