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Ask HVAC Guru Your Own Question
Category: HVAC
Satisfied Customers: 15048
Experience:  15yrs in the HVAC industry with certificates and degrees.
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Thanks for offering help, I just moved in the new house...

Customer Question

Hi... thanks for offering help
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: I just moved in the new house... replacing thermostat with Nest
JA: Just to clarify, do you think this is a larger HVAC problem, or something specific to the thermostat?
Customer: dealing with it one evening
JA: Do you plan on doing the work yourself?
Customer: getting error E23 (no power on red wire
JA: Anything else we should know to help you best?
Customer: I did it a number of times
Submitted: 1 year ago.
Category: HVAC
Expert:  HVAC Guru replied 1 year ago.

Hello and thanks for using this service, if you have been waiting do not worry or get upset. I am HVAC Guru an extremely experienced tech on the site and I try to get to as many customers as I can. I just picked up your question now. NOTE it takes time for me to type research and add links so please wait for me to respond back I can only do this so fast. Secondly I am not paid anything until you rate my service good using the STAR RATING LINK at the top of your page, the money is paid to the site not me directly.


You have to have a wire connected to the C terminal if you have that you should have 24 volts from the R wire to the C wire at the thermostat. If you do not have that you should check the wiring in the furnace or the fuse in the furnace on the control board as you have lost low voltage. If you replaced a battery thermostat with a NEST you would need to run a C wire to the unit or you will have to constantly recharge the nest with a micro USB cable like a Cell Phone.

All I ask is please use the Star Rating Link at the top of your page before leaving, that is the only way I am paid anything through the site and that will also get you a DIRECT LINK emailed to you to get back to me! are greatly appreciated so thank you very much for using this service. If you have any other questions just post back to me here anytime!