Read that Learning was better for Heat Pumps we've got a new one of those. We have an 12 year old Trane 4wcy4030 series that works like a champ with the old thermostat. Also works great jumping the wires (R,G,Y,O) blows cold (heat without the O). Hooking up the NL according to the 50 or so posts I've read here, the system turns on and shuts off after 7 seconds and continues this cycle until I through the breaker. Some of your posts say wire, filter, ... All done - new wire, new filter. Took the nest over to Dad's and it works great. Oddly, his comes up as a traditional electric HVAC because his wiring/programming has no OB wire on his Amana heat pump.
2 of your posts, experts say Trane units should send the blue to w2 - no luck there either, still cycles.
Other bits of info: No white wire, 5 wires total and blue is the other side of the transformer - giving "(C)ommon", have tried 'session' and 'season' on pro settings, reset in between all changes, Rh and Rc, and 'standard' wires/wiring/coloring according to Trane's installation guide, service manual, and schematic.
If I had to guess, the NL turns the system on and is not getting 'something' from the Trane within an expected period of time and shuts down (to protect ???) However, if the Nest is simply an on/off control, none of those 5 wires are returning any data (?).
Any thoughts, help, or other things to try would be greatly appreciated.
