Hello @Aero241 

- For best performance you could consider powerline kit of the same speed, or refer to the guide here to select more extenders. 

How can I select the powerline device?

In your case, to work with AV600, AV600/ AV1300 kit are more recommended. 

- Please check if the new powerline kit has been added into the old powerline network or not, download tpPLC Utility and check how many powerline units are found?  If only 2 units show up, that could due to new kit has not paired with the old kit yet,  please try to add more powerline unit as guide here:   How to add a device to the network using tpPLC Utility (new logo)?