Two techs, one says the HRV duct cannot be tied into the return after a split. That the HRV duct must be before any splits in the return. The other tech has installed both ways.
On our install the return duct make a split very shortly before the AH plenum. This makes accomadating a HRV connection in that area nearly impossible. If the HRV duct can be after a split in the return system, there is lots of room in the attic to facilitate this and vent it out the side of a 30" closed soffit.