Another tech i work with is dealing with this. The FX07 has a BACnet/MSTP card in it, controls a heat pump, is exactly the same is 12 others in the building, and has worked for over a year.
Not it reads 0.0 so we replaced it with a new NRM and then another new NRM. Still reads 0.0F so we swap it with one from another heat pump and it reads normal.
The first 2 new NRMs were a slightly different model as you can set dip switches for address where the original just used the fixed 191 address. Program verified and reloaded even though the swap with the other heat pump proved that it was setup right.
So they ordered a brand new exact part number as original address 191 NRM and installed. Still reads 0.0
Any idea on this one? Seems strange to me and sounds like we are using the wrong part but they tell me it is the right one.