I installed two Nest thermostats onto separate zones of a two wire heating system and installed power connectors for each zone. One thermostat set up perfectly - no issues. The second thermostat refuses to detect the power connector and reports an N260 error. I've checked all the wire connections; they are identical for the two zones/connectors, so whatever was done works for one zone but not the other. Nevertheless both thermostats are seemingly controlling their respective zones despite the N260.
I've replaced the power connector for the mis-behaving thermostat, but the thermostat still reports an N260 error.
I've swapped the thermostats and the one from the good zone reports N260 when mounted on the bad zone while the thermostat from the bad zone does not report an error when mounted on the good zone.
The thermostat on the bad zone also drains the batteries faster than the one on the good zone, which is consistent with the undetected (or un-accessed) power connector and this is the real problem because I need to monitor this heading system remotely and am concerned that the batteries will die and the zone will be stuck in the off position during a cold snap.
Since neither thermostats nor the power connectors appear to be defective, I'm at a loss to figure out what the problem might be or how to fix it.
