Nest thermostat E code e159

[fellosr]

I recently added the c wire, and I started getting the error e159. Before that my unit would work fine but occasionally would go offline for low battery. I decide to add the c wire to correct that however I get the e159 code which indicate no power to common (C). I took a voltmeter and it read 28 volt at the thermostat between the red and the common wire.

Please help or advise 

thank you 

[aatienza]

Hey fellosr,

Thanks for reaching out. Let's see what's going on — what's the make and model of your HVAC system? Do you have a heat pump? If so, the wire in the C terminal may be the changeover valve wire, or you may have a 2-wire changeover system. Also, try reinserting the C wire to see if that helps.

Thanks,

Archie

[aatienza]

Hey there,

I just wanted to follow up to see if you still need our help. Please let us know as we would be happy to answer any questions you may have. 
 

Thanks,

Archie

[aatienza]

Hello there,

Just checking in to make sure that you've seen our responses. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.
 

Thanks,

Archie