Відео

Yes, agreed! I have same question. It would work well when in heat in use mode, as flow would be forced through the heat exchanger and could not backflow at the heater exit as the closed valve blocks that. Conversely, there could be some flow through the heater when the valve is open (like pictured near end of video). At the t connection, some could reverse flow through the heater. I'd like to see them put a clear flow gauge on all legs of the system to prove out the paths.

​@tedk9144 yeah it is typical to not want water to flow through heater when not using it this would limit scale and other things. The raypak manual definitely states a check valve on the heater outlet. Since 3 way valve was not used to redirect I would at the least put a shut off valve on the heater inlet and still prefer a check valve on the outlet.