E195 Error but I have 27V at the red wire at both the furnace and the Nest base

[Vincevl]

Hi All,

We had a storm go thru today and I discovered my NEST is now displaying the error message E195.  No circuit breakers were tripped.  At the furnace I measure 27V between R and C and zero between W and C.

At the NEST base terminal block I measured 27V between R and C and zero between W and C.  We only run a furnace no A/C.

Any ideas of what could be the problem?  Many thanks for help.

[Markjosephp]

Hello Vincevl,

Thanks for reaching out to the Google Nest Community Forum. I'd be happy to take a look at this for you.

It's possible that your system won't supply the thermostat or a particular wire with any power at all, which would cause the thermostat to malfunction and display a report.

Could you please try removing the C wire and leaving it disconnected? Please turn off the power from your HVAC system at the breaker box before touching the wire. Also, gather the power readings in the Technical Info settings with and without the Common wire connected.

Let me know how it goes.

Best,
Mark

[Markjosephp]

Hey there,

Checking in to see if you still need help. In addition to the above step, check the air filter. A clog in the air filter can limit how much air flows over the cooling coils. If the clog persists, the system might shut off. Then, you can try uninstalling your Nest Thermostat and installing your old thermostat to better isolate it, so we can determine if it's a power and wiring issue. Lastly, inspect if the fuse gets damaged if it needs to be replaced, and ensure that you've turned off the power from your system before checking it.

Keep me posted.

Regards,
Mark

[Markjosephp]

Hi Vincevl,

I'm checking in to make sure that you've seen my response. Please let us know if you have any additional questions or concerns before we close this thread in 24 hours. 

Regards,

Mark