Article reference KA-02560
Applicable to models: EDL170-520RF, EDL200UK-630RF, EDL270UK-630RF, EDL200UK-630, EDL270UK-630
If you want to connect the D2 pipe to a soil stack, you would also need a Hep-Vo valve for this, but in addition, you would also need to ensure the soil stack is suitably rated for the temperature of hot water that may vent to it in an emergency. See the technical bulletin from Wavin on this matter and if in doubt, consult local building control.
https://orbia.blob.core.windows.net/assets/F-33004-0.pdf
Condensate should be sent via trap as per M.I