Converting from a Trane XT500C AC Thermostat to Honeywell TB8220U1003 VisionPro 8000
Trane nomenclature's a bit different

Trane decided to be different (and a bit difficult) with their heat pump thermostat nomenclature: while O is indeed the reversing valve connection, they called the common B (blue) instead of C (for Common).  So, your correct wiring is:


White (W on the old 'stat) goes to W1 on the new 'stat
The jumper from W to X2 on the old 'stat gets discarded (X2 was emergency heat, but the Honeywell is smart enough to mux that onto W1 in heat pump mode)
Red (R on the old 'stat) goes to R on the new 'stat (the R-RC jumper stays put)
Tan (O on the old 'stat) goes to O/B on the new 'stat (some other people designate the reversing valve terminal as B, but Trane went and used that for the common terminal instead)
Yellow (Y1 on the old 'stat) goes to Y on the new 'stat
Green (G on the old 'stat) goes to G on the new 'stat
and Blue (B on the 'old stat) goes to C on the new 'stat (not to O/B where you have it now)