Can this be used to replace model 007-F5 and if so what speed should I use it on? Would it be better to use high speed for my second story zones?

Hello - yes, the Radiant Heating 3-Speed Circulator Pump (Lowe's item: 831074) can be used to replace model 007-F5. We would recommend using speed 1 or 2 for your intended applications. Should you have further questions or need further assistance please feel free to contact our Customer Support team at 1-877-700-4242 as we'd be more than happy to assist!