Serious question, why does everyone say to factory reset a glitchy smart thermostat before checking the C-wire voltage?

After three callbacks for a Nest that kept dropping Wi-Fi, I finally just checked the voltage at the C terminal with my meter and found it was only 18V, not 24V, which a simple reset would never have fixed.

3 comments

3 Comments

spencer6643d ago

Starves the thing" is the whole tech support story now.

nathan_barnes16d ago

My third callback for a Honeywell was the same story. The homeowner had already done two resets, but the screen kept going blank. I put my meter on the C and R terminals and found 21 volts. That low voltage just starves the thing, and no amount of resetting will ever fix a power supply problem.

finley_flores2816d ago

My buddy's ecobee in Denver kept dying until we found 19 volts at the C wire.