Technically the PBV4PS2 looks to be the same physical unit give or take - the PBV4NX Onyx edition is an exclusive WalMart retail version, so they had to hit their requirements and price point for them and the Pro Series PBV4PS2 is exclusively for Lowes at their price point. I'd call PB tech support, but me as an embedded systems electronics control systems engineer would give it a serious look. They all have an igniter and burner pot, internal temp probe, fan, and auger feed system. Working also for various OEMs over the years, you tend to keep parts SKUs low and HW and SW components common where possible to do this. The only thing that they may change to prevent parts swapping and "potential" premium feature upgrades is the connectors on the board and/or components. In any case it's worth looking into -- start by looking at the PBV4PS2 assembly instructions compared to yours (PBV4NX with regard to the wiring diagram. I looked at the 2 of them and they appear to have the same connections, the only thing that is not given is the physical board size.