I didn't do our conversion myself, but the shop that did reused the existing wiring as needed. They were in the middle of a pretty large renovation project, so access to the outside of the tanks was pretty easy for them. I went with the 709 p3, which doesn't have the LP sensor. Not sure if that's wireless or not, but the battery/tanks reused the existing wires. Good luck, I've been very happy with the new system's operation and like the simplicity of the display. The new readout panel was ever so slightly smaller that the original MicroPulse, but not enough difference for me to want to modify the existing wall plate (meaning the new plate is mounted on top of the old part that's in the wall).