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Gen 2 thermostat OFFLINE and Dead

Community Member

Yesterday the thermostat went offline and completely dead except for tiny green light flashing above the word nest at a rate that appears random. House cold. I performed the following tests:

  1. Checked router status and sure enough nest is the sole device missing from client list.
  2. Checked power and wiring at furnace and found 27 VAC between Common ( Blue wire) and the Rc (Red wire) only. All other wires especially W, call for heat  appeared open (~3 mV).
  3. Pulled non responsive nest and reproduced wiring voltage measurements at thermostat end, That is when I first noted flashing light.
  4. Replaced nest with iconic dumb Honeywell round thermostat. Bingo! Furnace fires up and heats house.
  5. Checked clock at 12:15 PM and went to bed.

So what now. Do I pronounce it and replace with another brand?