There is no voltage between C and R. In fact, from what I can trace, C
wire appears splitting from the R wire originated from the handler,
while the Y wire at the thermostat is going through the outside unit and
is connected to C terminal at the cont...
I had exactly the same issue. It seems a common problem. My C wire
(blue) doesn't have any voltage. Once disconnected from Nest thermostat,
cooling works, heating still works (my heating is gas).I've traced the
wire to the AC unit control board. The ...
I had the same or similar issue that when it turned off immediately
after it turned on, the display showed "No Power". As it turned out, my
C wire, even though it's present, doesn't appear to have voltage
(between R and C). Once I disconnected C wire...